Some details of the 2AZ-FE engine

[Built_Well]

Gonna write this stuff down and post it so I don't lose it. Had
to wade through a lot of pages to find it. The 5th Generation Camry's
2AZ-FE engine (an advanced powerplant, by the way) is
the same engine that was used in the '01 Highlander SUV.
5th Generation Camrys cover Model Years '02 - '06.

The cylinder block is made of aluminum alloy. It uses aluminum
pistons, high-strength steel connecting rods and caps, forged steel
crankshaft, and, IIRC aluminum camshafts. The VVT-i only works
on the intake camshaft, not the exhaust camshaft. It varies
the timing of the intake valves. There are two intake valves per
cylinder and two exhaust valves per cylinder. Having two of
each increases the total port area, so more air can flow into
and out of the combustion chamber. As the manual's authors
write, "Intake and exhaust efficiency has been increased due
to the larger total port areas."

The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."

Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

The cylinder head gasket, used between the aluminum engine block
and the (iron?) cylinder head is a steel-laminate type of
material. Any concern about electrolysis taking place between
the steel-laminate and aluminum?

When the service and repair manual says the dry weight of the
engine is 267 pounds, does that include the crankcase, crank,
cylinder head, and valve head with camshafts--or does the
weight only include the engine block without crankcase
and cyclinder head, etc.?

The crankshaft and camshafts are connected by a timing chain,
not a belt.

The oil pump is located behind the timing chain cover at the
front bottom of the engine, even lower than the crankshaft. The oil
pump has
its own short section of chain that's connected to the
crankshaft. Couldn't tell from the picture if this is a second,
dedicated chain, or just part of the larger chain that ascends to
the camshafts. Double overhead cams, don't ya know (DOHC) :-)

If I had to guess, I'd say the oil pump has its own dedicated
short chain that's separate from the timing chain, ie., camshaft
chain..

[Ed White]

Post by Built_Well
Gonna write this stuff down and post it so I don't lose it. Had
to wade through a lot of pages to find it. The 5th Generation Camry's
2AZ-FE engine (an advanced powerplant, by the way)

Advanced, in what way? Lots of comparable engines from many manufacturers. I
have a hard time thinking of any engine that requires routine valve
adjustment as "advanced." But I guess that is also a trend these days. And
since most people ignore the routine valve clearance checks, I guess it is
irrelevant. I was shocked when I found out my Nissan Frontier requires valve
adjustment. You have to love the chutzpa of the Nissan engineers. The engine
in my Frontier requires valve adjustment only when the valve noise is
objectionable. It is going to be damn loud before I'll spend hundreds (maybe
thousands) to have the valves adjusted. I assume the engineers at Nissan
(and Toyota) have designed the valve system so that the valve clearance
increases with wear - else you run the risk of burning valves if the
clearance goes too low (learned from sad experience on older engines).

Post by Built_Well
is the same engine that was used in the '01 Highlander SUV.
5th Generation Camrys cover Model Years '02 - '06.

It is still used today in Camrys, RAV4s, and ?

Post by Built_Well
The cylinder block is made of aluminum alloy. It uses aluminum
pistons, high-strength steel connecting rods and caps, forged steel
crankshaft, and, IIRC aluminum camshafts. The VVT-i only works
on the intake camshaft, not the exhaust camshaft. It varies
the timing of the intake valves. There are two intake valves per
cylinder and two exhaust valves per cylinder. Having two of
each increases the total port area, so more air can flow into
and out of the combustion chamber. As the manual's authors
write, "Intake and exhaust efficiency has been increased due
to the larger total port areas."
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

Nope, it is aluminum.

Post by Built_Well
The cylinder head gasket, used between the aluminum engine block
and the (iron?) cylinder head is a steel-laminate type of
material. Any concern about electrolysis taking place between
the steel-laminate and aluminum?

Nope, but be sure to use the recommended coolant.

Post by Built_Well
When the service and repair manual says the dry weight of the
engine is 267 pounds, does that include the crankcase, crank,
cylinder head, and valve head with camshafts--or does the
weight only include the engine block without crankcase
and cyclinder head, etc.?

Everything that makes up the main engine assembly (block, pistons, heads,
cams, etc.) but no oil or water. Probably does not include accesorries
(alternator, starter). May or may not include intake system. Probably
includes intake to the throttle body.

Post by Built_Well
The crankshaft and camshafts are connected by a timing chain,
not a belt.

Common practice these days. Cam belts are mostly on the way out for modern
engines.

Post by Built_Well
The oil pump is located behind the timing chain cover at the
front bottom of the engine, even lower than the crankshaft. The oil
pump has its own short section of chain that's connected to the
crankshaft. Couldn't tell from the picture if this is a second,
dedicated chain, or just part of the larger chain that ascends to
the camshafts.

Completely separate chain (referred to as the No. 2 Chain Sub-assembly).

Post by Built_Well
Double overhead cams, don't ya know (DOHC) :-)
If I had to guess, I'd say the oil pump has its own dedicated
short chain that's separate from the timing chain, ie., camshaft
chain..

Correct.

Ed

[Built_Well]

Post by Ed White
Advanced, in what way? Lots of comparable engines from many manufacturers.

==========

Well, the manual, or something I read, said it was "advanced." I don't
think it was a case of self-promotion by the manual ;-)

You wrote, "I have a hard time thinking of any engine that
requires routine valve adjustment as advanced."

Well, it's not exactly routine. The scheduled maintenance
guide says to inspect the valve clearance after 120,000
miles or 12 years. 12 years is a long time.

When they say valve clearance, I guess they mean the
gap between the top of the valve stem and the bottom of
the lifter and/or tappet?

Anyone know if "lifter" and "tappet" are the same thing?

By the way, it's a shimless system.

Yes, the 2AZ-FE is still used today. I saw an '07 or
or '08 Solara with the 2AZ-FE, and the '08 Camry
owner's manual I bought off Ebay says the '08 Camry
also uses the 2AZ-FE. It's a very good engine. Toyota's
not gonna junk it anytime soon, I would guess.

By the way, that '08 Camry manual I got off Ebay says
the engine's drain-and-fill oil capacity with filter is
4.5 quarts. That's a whole 0.5 quarts more than my
'06 Camry manual says to use (4 quarts).

I thought maybe the new Camry might be using a bigger
filter, but without the filter the '08 Camry manual
says to use 4.3 quarts, again a half-quart more than
the 3.8 quarts called for in my '06 manual without filter.

Does anyone know why the two Toyota manuals recommend
different oil amounts for the same 2AZ-FE engine? That's
a big half-quart difference.

I have always put in 4.25 quarts, instead of the 4.0
quarts recommended in my manual, but do you think I should
increase it to 4.5 quarts, which would equal the
amount recommended in the new '08 manual?

Frothing probably wouldn't be a problem with that small
amount extra, but you never know.

[Built_Well]

Did I say frothing? I meant foaming--oil foaming.

The 2AZ-FE engine in both the '06 and '08 Camrys
is 2.4 liters.

[Ray O]

"Built_Well" <***@hotmail.com> wrote in message news:899682da-08dc-42cd-9f1b-***@x35g2000hsb.googlegroups.com...
<snipped>

Post by Built_Well
Does anyone know why the two Toyota manuals recommend
different oil amounts for the same 2AZ-FE engine? That's
a big half-quart difference.

The different oil capacities can be due to different capacities in the oil
pans, which are due to different shapes.

Post by Built_Well
I have always put in 4.25 quarts, instead of the 4.0
quarts recommended in my manual, but do you think I should
increase it to 4.5 quarts, which would equal the
amount recommended in the new '08 manual?

No. Stick to the recommended amount in your manual.

Post by Built_Well
Frothing probably wouldn't be a problem with that small
amount extra, but you never know.

It depends on how excided you get when you add the extra oil.

The oil is not going to foam with an extra half quart.

[Built_Well]

Post by Ray O
<snipped>

Post by Built_Well
Does anyone know why the two Toyota manuals recommend
different oil amounts for the same 2AZ-FE engine? That's
a big half-quart difference.

The different oil capacities can be due to different capacities in the oil
pans, which are due to different shapes.

Post by Built_Well
I have always put in 4.25 quarts, instead of the 4.0
quarts recommended in my manual, but do you think I should
increase it to 4.5 quarts, which would equal the
amount recommended in the new '08 manual?
=======================

No. Stick to the recommended amount in your manual.

Post by Built_Well
Frothing probably wouldn't be a problem with that small
amount extra, but you never know.

It depends on how excided you get when you add the extra oil.
The oil is not going to foam with an extra half quart.
--
Ray O
(correct punctuation to reply)

============================

Yeah, from what I've read online from reliable sources, an
extra 1/2 quart won't induce foaming, but a quart or more
is pushing it.

[Nate Nagel]

Post by Ed White

Post by Built_Well
Gonna write this stuff down and post it so I don't lose it. Had
to wade through a lot of pages to find it. The 5th Generation Camry's
2AZ-FE engine (an advanced powerplant, by the way)

Advanced, in what way? Lots of comparable engines from many manufacturers. I
have a hard time thinking of any engine that requires routine valve
adjustment as "advanced."

Solid lifters = less reciprocating mass, and higher RPM potential
because the lifters won't pump up. The reduction in reciprocating mass
allows the use of lighter valve springs for less friction. Doing away
with the need for oil feed to the lifters reduces the required capacity
of the oil pump and therefore pumping losses.

With careful design and material selection, the required valve
adjustment intervals can be quite long. I don't think I ever adjusted
the valves on my old Scirocco; by the time I'd collected the required
tools and shims I realized that the darn thing would just keep running
indefinitely whether I adjusted them or not. (for some inexplicable
reason, VW went to hydraulics anyway.) I did have the valve cover
gasket replaced once while it was in my care but I can't even remember
if I asked the mechanic to check the valve clearances or not. (don't
remember why I didn't do it myself.)

nate

[larry moe 'n curly]

Post by Ed White
I was shocked when I found out my Nissan Frontier requires valve
adjustment. You have to love the chutzpa of the Nissan engineers. The engine
in my Frontier requires valve adjustment only when the valve noise is
objectionable. It is going to be damn loud before I'll spend hundreds (maybe
thousands) to have the valves adjusted. I assume the engineers at Nissan
(and Toyota) have designed the valve system so that the valve clearance
increases with wear - else you run the risk of burning valves if the
clearance goes too low (learned from sad experience on older engines).

I have a 1998 with KA24DE engine. How can a valve adjustment with
this type of engine be so expensive? Are they charging that much for
the shim disks?

[C. E. White]

Post by larry moe 'n curly

Post by Ed White
I was shocked when I found out my Nissan Frontier requires valve
adjustment. You have to love the chutzpa of the Nissan engineers. The engine
in my Frontier requires valve adjustment only when the valve noise is
objectionable. It is going to be damn loud before I'll spend
hundreds (maybe
thousands) to have the valves adjusted. I assume the engineers at Nissan
(and Toyota) have designed the valve system so that the valve
clearance
increases with wear - else you run the risk of burning valves if the
clearance goes too low (learned from sad experience on older
engines).

I have a 1998 with KA24DE engine. How can a valve adjustment with
this type of engine be so expensive? Are they charging that much for
the shim disks?

I have the V6 in my Frontier. To replace the shims you have to remove
the cams - 4 of them. Hopefully I'll never need to have it done. I
guess things are much better now. Years ago I had a Jensen-Healey with
a DOHC 4 cylinder engine. Adjusting the valves was a nightmare - but
still easier than for the Frontier V-6.

Ed

[Steve]

Post by C. E. White

Post by larry moe 'n curly

Post by Ed White
I was shocked when I found out my Nissan Frontier requires valve
adjustment. You have to love the chutzpa of the Nissan engineers. The engine
in my Frontier requires valve adjustment only when the valve noise is
objectionable. It is going to be damn loud before I'll spend hundreds (maybe
thousands) to have the valves adjusted. I assume the engineers at Nissan
(and Toyota) have designed the valve system so that the valve clearance
increases with wear - else you run the risk of burning valves if the
clearance goes too low (learned from sad experience on older engines).

I have a 1998 with KA24DE engine. How can a valve adjustment with
this type of engine be so expensive? Are they charging that much for
the shim disks?

I have the V6 in my Frontier. To replace the shims you have to remove
the cams - 4 of them. Hopefully I'll never need to have it done. I guess
things are much better now. Years ago I had a Jensen-Healey with a DOHC
4 cylinder engine. Adjusting the valves was a nightmare - but still
easier than for the Frontier V-6.
Ed

Shims-in-a-bucket cam followers for valve adjustment is positively
stone-age (the last car I had so-equipped was a '78 Plymouth Horizon
with the VW-based SOHC 4). Rocker-tip mounted hydraulic lash adjusters
that are common now don't carry enough mass penalty to worry about and
are commonly used in engines with 7500+ RPM redlines. That said, I never
had to adjust the valves on that VW engine either. Everything else about
it sucked, but the valves never needed adjustment! ;P

[C. E. White]

Post by Steve
Shims-in-a-bucket cam followers for valve adjustment is positively
stone-age (the last car I had so-equipped was a '78 Plymouth Horizon with
the VW-based SOHC 4). Rocker-tip mounted hydraulic lash adjusters that are
common now don't carry enough mass penalty to worry about and are commonly
used in engines with 7500+ RPM redlines. That said, I never had to adjust
the valves on that VW engine either. Everything else about it sucked, but
the valves never needed adjustment! ;P

Numerous modern engines from Toyota and Nissan do not use hydraulic lash
adjustment. The most modern Camry V-6 does have hydraulic lash adjusters,
the older Camry V-6 and 4 cylinders do not. The engines without hydralic
lash adjustment do require routine valve clearance checking (if not actual
adjustment). I think this requirment is widely ignored. Interesting, Fords,
newest V-6 also does not have hydraulic valve adjustment - I guess they have
learned from Toyota.

Ed

[Steve]

Post by C. E. White

Post by Steve
Shims-in-a-bucket cam followers for valve adjustment is positively
stone-age (the last car I had so-equipped was a '78 Plymouth Horizon with
the VW-based SOHC 4). Rocker-tip mounted hydraulic lash adjusters that are
common now don't carry enough mass penalty to worry about and are commonly
used in engines with 7500+ RPM redlines. That said, I never had to adjust
the valves on that VW engine either. Everything else about it sucked, but
the valves never needed adjustment! ;P

Numerous modern engines from Toyota and Nissan do not use hydraulic lash
adjustment. The most modern Camry V-6 does have hydraulic lash adjusters,
the older Camry V-6 and 4 cylinders do not. The engines without hydralic
lash adjustment do require routine valve clearance checking (if not actual
adjustment). I think this requirment is widely ignored. Interesting, Fords,
newest V-6 also does not have hydraulic valve adjustment - I guess they have
learned from Toyota.

Probably a cost-of-production decision, IMO. rocker tip mounted
hydraulic lash adjusters are so tiny they don't add any appreciable mass
to the valvetrain, are almost impossible to "pump up" (I did a quick
calculation a while back that indicates it would require over 700 PSI of
oil pressure to "pump up" a lifter against valve spring pressure), and
keep the valve timing events right on spec over the life of the engine.

Don't forget, Toyota is learning from GM too. Learning how to live on
the laurels of the past and cut corners in the present. And how to
introduce a gas-guzzling pig of a truck just in the nick of time for
$4/gallon gas, leading to idling a shift at the new plant that builds it
in about 1 year of operation. That's gotta hurt. And that doesn't even
count the front suspension and brake recalls.... :-(

[Dyno]

Post by Steve

Post by C. E. White

Post by Steve
Shims-in-a-bucket cam followers for valve adjustment is positively
stone-age (the last car I had so-equipped was a '78 Plymouth Horizon
with the VW-based SOHC 4). Rocker-tip mounted hydraulic lash
adjusters that are common now don't carry enough mass penalty to
worry about and are commonly used in engines with 7500+ RPM redlines.
That said, I never had to adjust the valves on that VW engine either.
Everything else about it sucked, but the valves never needed
adjustment! ;P

Numerous modern engines from Toyota and Nissan do not use hydraulic
lash adjustment. The most modern Camry V-6 does have hydraulic lash
adjusters, the older Camry V-6 and 4 cylinders do not. The engines
without hydralic lash adjustment do require routine valve clearance
checking (if not actual adjustment). I think this requirment is widely
ignored. Interesting, Fords, newest V-6 also does not have hydraulic
valve adjustment - I guess they have learned from Toyota.

Probably a cost-of-production decision, IMO. rocker tip mounted
hydraulic lash adjusters are so tiny they don't add any appreciable mass
to the valvetrain, are almost impossible to "pump up" (I did a quick
calculation a while back that indicates it would require over 700 PSI of
oil pressure to "pump up" a lifter against valve spring pressure), and
keep the valve timing events right on spec over the life of the engine.
Don't forget, Toyota is learning from GM too. Learning how to live on
the laurels of the past and cut corners in the present. And how to
introduce a gas-guzzling pig of a truck just in the nick of time for
$4/gallon gas, leading to idling a shift at the new plant that builds it
in about 1 year of operation. That's gotta hurt. And that doesn't even
count the front suspension and brake recalls.... :-(

Actually, the reason to go to mechanical lash is not for high speed
valvetrain control but rather to reduce engine friction. The hydraulic
lash adjusters exert a significant amount of force on the cam base
circle, increasing mechanical friction. This IS both measureable and
does contribute to fuel savings. If you examine the base circle of the
came you can even see the lobe is narrower and flairs out to a wider
surface (Ford Zetec).

With modern oils and their additive packages, the need for frequent lash
adjustment is very rare. Most will make it thought the mandatory 100k
emissions durability requirements with no adjustment.

[Steve]

Post by Dyno
Actually, the reason to go to mechanical lash is not for high speed
valvetrain control but rather to reduce engine friction. The hydraulic
lash adjusters exert a significant amount of force on the cam base
circle, increasing mechanical friction. This IS both measureable and
does contribute to fuel savings. If you examine the base circle of the
came you can even see the lobe is narrower and flairs out to a wider
surface (Ford Zetec).

That would be a lot more palatable explanation if not for two factors:

1) Lash adjusters (unlike hydraulic lifters) are generally located at
the valve-stem end of the follower. They're about the diameter of a
valve stem, not a lifter. Therefore, the plunger inside them is about
the diameter of a valve stem, not order-of 5/8 inch like a lifter.
Taking the oil pressure and multiplying it by the surface area of the
lash adjuster plunger produces a TINY number. When lift begins the
valves in the lash adjuster close and the entrained oil is
incompressible so they don't collapse, but the BASE CIRCLE pressure is
solely due to engine oil pressure multiplied by plunger area, and is
miniscule.

2) With roller followers cam followers, adding base circle pressure
doesn't increase friction much at all. That's one big reason they're
used- far far lower friction than flat lifters from base circle all the
way to full lift. And of course they can follow a lobe profile with a
much sharper ramp rate so that you can get long duration without
excessive overlap.

Post by Dyno
With modern oils and their additive packages, the need for frequent lash
adjustment is very rare. Most will make it thought the mandatory 100k
emissions durability requirements with no adjustment.

No argument there, but I still think eliminating auto lash adjusters is
more cost-driven than engineering-driven. And I don't even disagree that
its a good idea to go ahead and save that money IF the engine can run
200k miles without opening the overhead, as we've come to expect from
cars with hydro lifters or hydro lash adjusters.

[Dyno]

Post by Steve

Post by Dyno
Actually, the reason to go to mechanical lash is not for high speed
valvetrain control but rather to reduce engine friction. The hydraulic
lash adjusters exert a significant amount of force on the cam base
circle, increasing mechanical friction. This IS both measureable and
does contribute to fuel savings. If you examine the base circle of the
came you can even see the lobe is narrower and flairs out to a wider
surface (Ford Zetec).

1) Lash adjusters (unlike hydraulic lifters) are generally located at
the valve-stem end of the follower. They're about the diameter of a
valve stem, not a lifter. Therefore, the plunger inside them is about
the diameter of a valve stem, not order-of 5/8 inch like a lifter.
Taking the oil pressure and multiplying it by the surface area of the
lash adjuster plunger produces a TINY number. When lift begins the
valves in the lash adjuster close and the entrained oil is
incompressible so they don't collapse, but the BASE CIRCLE pressure is
solely due to engine oil pressure multiplied by plunger area, and is
miniscule.

Not all hydraulic lash adjusters are that small. Some are actually
nearly the diameter of the bucket itself minus the wall thickness.
Nevertheless, I have seen the friction measurements and the mechanical
lash systems DO have lower friction.

How minuscule are we talking about here?
Sample base circle load calc:
Oil Pr : 60 psi
Adjuster Dia: 0.30 in
# Valves: 16 (4 cylinder)
60 psi x pi*(.15^2)*16 = 68 lbs is small? Maybe it is, but it certainly
is more than ~0.

I don't think this is negligible. And detailed engine friction studies
have verified the reduced friction using mechanical lash systems.

Post by Steve
2) With roller followers cam followers, adding base circle pressure
doesn't increase friction much at all. That's one big reason they're
used- far far lower friction than flat lifters from base circle all the
way to full lift. And of course they can follow a lobe profile with a
much sharper ramp rate so that you can get long duration without
excessive overlap.

Agreed, roller followers are in a different category and do have low
friction. But, they are costly and tend to be relatively bulky. Because
the roller assembly has to be controlled by the valve spring, they tend
to weigh more and are not as stiff as a direct acting bucket. Valvetrain
stiffness is critical when you have aggressive acceleration rates in
the opening/closing ramps.

Post by Steve

Post by Dyno
With modern oils and their additive packages, the need for frequent
lash adjustment is very rare. Most will make it thought the mandatory
100k emissions durability requirements with no adjustment.

No argument there, but I still think eliminating auto lash adjusters is
more cost-driven than engineering-driven. And I don't even disagree that
its a good idea to go ahead and save that money IF the engine can run
200k miles without opening the overhead, as we've come to expect from
cars with hydro lifters or hydro lash adjusters.

No doubt cost is a driving factor. But, if one can get equivalent
durability at a lower cost with some fuel savings, why not do it?
I know the simple mechanical valvetrains do pass the manufacturers 300
hr durability tests.

[N8N]

Post by Dyno

Post by Steve

Post by Dyno
Actually, the reason to go to mechanical lash is not for high speed
valvetrain control but rather to reduce engine friction. The hydraulic
lash adjusters exert a significant amount of force on the cam base
circle, increasing mechanical friction. This IS both measureable and
does contribute to fuel savings. If you examine the base circle of the
came you can even see the lobe is narrower and flairs out to a wider
surface (Ford Zetec).

1) Lash adjusters (unlike hydraulic lifters) are generally located at
the valve-stem end of the follower. They're about the diameter of a
valve stem, not a lifter. Therefore, the plunger inside them is about
the diameter of a valve stem, not order-of 5/8 inch like a lifter.
Taking the oil pressure and multiplying it by the surface area of the
lash adjuster plunger produces a TINY number.  When lift begins the
valves in the lash adjuster close and the entrained oil is
incompressible so they don't collapse, but the BASE CIRCLE pressure is
solely due to engine oil pressure multiplied by plunger area, and is
miniscule.

Not all hydraulic lash adjusters are that small. Some are actually
nearly the diameter of the bucket itself minus the wall thickness.
Nevertheless, I have seen the friction measurements and the mechanical
lash systems DO have lower friction.
How minuscule are we talking about here?
Oil Pr : 60 psi
Adjuster Dia: 0.30 in
# Valves: 16 (4 cylinder)
60 psi x pi*(.15^2)*16 = 68 lbs is small? Maybe it is, but it certainly
is more than ~0.
I don't think this is negligible. And detailed engine friction studies
have verified the reduced friction using mechanical lash systems.

Don't forget that you also have more reciprocating mass therefore the
valve springs would need to be heavier for the same RPM capability.

nate

[Steve]

Post by Dyno
How minuscule are we talking about here?
Oil Pr : 60 psi
Adjuster Dia: 0.30 in
# Valves: 16 (4 cylinder)
60 psi x pi*(.15^2)*16 = 68 lbs is small? Maybe it is, but it certainly
is more than ~0.

The base circle pressure doesn't matter if itdoesn't introduce any added
friction, and with today's roller followers it just doesnt.

Post by Dyno
I don't think this is negligible. And detailed engine friction studies
have verified the reduced friction using mechanical lash systems.

Post by Steve
2) With roller followers cam followers, adding base circle pressure
doesn't increase friction much at all. That's one big reason they're
used- far far lower friction than flat lifters from base circle all
the way to full lift. And of course they can follow a lobe profile
with a much sharper ramp rate so that you can get long duration
without excessive overlap.

Agreed, roller followers are in a different category and do have low
friction. But, they are costly and tend to be relatively bulky.

Yet they are virtually universally used! There's no point having a
raging debate about slider followers, it would be like arguing the
advantages of going back to drum brakes.

[Dyno]

Post by Steve

Post by Dyno
How minuscule are we talking about here?
Oil Pr : 60 psi
Adjuster Dia: 0.30 in
# Valves: 16 (4 cylinder)
60 psi x pi*(.15^2)*16 = 68 lbs is small? Maybe it is, but it
certainly is more than ~0.

The base circle pressure doesn't matter if itdoesn't introduce any added
friction, and with today's roller followers it just doesnt.

Post by Dyno
I don't think this is negligible. And detailed engine friction studies
have verified the reduced friction using mechanical lash systems.

Post by Steve
2) With roller followers cam followers, adding base circle pressure
doesn't increase friction much at all. That's one big reason they're
used- far far lower friction than flat lifters from base circle all
the way to full lift. And of course they can follow a lobe profile
with a much sharper ramp rate so that you can get long duration
without excessive overlap.

Agreed, roller followers are in a different category and do have low
friction. But, they are costly and tend to be relatively bulky.

Yet they are virtually universally used! There's no point having a
raging debate about slider followers, it would be like arguing the
advantages of going back to drum brakes.

Roller valvetrains are universally used? Er, ah I don't think so. For
example: I-4's in Mazda 3/6, Ford Focus and Fusion I-4's use direct
acting mechanical bucket tappets. Ford's 3.0L DOHC is a DAMB. These are
pretty mainstream engines.

And anyway the original discussion was NOT about roller finger follower
or other roller valvetrains. It was about hydraulic vs mechanical. You
added the roller valvetrain tangent. And I already agreed with you that
a roller valvetrain will have the lowest friction.

[Steve]

Post by Dyno
Roller valvetrains are universally used? Er, ah I don't think so. For
example: I-4's in Mazda 3/6, Ford Focus and Fusion I-4's use direct
acting mechanical bucket tappets. Ford's 3.0L DOHC is a DAMB. These are
pretty mainstream engines.
And anyway the original discussion was NOT about roller finger follower
or other roller valvetrains. It was about hydraulic vs mechanical. You
added the roller valvetrain tangent. And I already agreed with you that
a roller valvetrain will have the lowest friction.

I said "virtually" universally used, and that's true because roller-cam
engines outnumber sliders at least 10:1 in the marketplace. One or two
low-end Ford/Mazda engines do not a majority make, even if millions are
sold. You can't debate the virtues of hydro lash adjusters without
putting it in the context of roller vs. slider, because roller followers
eliminate some of the presumed disadvantages of hydro lash adjusters.
That was the only point I intended, and I don't think I disagreed with
you either. IF you are constrained to a slider cam for cost reasons,
then it makes sense to eliminate the lash adjusters too. Its "system"
design thinking vs. "component" design thinking- what pieces work
TOGETHER the best.

[Retired VIP]

On Wed, 23 Jul 2008 16:26:59 -0400, "C. E. White"

Post by C. E. White

Post by Steve
Shims-in-a-bucket cam followers for valve adjustment is positively
stone-age (the last car I had so-equipped was a '78 Plymouth Horizon with
the VW-based SOHC 4). Rocker-tip mounted hydraulic lash adjusters that are
common now don't carry enough mass penalty to worry about and are commonly
used in engines with 7500+ RPM redlines. That said, I never had to adjust
the valves on that VW engine either. Everything else about it sucked, but
the valves never needed adjustment! ;P

Numerous modern engines from Toyota and Nissan do not use hydraulic lash
adjustment. The most modern Camry V-6 does have hydraulic lash adjusters,
the older Camry V-6 and 4 cylinders do not. The engines without hydralic
lash adjustment do require routine valve clearance checking (if not actual
adjustment). I think this requirment is widely ignored. Interesting, Fords,
newest V-6 also does not have hydraulic valve adjustment - I guess they have
learned from Toyota.
Ed

I guess I'm just to stupid for my shirt. How is increasing the amount
of necessary routine maintenance as well as increasing the cost of
operation a step forward?

Jack

[Leftie]

Post by Retired VIP
On Wed, 23 Jul 2008 16:26:59 -0400, "C. E. White"

Post by C. E. White

Post by Steve
Shims-in-a-bucket cam followers for valve adjustment is positively
stone-age (the last car I had so-equipped was a '78 Plymouth Horizon with
the VW-based SOHC 4). Rocker-tip mounted hydraulic lash adjusters that are
common now don't carry enough mass penalty to worry about and are commonly
used in engines with 7500+ RPM redlines. That said, I never had to adjust
the valves on that VW engine either. Everything else about it sucked, but
the valves never needed adjustment! ;P

Numerous modern engines from Toyota and Nissan do not use hydraulic lash
adjustment. The most modern Camry V-6 does have hydraulic lash adjusters,
the older Camry V-6 and 4 cylinders do not. The engines without hydralic
lash adjustment do require routine valve clearance checking (if not actual
adjustment). I think this requirment is widely ignored. Interesting, Fords,
newest V-6 also does not have hydraulic valve adjustment - I guess they have
learned from Toyota.
Ed

I guess I'm just to stupid for my shirt. How is increasing the amount
of necessary routine maintenance as well as increasing the cost of
operation a step forward?
Jack

There are two problems with hydraulic lifters: they are more
expensive to build and, more to the point for us, they tend to fail long
before the rest of the engine. Who wants to have to spend $1k on new
lifters on a car with 150k miles on it? The shim & bucket type setup
rarely needs adjustment when properly designed (and it is as used by
Toyota and Volvo in their older engines) and it doesn't fail. I've had
two cars and one motorcycle suffer from hydraulic lifter failure. I'd
much rather have the valves adjusted every 5 years or so.

[Scott Dorsey]

Post by Leftie
There are two problems with hydraulic lifters: they are more
expensive to build and, more to the point for us, they tend to fail long
before the rest of the engine. Who wants to have to spend $1k on new
lifters on a car with 150k miles on it? The shim & bucket type setup
rarely needs adjustment when properly designed (and it is as used by
Toyota and Volvo in their older engines) and it doesn't fail. I've had
two cars and one motorcycle suffer from hydraulic lifter failure. I'd
much rather have the valves adjusted every 5 years or so.

The unfortunate problem is that most people don't do proper maintenance on
their vehicles. As a consequence, manufacturers design cars to avoid
the need for that maintenance because, given the poor treatment of the
average owner, the car will last longer as a result.

This means hydraulic lifters, but it also means sealed chassis components
that don't need regular greasing with every oil change but which fail
before 80,000 miles is up. It means "sealed for life" transmissions, where
that life is about half what it should be.

This is what the market demands, and it's what is best for the average car
owner today. Sadly it's not what is best for folks who actually intend on
taking good care of their vehicles, but those people are in a small minority
and probably always have been.
--scott

[Steve]

Post by Scott Dorsey
This means hydraulic lifters, but it also means sealed chassis components
that don't need regular greasing with every oil change but which fail
before 80,000 miles is up. It means "sealed for life" transmissions, where
that life is about half what it should be.

Here here! Eliminating the dipstick on automatic transmissions has to
be the single most unnecessarily STUPID thing car makers have done in
the last 50 years. Maybe since the dawn of the automobile.

[C. E. White]

Post by Steve

Post by Scott Dorsey
This means hydraulic lifters, but it also means sealed chassis components
that don't need regular greasing with every oil change but which fail
before 80,000 miles is up. It means "sealed for life"
transmissions, where
that life is about half what it should be.

Here here! Eliminating the dipstick on automatic transmissions has
to be the single most unnecessarily STUPID thing car makers have
done in the last 50 years. Maybe since the dawn of the automobile.

Why? All my current cars still have dip sticks on the transmission,
but there never seems to be any change in the level. I think
eliminating dipsticks was a safety measure more than anything else - I
remember reading that a significant number of transmissions were
damaged because either they were over filled (people don't follow the
instructions for using them) or the wrong lubricant was added tot he
transmission through the dip stick hole (wrong ATF or just the wrong
stuff - like engine oil). How may car owners ever use the automatic
transmission dip stick?

Ed

[Steve]

How may car owners ever use the automatic transmission dip stick?

All of them with half a brain.


How often do you actually add ENGINE oil? I never need to between
changes, but I still CHECK it weekly. Same with the transmission fluid.
The whole idea of maintenance is to CATCH a potential problem before it
becomes costly. Eliminating the transmission dipstick pretty much
guarantees a low-fluid failure will ultimately destroy the transmission,
be it at 10,000 miles or 200,000 miles.

[Vic Smith]

Post by Steve

How may car owners ever use the automatic transmission dip stick?

All of them with half a brain.
How often do you actually add ENGINE oil? I never need to between
changes, but I still CHECK it weekly. Same with the transmission fluid.
The whole idea of maintenance is to CATCH a potential problem before it
becomes costly. Eliminating the transmission dipstick pretty much
guarantees a low-fluid failure will ultimately destroy the transmission,
be it at 10,000 miles or 200,000 miles.

Hard to imagine not having a trans dipstick.
Might as well tell this story, even if it's about my U of I engineer
son.
He had a Hyudai something or other. Saw it a couple times and it
looked and sounded decent enough.
He drove it almost every weekend from Champagne to Chicago and back.
He bought it used, and had a couple grand in it.
One Friday he calls me from his mom's house saying his check oil light
is coming on, but the dipstick shows normal.
He said he had an oil change a few weeks ago at a fast change place,
checked the oil after that and has been checking it at least every
week.
I told him he might have bad mains, bad oil pump, or a bad sender, and
to get it to my mechanic to have it checked out.
But it was the weekend and he had to get back to school.
Sunday evening a daughter is visiting me, driving the son's Hyundai
because her car is down. I walked her out to the Hyandai when she had
to get back so the son could take off for school.
I chatted with her a bit before she pulled out, and the Hyandai didn't
sound bad. Didn't see or smell oil burning. No drips on the
driveway. Something told me to check the oil, just out of habit, but
she was in a hurry and I pushed it aside.
Next morning she calls to say the car broke down on him on the way to
school. Engine shot. The tow truck driver found it dry of oil.
Turns out my son had been checking the trans dipstick the whole time.
Saw his mistake when the tow driver pulled the right dipstick.
Can't tell you how bad I felt in not checking the oil when it was in
my driveway, but I really never thought for a second my "smart" kid
couldn't check his own oil. He's a successful engineer now, but still
doesn't give a crap about cars. He does know how to pick the right
dipstick though.

--Vic

[Steve]

Post by Vic Smith

Post by Steve

How may car owners ever use the automatic transmission dip stick?

All of them with half a brain.
How often do you actually add ENGINE oil? I never need to between
changes, but I still CHECK it weekly. Same with the transmission fluid.
The whole idea of maintenance is to CATCH a potential problem before it
becomes costly. Eliminating the transmission dipstick pretty much
guarantees a low-fluid failure will ultimately destroy the transmission,
be it at 10,000 miles or 200,000 miles.

Hard to imagine not having a trans dipstick.

Open the hood of any late model Toyota. :-(

[Retired VIP]

Post by Steve

Post by Vic Smith

Post by Steve

How may car owners ever use the automatic transmission dip stick?

All of them with half a brain.
How often do you actually add ENGINE oil? I never need to between
changes, but I still CHECK it weekly. Same with the transmission fluid.
The whole idea of maintenance is to CATCH a potential problem before it
becomes costly. Eliminating the transmission dipstick pretty much
guarantees a low-fluid failure will ultimately destroy the transmission,
be it at 10,000 miles or 200,000 miles.

Hard to imagine not having a trans dipstick.

Open the hood of any late model Toyota. :-(

2006 Corolla has them. I think that's a late model Toyota.

Jack

[Steve]

Post by Leftie
There are two problems with hydraulic lifters: they are more
expensive to build and, more to the point for us, they tend to fail long
before the rest of the engine. Who wants to have to spend $1k on new
lifters on a car with 150k miles on it?

They FAIL before the rest of the engine? Hardly. Ask any mechanic how
many hydraulic lifters or lash adjusters he's had to replace because the
lifter or adjuster ITSELF was a root cause of a problem in the last 10
years and I'll bet you can count the average answer on 1 hand, and if
you probe further you'll find that those were typically in badly
neglected sludged-up engines.

[Leftie]

Post by Steve

Post by Leftie
There are two problems with hydraulic lifters: they are more
expensive to build and, more to the point for us, they tend to fail long
before the rest of the engine. Who wants to have to spend $1k on new
lifters on a car with 150k miles on it?

They FAIL before the rest of the engine? Hardly. Ask any mechanic how
many hydraulic lifters or lash adjusters he's had to replace because the
lifter or adjuster ITSELF was a root cause of a problem in the last 10
years and I'll bet you can count the average answer on 1 hand, and if
you probe further you'll find that those were typically in badly
neglected sludged-up engines.

My engines were not "badly neglected". The motorcycle was given full
synthetic oil. The two Mazda engines may have had poorly designed oil
passages, but I've also heard from other people abut lifters failing.
Think of all the "stuck lifter" stories out there, and you may realize
that it isn't just bad maintainance causing it to happen.

[Retired VIP]

Post by Leftie

Post by Retired VIP
On Wed, 23 Jul 2008 16:26:59 -0400, "C. E. White"

Post by C. E. White

Post by Steve
Shims-in-a-bucket cam followers for valve adjustment is positively
stone-age (the last car I had so-equipped was a '78 Plymouth Horizon with
the VW-based SOHC 4). Rocker-tip mounted hydraulic lash adjusters that are
common now don't carry enough mass penalty to worry about and are commonly
used in engines with 7500+ RPM redlines. That said, I never had to adjust
the valves on that VW engine either. Everything else about it sucked, but
the valves never needed adjustment! ;P

Numerous modern engines from Toyota and Nissan do not use hydraulic lash
adjustment. The most modern Camry V-6 does have hydraulic lash adjusters,
the older Camry V-6 and 4 cylinders do not. The engines without hydralic
lash adjustment do require routine valve clearance checking (if not actual
adjustment). I think this requirment is widely ignored. Interesting, Fords,
newest V-6 also does not have hydraulic valve adjustment - I guess they have
learned from Toyota.
Ed

I guess I'm just to stupid for my shirt. How is increasing the amount
of necessary routine maintenance as well as increasing the cost of
operation a step forward?
Jack

There are two problems with hydraulic lifters: they are more
expensive to build and, more to the point for us, they tend to fail long
before the rest of the engine. Who wants to have to spend $1k on new
lifters on a car with 150k miles on it? The shim & bucket type setup
rarely needs adjustment when properly designed (and it is as used by
Toyota and Volvo in their older engines) and it doesn't fail. I've had
two cars and one motorcycle suffer from hydraulic lifter failure. I'd
much rather have the valves adjusted every 5 years or so.

Ok, I'll grant that hydraulic lifters are more expensive to build but
'they tend to fail long before the rest of the engine'? Maybe for
people who don't change their oil but in over 35 years of car
ownership, I've NEVER had hydraulic lifters fail. I have heard a lot
of cars with solid lifters clicking and clacking down the road
sounding like an old Singer sewing machine and punching holes in their
rocker arms.

This would seem to me to be another example of why bean-counters
should be kept in a locked room. They should never be allowed to
attend management meetings or review mechanical drawings.

Jack

[EdV]

Post by Ed White

Post by Built_Well
Gonna write this stuff down and post it so I don't lose it. Had
to wade through a lot of pages to find it. The 5th Generation Camry's
2AZ-FE engine (an advanced powerplant, by the way)

Advanced, in what way? Lots of comparable engines from many manufacturers. I
have a hard time thinking of any engine that requires routine valve
adjustment as "advanced." But I guess that is also a trend these days. And
since most people ignore the routine valve clearance checks, I guess it is
irrelevant. I was shocked when I found out my Nissan Frontier requires valve
adjustment. You have to love the chutzpa of the Nissan engineers. The engine
in my Frontier requires valve adjustment only when the valve noise is
objectionable. It is going to be damn loud before I'll spend hundreds (maybe
thousands) to have the valves adjusted. I assume the engineers at Nissan
(and Toyota) have designed the valve system so that the valve clearance
increases with wear - else you run the risk of burning valves if the
clearance goes too low (learned from sad experience on older engines).

Post by Built_Well
is the same engine that was used in the '01 Highlander SUV.
5th Generation Camrys cover Model Years '02 - '06.

It is still used today in Camrys, RAV4s, and ?

Post by Built_Well
The cylinder block is made of aluminum alloy. It uses aluminum
pistons, high-strength steel connecting rods and caps, forged steel
crankshaft, and, IIRC aluminum camshafts. The VVT-i only works
on the intake camshaft, not the exhaust camshaft. It varies
the timing of the intake valves. There are two intake valves per
cylinder and two exhaust valves per cylinder. Having two of
each increases the total port area, so more air can flow into
and out of the combustion chamber. As the manual's authors
write, "Intake and exhaust efficiency has been increased due
to the larger total port areas."
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

Nope, it is aluminum.

Post by Built_Well
The cylinder head gasket, used between the aluminum engine block
and the (iron?) cylinder head is a steel-laminate type of
material. Any concern about electrolysis taking place between
the steel-laminate and aluminum?

Nope, but be sure to use the recommended coolant.

Post by Built_Well
When the service and repair manual says the dry weight of the
engine is 267 pounds, does that include the crankcase, crank,
cylinder head, and valve head with camshafts--or does the
weight only include the engine block without crankcase
and cyclinder head, etc.?

Everything that makes up the main engine assembly (block, pistons, heads,
cams, etc.) but no oil or water. Probably does not include accesorries
(alternator, starter). May or may not include intake system. Probably
includes intake to the throttle body.

Post by Built_Well
The crankshaft and camshafts are connected by a timing chain,
not a belt.

Common practice these days. Cam belts are mostly on the way out for modern
engines.

Post by Built_Well
The oil pump is located behind the timing chain cover at the
front bottom of the engine, even lower than the crankshaft. The oil
pump has its own short section of chain that's connected to the
crankshaft. Couldn't tell from the picture if this is a second,
dedicated chain, or just part of the larger chain that ascends to
the camshafts.

Completely separate chain (referred to as the No. 2 Chain Sub-assembly).

Post by Built_Well
Double overhead cams, don't ya know (DOHC) :-)
If I had to guess, I'd say the oil pump has its own dedicated
short chain that's separate from the timing chain, ie., camshaft
chain..

Correct.
Ed

Is the 2AZ-FE considered a direct injection engine?

[C. E. White]

Post by EdV
Is the 2AZ-FE considered a direct injection engine?

No.

Ed

[Built_Well]

Is the 2AZ-FE considered a direct injectin engine?

No

=============

The 2AZ-FE is a direct injection engine. It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

[Nate Nagel]

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine. It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.

What you are describing is a "distributorless ignition."

nate

[Built_Well]

Post by Nate Nagel

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine. It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.
What you are describing is a "distributorless ignition."
nate

============================================

Very good information. I enjoyed reading it, and you're
right that the Camry does not inject fuel into the combustion
chamber but into the "antechamber" in the cylinder head that
comes just before the valve. That's what the manual's diagram
seems to show anyway.

But the 2AZ-FE /is/ a Direct Injection System. Here's a quote
from the Camry's service and repair manual on Page EG-57:

"A DIS (Direct Ignition System) has been adopted. The DIS improves
the ignition timing accuracy, reduces high-voltage loss, and
enhances the overall reliability of the ignition system by
eliminating the distributor. The DIS in this engine is an
independent ignition system which has one ignition coil (with
igniter) for each cylinder."

Also, the book "Auto Upkeep" says, "Some manufacturers call the
distributor-less ignition system a direct ignition system."

Maybe there are two sides with an honest difference of opinion?
Sorta like how API Group III oils are considered synthetic in
the U.S.A., but not in Europe.

However, the book says there are 3 types of ignition systems:

Conventional, Electronic, and Distributor-less.

The web site ProCarCare.com doesn't mention firing into the
combustion chamber as a pre-requisite for D.I.S.

Here's a quote:

The Direct Ignition System (DIS) uses either a magnetic crankshaft
sensor, camshaft position sensor, or both, to determine crankshaft
position and engine speed. This signal is sent to the ignition
control module or engine control module which then energizes the
appropriate coil.

You obviously know a whole lot more about cars than I do, but the
2AZ-FE does seem to be a Direct Ignition System.

Here's a link to the ProCarCare site with the info:

http://www.procarcare.com/icarumba/resourcecenter/encyclopedia/icar_resourcecenter_encyclopedia_ignition.asp

Britannica Online seems to agree:

direct-ignition system, or distributor-less ignition system
(engineering):

description and use:

Many automobile engines now use a distributor-less ignition
system, or direct-ignition system, in which a high-voltage pulse
is directly applied to coils that sit on top of the spark plugs
(known as coil-on-plug). The major components of these systems
are a coil pack, an ignition module, a crankshaft reluctor ring,
a magnetic sensor, and an electronic control module.

From Wikipedia's entry on Ignition System:

Other systems dispense with the distributor and coil and use
special spark plugs which each contain their own coil
(Direct Ignition). This means high voltages are not routed all
over the engine, but are instead created at the point at which
they are needed. Such designs offer potentially much greater
reliability than conventional arrangements.

A site devoted to the Honda Insight says this:

The Insight engine employs a direct ignition system similar to
those used on the Honda S2000 and the 1999 Odyssey. Separate
ignition coils for each cylinder are located directly above
the spark plugs.

[N8N]

Post by Built_Well

Post by Nate Nagel

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine.  It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.
What you are describing is a "distributorless ignition."
nate

============================================
Very good information.  I enjoyed reading it, and you're
right that the Camry does not inject fuel into the combustion
chamber but into the "antechamber" in the cylinder head that
comes just before the valve.  That's what the manual's diagram
seems to show anyway.
But the 2AZ-FE /is/ a Direct Injection System.  Here's a quote
"A DIS (Direct Ignition System) has been adopted. The DIS improves
the ignition timing accuracy, reduces high-voltage loss, and
enhances the overall reliability of the ignition system by
eliminating the distributor.  The DIS in this engine is an
independent ignition system which has one ignition coil (with
igniter) for each cylinder."
Also, the book "Auto Upkeep" says, "Some manufacturers call the
distributor-less ignition system a direct ignition system."
Maybe there are two sides with an honest difference of opinion?
Sorta like how API Group III oils are considered synthetic in
the U.S.A., but not in Europe.
Conventional, Electronic, and Distributor-less.
The web site ProCarCare.com doesn't mention firing into the
combustion chamber as a pre-requisite for D.I.S.
The Direct Ignition System (DIS) uses either a magnetic crankshaft
sensor, camshaft position sensor, or both, to determine crankshaft
position and engine speed.  This signal is sent to the ignition
control module or engine control module which then energizes the
appropriate coil.
You obviously know a whole lot more about cars than I do, but the
2AZ-FE does seem to be a Direct Ignition System.
http://www.procarcare.com/icarumba/resourcecenter/encyclopedia/icar_r...
direct-ignition system, or distributor-less ignition system
  Many automobile engines now use a distributor-less ignition
system, or direct-ignition system, in which a high-voltage pulse
is directly applied to coils that sit on top of the spark plugs
(known as coil-on-plug). The major components of these systems
are a coil pack, an ignition module, a crankshaft reluctor ring,
a magnetic sensor, and an electronic control module.
Other systems dispense with the distributor and coil and use
special spark plugs which each contain their own coil
(Direct Ignition). This means high voltages are not routed all
over the engine, but are instead created at the point at which
they are needed. Such designs offer potentially much greater
reliability than conventional arrangements.
The Insight engine employs a direct ignition system similar to
those used on the Honda S2000 and the 1999 Odyssey. Separate
ignition coils for each cylinder are located directly above
the spark plugs.- Hide quoted text -
- Show quoted text -

Your original post said "direct INJECTION" not "direct IGNITION."
I've never heard of a distributorless ignition called a "direct
ignition" although I guess it kind of makes sense for a coil-on-plug
type setup. Now direct INJECTION refers to something completely
different, as I described in my post. Generally used on Diesel
engines although I have heard that some mfgrs. have or will introduce
it on gas engines as well.

nate

[N8N]

Post by N8N

Post by Built_Well

Post by Nate Nagel

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine.  It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.
What you are describing is a "distributorless ignition."
nate

============================================
Very good information.  I enjoyed reading it, and you're
right that the Camry does not inject fuel into the combustion
chamber but into the "antechamber" in the cylinder head that
comes just before the valve.  That's what the manual's diagram
seems to show anyway.
But the 2AZ-FE /is/ a Direct Injection System.  Here's a quote
"A DIS (Direct Ignition System) has been adopted. The DIS improves
the ignition timing accuracy, reduces high-voltage loss, and
enhances the overall reliability of the ignition system by
eliminating the distributor.  The DIS in this engine is an
independent ignition system which has one ignition coil (with
igniter) for each cylinder."
Also, the book "Auto Upkeep" says, "Some manufacturers call the
distributor-less ignition system a direct ignition system."
Maybe there are two sides with an honest difference of opinion?
Sorta like how API Group III oils are considered synthetic in
the U.S.A., but not in Europe.
Conventional, Electronic, and Distributor-less.
The web site ProCarCare.com doesn't mention firing into the
combustion chamber as a pre-requisite for D.I.S.
The Direct Ignition System (DIS) uses either a magnetic crankshaft
sensor, camshaft position sensor, or both, to determine crankshaft
position and engine speed.  This signal is sent to the ignition
control module or engine control module which then energizes the
appropriate coil.
You obviously know a whole lot more about cars than I do, but the
2AZ-FE does seem to be a Direct Ignition System.
http://www.procarcare.com/icarumba/resourcecenter/encyclopedia/icar_r...
direct-ignition system, or distributor-less ignition system
  Many automobile engines now use a distributor-less ignition
system, or direct-ignition system, in which a high-voltage pulse
is directly applied to coils that sit on top of the spark plugs
(known as coil-on-plug). The major components of these systems
are a coil pack, an ignition module, a crankshaft reluctor ring,
a magnetic sensor, and an electronic control module.
Other systems dispense with the distributor and coil and use
special spark plugs which each contain their own coil
(Direct Ignition). This means high voltages are not routed all
over the engine, but are instead created at the point at which
they are needed. Such designs offer potentially much greater
reliability than conventional arrangements.
The Insight engine employs a direct ignition system similar to
those used on the Honda S2000 and the 1999 Odyssey. Separate
ignition coils for each cylinder are located directly above
the spark plugs.- Hide quoted text -
- Show quoted text -

Your original post said "direct INJECTION" not "direct IGNITION."
I've never heard of a distributorless ignition called a "direct
ignition" although I guess it kind of makes sense for a coil-on-plug
type setup.  Now direct INJECTION refers to something completely
different, as I described in my post.  Generally used on Diesel
engines although I have heard that some mfgrs. have or will introduce
it on gas engines as well.
nate

here's more reading for you to get you started:

http://en.wikipedia.org/wiki/Gasoline_direct_injection

that article seems to imply that the throttle plate is done away with;
I'm not certain that that is done in all implementations, but it's
certainly possible. Basically the engine would look like a Diesel
engine, but it would run on gasoline and have spark plugs.

nate

[RT]

On Tue, 15 Jul 2008 23:34:01 -0700 (PDT), Built_Well

Post by Built_Well

Post by Nate Nagel

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine. It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.
What you are describing is a "distributorless ignition."
nate

============================================
Very good information. I enjoyed reading it, and you're
right that the Camry does not inject fuel into the combustion
chamber but into the "antechamber" in the cylinder head that
comes just before the valve. That's what the manual's diagram
seems to show anyway.
But the 2AZ-FE /is/ a Direct Injection System. Here's a quote

No, it's not.
Direct injection is just now starting to be used in some European
cars. They're need for fuel efficiency is a lot higher.

Post by Built_Well
"A DIS (Direct Ignition System) has been adopted. The DIS improves
the ignition timing accuracy, reduces high-voltage loss, and
enhances the overall reliability of the ignition system by
eliminating the distributor. The DIS in this engine is an
independent ignition system which has one ignition coil (with
igniter) for each cylinder."

Direct ignition is pretty much common on any car these days.

[Dyno]

Post by RT
On Tue, 15 Jul 2008 23:34:01 -0700 (PDT), Built_Well

Post by Built_Well

Post by Nate Nagel

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine. It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.
What you are describing is a "distributorless ignition."
nate

============================================
Very good information. I enjoyed reading it, and you're
right that the Camry does not inject fuel into the combustion
chamber but into the "antechamber" in the cylinder head that
comes just before the valve. That's what the manual's diagram
seems to show anyway.
But the 2AZ-FE /is/ a Direct Injection System. Here's a quote

No, it's not.
Direct injection is just now starting to be used in some European
cars. They're need for fuel efficiency is a lot higher.

It is available in the US in the Mazdaspeed 3, Mazdaspeed 6 and the
Mazda CX7.

[Ray O]

Post by Built_Well

Post by Nate Nagel

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine. It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.
What you are describing is a "distributorless ignition."
nate

============================================
Very good information. I enjoyed reading it, and you're
right that the Camry does not inject fuel into the combustion
chamber but into the "antechamber" in the cylinder head that
comes just before the valve. That's what the manual's diagram
seems to show anyway.
But the 2AZ-FE /is/ a Direct Injection System. Here's a quote
"A DIS (Direct Ignition System) has been adopted. The DIS improves
the ignition timing accuracy, reduces high-voltage loss, and
enhances the overall reliability of the ignition system by
eliminating the distributor. The DIS in this engine is an
independent ignition system which has one ignition coil (with
igniter) for each cylinder."

As Nate pointed out, you appear to be confusing "injection" with "ignition."
Direct injection means that the fuel is injected directly into the
combustion chamber, and the cylinder head has another opening for the fuel
injector instead of injecting the fuel into the intake runner (what you
called the "antechamber." Injecting the fuel directly into the combustion
chamber requires much higher pressure to atomize the fuel in the higher
pressures within the combustion chamber.

Direct ignition has been around for over 15 years.

[EdV]

Post by Nate Nagel

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine. It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.

So its like a turbo charger? how is the pressure of the fuel
increased? and the pressure is increased when the liquid fuel is
already in vapor stage right? Isn't it necessary to cool down the
temperature of the high pressure vapor fuel before directly injecting
them into the combustion chamber.. like the purpose of an intercooler
for a turbo system. thanks!

[Steve W.]

Post by EdV

Post by Nate Nagel

Is the 2AZ-FE considered a direct injectin engine?

No

============= The 2AZ-FE is a direct injection engine. It does
not use a mechanical distributor, and the engine does use a
crankshaft sensor and a camshaft sensor, among other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion
chamber rather than into the intake runner or a throttle body.

So its like a turbo charger?

Nope.

Post by EdV
how is the pressure of the fuel increased?

Straight out of the fuel pump.

Post by EdV
the pressure is increased when the liquid fuel is already in vapor
stage right?

No, Liquid fuel gets injected directly into the cylinder. Unlike the
common port injection systems where the fuel gets injected into the
intake runner just behind the intake valve.

Post by EdV
Isn't it necessary to cool down the temperature of the high pressure
vapor fuel before directly injecting them into the combustion chamber?

No vapor injected on any modern fuel injection system. Even the
turbocharged systems only cool the air after it goes through the turbo.
None of them inject fuel until it hits the intake runner.

like the purpose of an intercooler for a turbo system. thanks!

The intercooler only cools the air itself. Nothing more.

[N8N]

Post by EdV

Post by Nate Nagel

Post by Built_Well

Is the 2AZ-FE considered a direct injectin engine?

No

=============
The 2AZ-FE is a direct injection engine.  It does not
use a mechanical distributor, and the engine does
use a crankshaft sensor and a camshaft sensor, among
other things.

"direct injection" typically refers to a very high pressure fuel
injection system that injects fuel directly into the combustion chamber
rather than into the intake runner or a throttle body.

So its like a turbo charger? how is the pressure of the fuel
increased? and the pressure is increased when the liquid fuel is
already in vapor stage right? Isn't it necessary to cool down the
temperature of the high pressure vapor fuel before directly injecting
them into the combustion chamber.. like the purpose of an intercooler
for a turbo system. thanks!- Hide quoted text -

Think Diesel engine. Bigass mechanical pump driven by the engine.
No, it doesn't pressurize the intake air, but the fuel has to be
pressurized to significantly more than the normal 50-100 PSI because
it's being sprayed into the compressed air in the chamber rather than
into the intake, where it's spraying into air that's at atmospheric
(or less, under part throttle - or slightly more, in a turbo/
supercharged engine on boost) pressure.

nate

[Ed White]

"N8N" <***@hotmail.com> wrote in message news:1e2c20ad-c15c-46c1-bd94-***@79g2000hsk.googlegroups.com...
On Jul 16, 12:38 pm, EdV <***@hotmail.com> wrote:

Think Diesel engine. Bigass mechanical pump driven by the engine.
No, it doesn't pressurize the intake air, but the fuel has to be
pressurized to significantly more than the normal 50-100 PSI because
it's being sprayed into the compressed air in the chamber rather than
into the intake, where it's spraying into air that's at atmospheric
(or less, under part throttle - or slightly more, in a turbo/
supercharged engine on boost) pressure.

As might be expected wikkipedia has a description - see
http://en.wikipedia.org/wiki/Gasoline_direct_injection . Other interesting
references:

http://www.greencarcongress.com/2005/12/wards_10_best_h.html
http://www.brunel.ac.uk/about/acad/sed/sedres/ee/cerg/recent/dige/

Ed

[Hachiroku ハチロク]

Post by Built_Well
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."

Yeah, that's the valve cover...

Post by Built_Well
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

Toyotas have been using aluminum heads for as long as I can remember. My
first Corolla, a '74, had an iron block and aluminum heads, which worked
well for them, but was a fatal combination for certain Chevy (VEGA) models...

[C. E. White]

Post by Hachiroku ハチロク

Post by Built_Well
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."

Yeah, that's the valve cover...

Post by Built_Well
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

Toyotas have been using aluminum heads for as long as I can
remember. My
first Corolla, a '74, had an iron block and aluminum heads, which worked
well for them, but was a fatal combination for certain Chevy (VEGA) models...

Actually Vegas had aluminum blocks and cast iron heads! One of the
stangest combinations ever. The original Vega block was the linerless
aluminum type and was die case with an open top deck. The aluminum
alloy had a lot of silicon in it .The theory was that the aluminunm
would wear away slightly, exposing the silicon surface, which would
prevent (or at least slow down) further bore wear. The block was very
light and not particulalry stiff which is why they used a cast iron
cylinder head to provide the stiffness absent from the block. I
suppose the test engines all worked well. Unfortunately, in the real
world, things did not work so well. The whimpy blocks couldn't take
any "normal" abuse. The slightest overheating would lead to rapid bore
wear and significant oil consumption. Hard driving would cause block
distortions which also led to rapid bore wear and significant oil
consumption. Poor maintenance practices led to rapid bore wear and
significant oil consumption. Etc. Essentially driving the car led to
rapid bore wear and significant oil consumption. But it often was not
much of a problem since rust usually ate the body away before oil
consumption was too bad. Body rustwas not a problem restricted to
Vegas by the way. Toyotas of the era were at least as prone to rusting
away.

BTW, Porsche and Mercedes use the linerless aluminum blocks that GM
tried on he Vega. But even today, you don't want to overheat an engine
using that technology.

Ed

[N8N]

Post by C. E. White

Post by Hachiroku ハチロク

Post by Built_Well
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."

Yeah, that's the valve cover...

Post by Built_Well
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

Toyotas have been using aluminum heads for as long as I can
remember. My
first Corolla, a '74, had an iron block and aluminum heads, which worked
well for them, but was a fatal combination for certain Chevy (VEGA) models...

Actually Vegas had aluminum blocks and cast iron heads! One of the
stangest combinations ever. The original Vega block was the linerless
aluminum type and was die case with an open top deck. The aluminum
alloy had a lot of silicon in it .The theory was that the aluminunm
would wear away slightly, exposing the silicon surface, which would
prevent (or at least slow down) further bore wear. The block was very
light and not particulalry stiff which is why they used a cast iron
cylinder head to provide the stiffness absent from the block. I
suppose the test engines all worked well. Unfortunately, in the real
world, things did not work so well. The whimpy blocks couldn't take
any "normal" abuse. The slightest overheating would lead to rapid bore
wear and significant oil consumption. Hard driving would cause block
distortions which also led to rapid bore wear and significant oil
consumption. Poor maintenance practices led to rapid bore wear and
significant oil consumption. Etc. Essentially driving the car led to
rapid bore wear and significant oil consumption. But it often was not
much of a problem since rust usually ate the body away before oil
consumption was too bad. Body rustwas not a problem restricted to
Vegas by the way. Toyotas of the era were at least as prone to rusting
away.
BTW, Porsche and Mercedes use the linerless aluminum blocks that GM
tried on he Vega. But even today, you don't want to overheat an engine
using that technology.
Ed

Thanks for confirming that my memory isn't completely shot :)

FWIW the all-aluminum engine in my 944 leaks more oil than it burns
AFAICT. I seem to have a penchant for attracting vehicles that aren't
known for gasket integrity :(

Rust seems to be a common theme with cars from the mid-70s and older.
The same neighbors that had the Vega also had a Volare wagon, the
front fenders were rusted through in only a couple of years. My dad's
Oldsmobile fared a little better, but it still had rusty fenders,
possibly because of some collision repair early in its life (was
sideswiped in a snowstorm on a windy country road by another driver
who lost control of her car) Once the Germans started using
galvanized body panels and that waxy undercoating the problems pretty
much went away (my mom's Golf lasted almost 20 years in semi-rural PA
before any significant corrosion showed up) I don't know about newer
American cars but I would assume that they've taken similar measures.

nate

[Hachiroku ハチロク]

Post by N8N

Post by C. E. White

Post by Hachiroku ハチロク

Post by Built_Well
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."

Yeah, that's the valve cover...

Post by Built_Well
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

Toyotas have been using aluminum heads for as long as I can
remember. My
first Corolla, a '74, had an iron block and aluminum heads, which worked
well for them, but was a fatal combination for certain Chevy (VEGA) models...

Actually Vegas had aluminum blocks and cast iron heads! One of the
stangest combinations ever. The original Vega block was the linerless
aluminum type and was die case with an open top deck.

<SNIP!>

Post by N8N

Post by C. E. White
Ed

Thanks for confirming that my memory isn't completely shot :)
FWIW the all-aluminum engine in my 944 leaks more oil than it burns
AFAICT. I seem to have a penchant for attracting vehicles that aren't
known for gasket integrity :(
Rust seems to be a common theme with cars from the mid-70s and older.
The same neighbors that had the Vega also had a Volare wagon, the
front fenders were rusted through in only a couple of years. My dad's
Oldsmobile fared a little better, but it still had rusty fenders,
possibly because of some collision repair early in its life (was
sideswiped in a snowstorm on a windy country road by another driver
who lost control of her car) Once the Germans started using
galvanized body panels and that waxy undercoating the problems pretty
much went away (my mom's Golf lasted almost 20 years in semi-rural PA
before any significant corrosion showed up) I don't know about newer
American cars but I would assume that they've taken similar measures.
nate

And, thanks to both of you for correcting me! I knew an iron
block/aluminum head works, since Toyota did it for so long, but I had
forgotten the reversal on the Vega. Like nate said, nice little car, but
what an abortion! If chevy had gotten it right it would have been an
import fighter for sure. Looks, OK handling, etc.

The few who got the Cosworth version were the lucky ones!

[Steve W.]

Post by Hachiroku ハチロク

Post by N8N

Post by C. E. White

Post by Hachiroku ハチロク

Post by Built_Well
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."

Yeah, that's the valve cover...

Post by Built_Well
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

Toyotas have been using aluminum heads for as long as I can
remember. My
first Corolla, a '74, had an iron block and aluminum heads, which worked
well for them, but was a fatal combination for certain Chevy (VEGA) models...

Actually Vegas had aluminum blocks and cast iron heads! One of the
stangest combinations ever. The original Vega block was the linerless
aluminum type and was die case with an open top deck.

<SNIP!>

Post by N8N

Post by C. E. White
Ed

Thanks for confirming that my memory isn't completely shot :)
FWIW the all-aluminum engine in my 944 leaks more oil than it burns
AFAICT. I seem to have a penchant for attracting vehicles that aren't
known for gasket integrity :(
Rust seems to be a common theme with cars from the mid-70s and older.
The same neighbors that had the Vega also had a Volare wagon, the
front fenders were rusted through in only a couple of years. My dad's
Oldsmobile fared a little better, but it still had rusty fenders,
possibly because of some collision repair early in its life (was
sideswiped in a snowstorm on a windy country road by another driver
who lost control of her car) Once the Germans started using
galvanized body panels and that waxy undercoating the problems pretty
much went away (my mom's Golf lasted almost 20 years in semi-rural PA
before any significant corrosion showed up) I don't know about newer
American cars but I would assume that they've taken similar measures.
nate

And, thanks to both of you for correcting me! I knew an iron
block/aluminum head works, since Toyota did it for so long, but I had
forgotten the reversal on the Vega. Like nate said, nice little car, but
what an abortion! If chevy had gotten it right it would have been an
import fighter for sure. Looks, OK handling, etc.
The few who got the Cosworth version were the lucky ones!

Considering that the Vega was an imported design (Opel) It wasn't a bad
car. Between my uncles and closer family we owned about 8 of them (and
more than a couple Monzas as well). The later Durabilt engines with the
steel liners held up pretty well. The front subframe to body plates is
the place to look for real rot on them. If it's gone walk away unless
the rest of the body is mint.

[Hachiroku ハチロク]

Post by Steve W.
(and
more than a couple Monzas as well).

Friend of mine had a Monza..the one with the 305!!!
HOLY CRAP!!!!
And because of Federal law, it only had an 85 MPH speedo!

[Steve W.]

Post by Hachiroku ハチロク

Post by Steve W.
(and
more than a couple Monzas as well).

Friend of mine had a Monza..the one with the 305!!!
HOLY CRAP!!!!
And because of Federal law, it only had an 85 MPH speedo!

My last Monza had a slightly warm 327 in it... It also had a 120 MPH
speedo and could BURY it at will!!!!

I just got rid of my last H body last week. I'll probably regret it. It
was an Olds Starfire GT. It started life as a 4 speed 231 V6 car. It
left here with a turbocharged 231 from a GNX in it. Still a 4 speed but
with a full frame kit. It was a very fun car to drive but I need to
clear out some of the toys.

[Hachiroku ハチロク]

but I need to clear out some of the toys.

NEVER!!!!

[Nate Nagel]

Post by Steve W.

Post by Hachiroku ハチロク

(and more than a couple Monzas as well).

Friend of mine had a Monza..the one with the 305!!!
HOLY CRAP!!!! And because of Federal law, it only had an 85 MPH speedo!

My last Monza had a slightly warm 327 in it... It also had a 120 MPH
speedo and could BURY it at will!!!!
I just got rid of my last H body last week. I'll probably regret it. It
was an Olds Starfire GT. It started life as a 4 speed 231 V6 car. It
left here with a turbocharged 231 from a GNX in it. Still a 4 speed but
with a full frame kit. It was a very fun car to drive but I need to
clear out some of the toys.

That sounds like a fun ride, even if it makes nasty blatty V-6 noises.
I gotta ask, what are your other toys if that one isn't fun enough to
make the cut?

nate

(gonna be driving my '55 soon, I swear... I'm going through V-8 withdrawal)

[Steve]

Post by C. E. White

Post by Hachiroku ハチロク
Toyotas have been using aluminum heads for as long as I can remember. My
first Corolla, a '74, had an iron block and aluminum heads, which worked
well for them, but was a fatal combination for certain Chevy (VEGA) models...

Actually Vegas had aluminum blocks and cast iron heads! One of the
stangest combinations ever.

Similar combination to the '62 Chrysler 225 slant-6 (aluminum block
version). Cost and manufacturing considerations necessitated the use of
a common iron head on both the die-cast aluminum block and the
simultaneously-produced iron block version of the 225. The aluminum 225,
unlike the first iteration of the Vega engine, did have cylinder liners.
Both were, as you noted, open-deck designs with free-standing cylinder
bores.

Later, the notorious Cadillac HT-4100 4.1L v8 of the 80s used cast iron
heads on an aluminum block also. The failure of the 4100 really doesn't
say anything bad about iron heads on aluminum blocks, per se. The
slant-6 had relatively little trouble, although people who build them
today for restoration (and occasional racing- the bare block can be
hauled around one-handed!) note that it doesn't have a lot of margin for
high cylinder pressures and doesn't take well to much boost or any
detonation. But the stock ones held up just fine, and there are a
surprising number out there still running around (sometimes with the
owner completely unaware that its an aluminum engine). But conceptually,
it really is a little backwards to build a light aluminum block and then
penalize it with a pig of an iron head. If you need iron, it makes more
sense to use it in the BLOCK where the extra strength is most needed,
and that's why there are so many iron block/aluminum head engines still
in production. And looking back to the first poster quoted above, I
can't think of ANY iron block/aluminum head engine that proved to be a
"fatal combination." I know a lot of people believed it was going to be
awful when they first started appearing in the 70s, but in practice it
worked just fine with the correct choice of head gasket material to
allow for the differential expansion. Heck, my wife's iron
block/aluminum head Chrysler 3.5 has 260,000 miles and has never had the
heads off (or anything deeper in than the intake plenum gasket, for that
matter).


My memory of the Vega's problems pretty much agrees with yours- the main
flaw was the lack of rigidity of the block itself, allowing the
cylinders to "go egg shaped" with the slightest overheating (or even
normal spirited/agressive driving), resulting in huge oil consumption
and of course power loss.

[N8N]

Post by Hachiroku ハチロク

Post by Built_Well
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."

Yeah, that's the valve cover...

Post by Built_Well
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

Toyotas have been using aluminum heads for as long as I can remember. My
first Corolla, a '74, had an iron block and aluminum heads, which worked
well for them, but was a fatal combination for certain Chevy (VEGA) models...

IIRC it was backwards... the Vega had an aluminum block with an iron
head. This was back in the day before the Nikasil and similar
processes were perfected, and I am guessing that simple piston/bore
wear was the cause of most of the mosquito fogging action that the
Vegas were famous for. I remember when I was a kid the neighbors
across the street had one and it would lay one heck of a smokescreen.
Was an attractively styled little car but the engines were definitely
a weak link.

I believe that John DeLorean addressed some of the engineering mishaps
in the Vega's development in his book, but it's been years since I
read it so I'm a little furry on the details.

nate

[Ray O]

Post by Built_Well
Gonna write this stuff down and post it so I don't lose it. Had
to wade through a lot of pages to find it. The 5th Generation Camry's
2AZ-FE engine (an advanced powerplant, by the way) is
the same engine that was used in the '01 Highlander SUV.
5th Generation Camrys cover Model Years '02 - '06.

This stuff is interesting if you have an initerest and understanding of
engines, but otherwise, it is not that helpful for the average
do-it-yourselfer.

Post by Built_Well
The cylinder block is made of aluminum alloy. It uses aluminum
pistons, high-strength steel connecting rods and caps, forged steel
crankshaft, and, IIRC aluminum camshafts. The VVT-i only works
on the intake camshaft, not the exhaust camshaft. It varies
the timing of the intake valves. There are two intake valves per
cylinder and two exhaust valves per cylinder. Having two of
each increases the total port area, so more air can flow into
and out of the combustion chamber. As the manual's authors
write, "Intake and exhaust efficiency has been increased due
to the larger total port areas."
The cylinder head cover (not to be confused with the cylinder
head) is made of magnesium alloy for lighter weight. I think
cylinder head cover is synonymous with "valve cover," but the
Camry manual refers to it as the "cylinder head cover."

Toyota calls valve covers "cylinder head covers."

Post by Built_Well
Since the manual doesn't mention what the cylinder head, itself,
is made of, I will assume iron, but just an assumption.

The head is also made of aluminum alloy.

Post by Built_Well
The cylinder head gasket, used between the aluminum engine block
and the (iron?) cylinder head is a steel-laminate type of
material. Any concern about electrolysis taking place between
the steel-laminate and aluminum?

No concerns about electrolysis taking place between the head gasket and
aluminum, but you should stick with genuine Toyota coolant.

Post by Built_Well
When the service and repair manual says the dry weight of the
engine is 267 pounds, does that include the crankcase, crank,
cylinder head, and valve head with camshafts--or does the
weight only include the engine block without crankcase
and cyclinder head, etc.?

As Ed mentioned, "dry" means without fluids like oil and coolant. The
weight is for the long block, which is basically the entire engine minus PS
pump, AC compressor, & alternator.

Post by Built_Well
The crankshaft and camshafts are connected by a timing chain,
not a belt.

Toyota has started to go back to timing chains on new engines.

Post by Built_Well
The oil pump is located behind the timing chain cover at the
front bottom of the engine, even lower than the crankshaft.

This is a common arrangement for Toyotas.

The oil

Post by Built_Well
pump has
its own short section of chain that's connected to the
crankshaft. Couldn't tell from the picture if this is a second,
dedicated chain, or just part of the larger chain that ascends to
the camshafts. Double overhead cams, don't ya know (DOHC) :-)
If I had to guess, I'd say the oil pump has its own dedicated
short chain that's separate from the timing chain, ie., camshaft
chain..

F.Y.I., an engine with 4 camshafts like a Toyota V6 or V8 is also referred
to as double overhead cams, or DOHC because the nomenclature refers to the
cams over each head.

Some older Toyota engines (and current domestic engines) have a single
overhead cam, or SOHC.

[Built_Well]

Post by Ray O
Some older Toyota engines (and current domestic engines) have
a single overhead cam, or SOHC.

========

Single overhead cam (SOHC)!!!! Well, I guess that's better
than using pushrods and rollers.

[Steve W.]

Post by Built_Well

Post by Ray O
Some older Toyota engines (and current domestic engines) have
a single overhead cam, or SOHC.

========
Single overhead cam (SOHC)!!!! Well, I guess that's better
than using pushrods and rollers.

WHY?
Push rod engines have been around a LONG time. Toyota even agrees as
they built more than a few. (take a look under the Tundra V8s hood)

[Ray O]

Post by Built_Well

Post by Ray O
Some older Toyota engines (and current domestic engines) have
a single overhead cam, or SOHC.

========
Single overhead cam (SOHC)!!!! Well, I guess that's better
than using pushrods and rollers.

WHY?
Push rod engines have been around a LONG time. Toyota even agrees as they
built more than a few. (take a look under the Tundra V8s hood)
--
Steve W.

The production Tundra's 4.7 and 5.7 liter V8's are both DOHC designs. The
NASCAR Craftsman Series "Tundras" use pushrod engines ;-)

AFAIK, Toyota does not sell any pushrod engines in North America any more.

People have probably spent millions of hours debating the benefits of
pushrods vs OHC engines, and IMHO, each style has benefits over the other in
certain applications.

[N8N]

Post by Built_Well

Post by Ray O
Some older Toyota engines (and current domestic engines) have
a single overhead cam, or SOHC.

========
Single overhead cam (SOHC)!!!!  Well, I guess that's better
than using pushrods and rollers.

WHY?
Push rod engines have been around a LONG time. Toyota even agrees as they
built more than a few. (take a look under the Tundra V8s hood)
--
Steve W.

The production Tundra's 4.7 and 5.7 liter V8's are both DOHC designs.  The
NASCAR Craftsman Series "Tundras" use pushrod engines ;-)
AFAIK, Toyota does not sell any pushrod engines in North America any more.
People have probably spent millions of hours debating the benefits of
pushrods vs OHC engines, and IMHO, each style has benefits over the other in
certain applications.

The main advantage to a pushrod engine is packaging. I believe that
was one of the reasons given for GM for sticking with a pushrod design
for their newest small-block V-8s; they needed them to fit under the
low hoodline of a Corvette.

nate

[Built_Well]

N8N, sometime you ought to read Joey's long political rantings
on alt.autos.TOYOTA . It seems all Joey does all day
is post politics in a Toyota newsgroup and attack Jeff.

[Steve]

Post by Built_Well

Post by Ray O
Some older Toyota engines (and current domestic engines) have
a single overhead cam, or SOHC.

========
Single overhead cam (SOHC)!!!! Well, I guess that's better
than using pushrods and rollers.

Dumb statement.

V-configuration pushrod engines can be significantly more compact than
OHC designs because the cam is tucked between the banks rather than
having a cam hanging out over the bank making the "V" both taller and
wider. Plus the cam timing wanders less because the chain is shorter.
And when there are other engine architecture considerations that make it
unnecessary to wind them tighter than 6000 RPM, overhead cams don't have
any advantage. That's why so many pushrod engines, ranging from
pedestrian GM v8s and v6 to the Corvette ZO-6 and Chrysler SRT-8 Hemis
are still being designed and built.

[JoeSpareBedroom]

Post by Built_Well
Gonna write this stuff down and post it so I don't lose it.

Of course, you could've just written it down in a text document and saved it
rather than posted it, assuming the actual purpose was to not lose it.

[Built_Well]

Post by JoeSpareBedroom

Post by Built_Well
Gonna write this stuff down and post it so I don't lose it.
=============

Of course, you could've just written it down in a text document and saved it
rather than posted it, assuming the actual purpose was to not lose it.

=================

Joey, you should take a hint from Jeff Strickland. He's
much more polite and together than you.

[JoeSpareBedroom]

Post by Built_Well

Post by JoeSpareBedroom

Post by Built_Well
Gonna write this stuff down and post it so I don't lose it.
=============

Of course, you could've just written it down in a text document and saved it
rather than posted it, assuming the actual purpose was to not lose it.

=================
Joey, you should take a hint from Jeff Strickland. He's
much more polite and together than you.

Clarity of purpose is a good thing. Try it sometime.

[disston]

I think it was Buick. Had an Aluminium engine in something like '62.
V8, I think it was 300 ci. I did a brake job on one of those cars once
and really liked driving it. So when I gave it back to the girl that
owneed it I tried to explain that it was of utmost concern that this
car NEVER be over heated. Always check coolant and have a GOOD
radiatoer, fan belt, water pump, etc....One year later she was trying
to sell it to me because "We think it's only the head gasket". Right.
Aluminium warps really good.

disston

[C. E. White]

Post by disston
I think it was Buick. Had an Aluminium engine in something like '62.
V8, I think it was 300 ci. I did a brake job on one of those cars once
and really liked driving it. So when I gave it back to the girl that
owneed it I tried to explain that it was of utmost concern that this
car NEVER be over heated. Always check coolant and have a GOOD
radiatoer, fan belt, water pump, etc....One year later she was
trying
to sell it to me because "We think it's only the head gasket".
Right.
Aluminium warps really good.

The engine was 215 cubic inches and had cast iron liners. GM sold the
tooling to British Leyland and they continued to produce it for years.
I think Ford finally stopped producing it when they bought Land Rover
(but according to wikipedia, it is still in production at third
party). Oldsmobile sold a turbocharged version. It was sold in various
Buick, Oldsmobile, and Pontiac intermediate sized cars (included the
Tempest that used a transaxle with IRS).

See http://en.wikipedia.org/wiki/Buick_V8_engine and
http://en.wikipedia.org/wiki/Rover_V8_engine

Ed

[EdV]

The 2AZ-FE has a variant 2AZ-FXE for hybrid cars.

By the way, the supercharged 2AZ-FE's found on some of the Scion tC,
are there other modifications on the engine or just added the super
charger? Would you be able to fit a supercharger on a camry, rav4 or
highlander?

[C. E. White]

Post by EdV
The 2AZ-FE has a variant 2AZ-FXE for hybrid cars.
By the way, the supercharged 2AZ-FE's found on some of the Scion tC,
are there other modifications on the engine or just added the super
charger? Would you be able to fit a supercharger on a camry, rav4 or
highlander?

Not sure. I would think that you could given the proper kit.

See

http://en.wikipedia.org/wiki/Toyota_AZ_engine#2AZ-FE
http://www.toyotanation.com/forum/showthread.php?t=201074
http://www.toyotanation.com/forum/archive/topic/111394-1.html

Ed

[j***@hotmail.com]

Hee hee hee. 2AZFE "an advanced powerplant?" that's a good one.
Checkout the Audi FSI 2.0T for an advanced design with a flat torque
curve from 2000-5000 RPMs.

Gonna write this stuff down and post it so I don't lose it.  Had
to wade through a lot of pages to find it.  The 5th Generation Camry's
2AZ-FE engine (an advanced powerplant, by the way) is
the same engine that was used in the '01 Highlander SUV.
5th Generation Camrys cover Model Years '02 - '06.

[EdV]

Post by j***@hotmail.com
Hee hee hee. 2AZFE "an advanced powerplant?" that's a good one.
Checkout the Audi FSI 2.0T for an advanced design with a flat torque
curve from 2000-5000 RPMs.

IIRC, The flat torque is because of the CVT transmission design and
not the engine. I could be wrong.
.

[N8N]

Post by EdV

Post by j***@hotmail.com
Checkout the Audi FSI 2.0T for an advanced design with a flat torque
curve from 2000-5000 RPMs.

IIRC, The flat torque is because of the CVT transmission design and
not the engine. I could be wrong.
.

The old 1.8T had an essentially flat torque curve over the same rev
range and was only available with conventional transmissions. I
wasn't aware that Audi had a CVT yet, although I have missed stuff
before. I thought their new high end transmission was the dual-clutch
deal?

nate

[RT]

Post by EdV

Post by j***@hotmail.com
Hee hee hee. 2AZFE "an advanced powerplant?" that's a good one.
Checkout the Audi FSI 2.0T for an advanced design with a flat torque
curve from 2000-5000 RPMs.

IIRC, The flat torque is because of the CVT transmission design and
not the engine. I could be wrong.
.

A transmission has nothing to do with torque output of an engine.
A CVT is able to keep the rpms at max torque at all times while
accelerating.

[Dyno]

Post by RT

Post by EdV

Post by j***@hotmail.com
Hee hee hee. 2AZFE "an advanced powerplant?" that's a good one.
Checkout the Audi FSI 2.0T for an advanced design with a flat torque
curve from 2000-5000 RPMs.

IIRC, The flat torque is because of the CVT transmission design and
not the engine. I could be wrong.
.

A transmission has nothing to do with torque output of an engine.
A CVT is able to keep the rpms at max torque at all times while
accelerating.

Max HP speed will give best acceleration.

[Scott Dorsey]

Post by RT

Post by EdV

Post by j***@hotmail.com
Hee hee hee. 2AZFE "an advanced powerplant?" that's a good one.
Checkout the Audi FSI 2.0T for an advanced design with a flat torque
curve from 2000-5000 RPMs.

IIRC, The flat torque is because of the CVT transmission design and
not the engine. I could be wrong.
.

A transmission has nothing to do with torque output of an engine.
A CVT is able to keep the rpms at max torque at all times while
accelerating.

Right. Correspondingly, if you have a CVT, you can get away with an
engine that has high torque in a very narrow speed range, whereas with
a conventional transmission the engine has to be able to provide good
torque over a wider range of speeds. (ie. the torque curve has to have
a much wider peak on it).
--scott

[EdV]

This is how I understand GDI (gasoline DIRECT injection), feel free to
correct my mistake

Fuel and air mixture are injected in some kind of pressure tank where
the pressure is increased, by compressing the mixture I suppose. At
this stage the ratio of the fuel and air is adjusted for optimum burn.

This pressure tank sometimes called as a *common rail*? has a nozzle
that will release the pressurized fuel-air mixture directly into the
chamber chamber via the intake valves. This high pressure coupled with
optimum ratio allows the engine to run more fuel efficiently and, of
course, more powerful. The VVTi (toyota) will then adjust the opening
of the valves whether to inject the mixture during the intake stroke
or slightly delayed.

[C. E. White]

Post by EdV
This is how I understand GDI (gasoline DIRECT injection), feel free to
correct my mistake
Fuel and air mixture are injected in some kind of pressure tank where
the pressure is increased, by compressing the mixture I suppose. At
this stage the ratio of the fuel and air is adjusted for optimum burn.
This pressure tank sometimes called as a *common rail*? has a nozzle
that will release the pressurized fuel-air mixture directly into the
chamber chamber via the intake valves. This high pressure coupled with
optimum ratio allows the engine to run more fuel efficiently and, of
course, more powerful. The VVTi (toyota) will then adjust the
opening
of the valves whether to inject the mixture during the intake stroke
or slightly delayed.

In the direct engine engines I have researched, there is no tank that
mixes the fuel and air. There is an injector in the combustion chamber
instead of in the intake tract before the intake valves. Air is
admitted into the combustion chamber by the valves. Fuel is injected
directly into the combustion chamber, instead of being mixed with the
air in the intake tract before the intake valves. By injecting the
fuel directly into the combustion chamber, you can create a
"stratified charge." In other words a non-uniform mixture of gasoline
vapor and air. Gasoline is very difficult to ignite if you don't have
the proper air/fuel mixture. By creating a stratified charge, you can
have a proper A/F mixture in the area of the spark plug and a lean
mixture everywhere else. The spark plug can then easily ignite the
proper mixture in the area of the spark plug and this in turn will
burn the leaner mixture elsewhere in the combustion chamber. This
allows an overall leaner mixture to be burned, resulting in higher
efficiency. Chrysler tried this years ago with carbureted engines with
limited success (tried to manipulate the mixture with combustion
chamber and intact tract shape). Honda tried something a little
different with a three valve design in the late 70's (two "regular"
valves and one smaller valve to richen the mixture near the plug).
Neither worked very well. There are a lot of great claims being made
for direct injection engines. However, the direct injected manual
transmission Mazda 5 gets worse EPA gas mileage than the regular old 4
cylinder automatic Toyota RAV4 (which is larger and heavier...).

Ed

[EdV]

On Jul 18, 11:05 am, "C. E. White" <***@removemindspring.com>
wrote:
There is an injector in the combustion chamber

Post by C. E. White
instead of in the intake tract before the intake valves. Air is
admitted into the combustion chamber by the valves. Fuel is injected
directly into the combustion chamber, instead of being mixed with the
air in the intake tract before the intake valves.

Ahh, so the intake valves is just for the AIR and the injector for the
FUEL. no pre-mixing involved. The mixing occurs directly inside the
combustion chamber. The fuel is pressurized and not the air like in a
turbo setup. Thanks!

[Retired VIP]

Post by C. E. White
There is an injector in the combustion chamber

Post by C. E. White
instead of in the intake tract before the intake valves. Air is
admitted into the combustion chamber by the valves. Fuel is injected
directly into the combustion chamber, instead of being mixed with the
air in the intake tract before the intake valves.

Ahh, so the intake valves is just for the AIR and the injector for the
FUEL. no pre-mixing involved. The mixing occurs directly inside the
combustion chamber. The fuel is pressurized and not the air like in a
turbo setup. Thanks!

Yep, you got it Edv. But the fuel is injected into the combustion
chamber, not the intake manifold.

Of the three types of fuel injection, the direct injection has the
capability of being the most efficient. The air/fuel mixture can be
precisely adjusted for each individual cylinder and for each
individual power stroke.

Throttle body injection is the least precise of the three. It is
basically just a computer controlled carb that uses a injection jet
instead of a metering jet. It's better than a carburetor but not by
much.

Multi-port injection places one injector in the manifold runner to
each cylinder. This is a better scheme that allows more precision but
it is limited on how much the mixture can be leaned out before
pre-ignition occurs.

Direct injection allows placing a rich fuel/air mixture around the
sparkplug and a much leaner mixture in the rest of the cylinder. By
the time the flame front moves out to the rest of the cylinder, the
piston has moved past top dead center and the much faster burn rate of
a lean mixture won't hurt the engine.

I hope this helps and if I've gotten anything wrong in this, I'm sure
someone will correct me.

Jack

[EdV]

Post by Retired VIP

Post by C. E. White
There is an injector in the combustion chamber

Post by C. E. White
instead of in the intake tract before the intake valves. Air is
admitted into the combustion chamber by the valves. Fuel is injected
directly into the combustion chamber, instead of being mixed with the
air in the intake tract before the intake valves.

Ahh, so the intake valves is just for the AIR and the injector for the
FUEL. no pre-mixing involved. The mixing occurs directly inside the
combustion chamber. The fuel is pressurized and not the air like in a
turbo setup. Thanks!

Yep, you got it Edv. But the fuel is injected into the combustion
chamber, not the intake manifold.
Of the three types of fuel injection, the direct injection has the
capability of being the most efficient. The air/fuel mixture can be
precisely adjusted for each individual cylinder and for each
individual power stroke.
Throttle body injection is the least precise of the three. It is
basically just a computer controlled carb that uses a injection jet
instead of a metering jet. It's better than a carburetor but not by
much.
Multi-port injection places one injector in the manifold runner to
each cylinder. This is a better scheme that allows more precision but
it is limited on how much the mixture can be leaned out before
pre-ignition occurs.
Direct injection allows placing a rich fuel/air mixture around the
sparkplug and a much leaner mixture in the rest of the cylinder. By
the time the flame front moves out to the rest of the cylinder, the
piston has moved past top dead center and the much faster burn rate of
a lean mixture won't hurt the engine.
I hope this helps and if I've gotten anything wrong in this, I'm sure
someone will correct me.
Jack

Great! So this means its possible not to have VVTi and Direct
injection at the same time. The timing of the fuel comes from the
nozzle and not from the opening of the valves, although air enters
through the valves, its the fuel which is controlled and not the air.

[Retired VIP]

Post by EdV

Post by Retired VIP

Post by C. E. White
There is an injector in the combustion chamber

Direct injection allows placing a rich fuel/air mixture around the
sparkplug and a much leaner mixture in the rest of the cylinder. By
the time the flame front moves out to the rest of the cylinder, the
piston has moved past top dead center and the much faster burn rate of
a lean mixture won't hurt the engine.
I hope this helps and if I've gotten anything wrong in this, I'm sure
someone will correct me.
Jack

Great! So this means its possible not to have VVTi and Direct
injection at the same time. The timing of the fuel comes from the
nozzle and not from the opening of the valves, although air enters
through the valves, its the fuel which is controlled and not the air.

No, I think it would still be possible to use variable valve timing
and direct injection at the same time. The amount of fuel is
controlled by the engine computer based on info it gets from the O2
sensor, throttle position, RPM, etc. VVTi would still be a valid way
to increase engine efficiency by controlling the amount of air, that's
really all it controls with multi-port injection also.

Jack

[Leftie]

Post by Retired VIP

Post by EdV

Post by Retired VIP

Post by C. E. White
There is an injector in the combustion chamber

Direct injection allows placing a rich fuel/air mixture around the
sparkplug and a much leaner mixture in the rest of the cylinder. By
the time the flame front moves out to the rest of the cylinder, the
piston has moved past top dead center and the much faster burn rate of
a lean mixture won't hurt the engine.
I hope this helps and if I've gotten anything wrong in this, I'm sure
someone will correct me.
Jack

Great! So this means its possible not to have VVTi and Direct
injection at the same time. The timing of the fuel comes from the
nozzle and not from the opening of the valves, although air enters
through the valves, its the fuel which is controlled and not the air.

No, I think it would still be possible to use variable valve timing
and direct injection at the same time. The amount of fuel is
controlled by the engine computer based on info it gets from the O2
sensor, throttle position, RPM, etc. VVTi would still be a valid way
to increase engine efficiency by controlling the amount of air, that's
really all it controls with multi-port injection also.
Jack

I think you misread the post. He was saying it's possible to not
have both features, not that it's impossible to have both.

[Retired VIP]

Post by Leftie

Post by Retired VIP

Post by EdV

Post by Retired VIP

Post by C. E. White
There is an injector in the combustion chamber

Direct injection allows placing a rich fuel/air mixture around the
sparkplug and a much leaner mixture in the rest of the cylinder. By
the time the flame front moves out to the rest of the cylinder, the
piston has moved past top dead center and the much faster burn rate of
a lean mixture won't hurt the engine.
I hope this helps and if I've gotten anything wrong in this, I'm sure
someone will correct me.
Jack

Great! So this means its possible not to have VVTi and Direct
injection at the same time. The timing of the fuel comes from the
nozzle and not from the opening of the valves, although air enters
through the valves, its the fuel which is controlled and not the air.

No, I think it would still be possible to use variable valve timing
and direct injection at the same time. The amount of fuel is
controlled by the engine computer based on info it gets from the O2
sensor, throttle position, RPM, etc. VVTi would still be a valid way
to increase engine efficiency by controlling the amount of air, that's
really all it controls with multi-port injection also.
Jack

I think you misread the post. He was saying it's possible to not
have both features, not that it's impossible to have both.

You are right lefty. I did misread the OP's comments. Sorry and he
would be right. I guess I get in too much of a hurry sometimes.

Jack

[Leftie]

Post by Retired VIP

Post by Leftie

Post by Retired VIP

Post by EdV

Post by Retired VIP

Post by C. E. White
There is an injector in the combustion chamber

Direct injection allows placing a rich fuel/air mixture around the
sparkplug and a much leaner mixture in the rest of the cylinder. By
the time the flame front moves out to the rest of the cylinder, the
piston has moved past top dead center and the much faster burn rate of
a lean mixture won't hurt the engine.
I hope this helps and if I've gotten anything wrong in this, I'm sure
someone will correct me.
Jack

Great! So this means its possible not to have VVTi and Direct
injection at the same time. The timing of the fuel comes from the
nozzle and not from the opening of the valves, although air enters
through the valves, its the fuel which is controlled and not the air.

No, I think it would still be possible to use variable valve timing
and direct injection at the same time. The amount of fuel is
controlled by the engine computer based on info it gets from the O2
sensor, throttle position, RPM, etc. VVTi would still be a valid way
to increase engine efficiency by controlling the amount of air, that's
really all it controls with multi-port injection also.
Jack

I think you misread the post. He was saying it's possible to not
have both features, not that it's impossible to have both.

You are right lefty. I did misread the OP's comments. Sorry and he
would be right. I guess I get in too much of a hurry sometimes.
Jack

We all do that. The internet seems to induce a kind of Adult ADD -
we go too fast when reading and responding...

[j***@hotmail.com]

Using only half a set of variable valve timing (VVT) saves money.

Some manufacturers use it on the intake side, some on the exhaust
side. If VVT is used on the exhaust side then the engine should have
NO EGR valve. The timing will allow the exhaust gas to be sucked back
into the cylinder. So that's one advantage for exhaust side VVT.

Of course, real luxury car engines would have VVT on both intake and
exhaust. Not only that, for instance, accelerator pedals on some newer
BMWs use CONTINUOUSLY VARIABLE VALVE LIFT to control acceleration!
(What throttle valve?) That's another reason why I say Toyota Lexus
isn't worth the money unless you like the dolled-up look, which really
is fine.

Post by Built_Well
The VVT-i only works
on the intake camshaft, not the exhaust camshaft.  It varies
the timing of the intake valves.  There are two intake valves per
cylinder and two exhaust valves per cylinder.  Having two of
each increases the total port area, so more air can flow into
and out of the combustion chamber.  As the manual's authors
write, "Intake and exhaust efficiency has been increased due
to the larger total port areas."

[Steve]

Post by Built_Well
Gonna write this stuff down and post it so I don't lose it. Had
to wade through a lot of pages to find it. The 5th Generation Camry's
2AZ-FE engine (an advanced powerplant, by the way) is
the same engine that was used in the '01 Highlander SUV.
5th Generation Camrys cover Model Years '02 - '06.
The cylinder block is made of aluminum alloy. It uses aluminum
pistons, high-strength steel connecting rods and caps, forged steel
crankshaft, and, IIRC aluminum camshafts. The VVT-i only works
on the intake camshaft, not the exhaust camshaft. It varies
the timing of the intake valves. There are two intake valves per
cylinder and two exhaust valves per cylinder. Having two of
each increases the total port area, so more air can flow into
and out of the combustion chamber. As the manual's authors
write, "Intake and exhaust efficiency has been increased due
to the larger total port areas."

Advanced? Its an average modern v6. Apart from VVT, there's not a damn
thing to distinguish it from any other (and most others have VVT these
days, so even that's not distinguishing- some have VVT and cylinder
deactivation).

And if the hear really were iron, then it would be exactly as advanced
as the 1962 die-cast aluminum block/iron head slant-6.

[l***@gmail.com]

I just need the weigh of the botton end on head no timing cover block piston crank oil pan

[AMuzi]

Post by l***@gmail.com
I just need the weigh of the botton end on head no timing cover block piston crank oil pan

I have no idea but suppliers of rebuilt engines (who ship
them all day long) would know.

http://www.jisautoengine.com/to01caso2aen.html