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Author:
Date:
Subject:
N8N
2008-07-15 06:04:04
Re: Some details of the 2AZ-FE engine
On Jul 15, 10:41 am, Hachiroku ハチロク <[email protected]> wrote:
> On Mon, 14 Jul 2008 20:08:50 -0700, Built_Well wrote:
> > 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...
>
>
>
> > 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
Author:
Date:
Subject:
Ray O
2008-07-14 23:53:55
Re: Some details of the 2AZ-FE engine
"Built_Well" <[email protected]> wrote in message
news:97101848-da38-42b3-88d7-6dcb0def23b9@s50g2000hsb.googlegroups.com...
>
> 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.
>
> 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."
>
> 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.
>
> 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.
> 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.
> 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.
>
> 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
> 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.
--
Ray O
(correct punctuation to reply)
Author:
Date:
Subject:
Built_Well
2008-07-14 22:18:05
Re: Some details of the 2AZ-FE engine
Ray O wrote:
>
> 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.
Author:
Date:
Subject:
Steve W.
2008-07-15 01:26:03
Re: Some details of the 2AZ-FE engine
Built_Well wrote:
> Ray O wrote:
>> 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.
Author:
Date:
Subject:
Ray O
2008-07-15 00:54:37
Re: Some details of the 2AZ-FE engine
"Steve W." <[email protected]> wrote in message
news:g5hcd3$lmc$1@aioe.org...
> Built_Well wrote:
>> Ray O wrote:
>>> Some older Toyota engines (and current domestic engines) have
>>> a single overhead cam, or SOHC.
>> ========
>>
>> Single overhead cam (SOHC)!!!! Well, I guess that's better
>> than using pushrods and rollers.
>
> WHY?
> Push rod engines have been around a LONG time. Toyota even agrees as they
> built more than a few. (take a look under the Tundra V8s hood)
>
> --
> Steve W.
The production Tundra's 4.7 and 5.7 liter V8's are both DOHC designs. The
NASCAR Craftsman Series "Tundras" use pushrod engines ;-)
AFAIK, Toyota does not sell any pushrod engines in North America any more.
People have probably spent millions of hours debating the benefits of
pushrods vs OHC engines, and IMHO, each style has benefits over the other in
certain applications.
--
Ray O
(correct punctuation to reply)
Author:
Date:
Subject:
N8N
2008-07-15 06:18:13
Re: Some details of the 2AZ-FE engine
On Jul 15, 1:54 am, "Ray O" <rokigawaATtristarassociatesDOTcom> wrote:
> "Steve W." <[email protected]> wrote in message
>
> news:g5hcd3$lmc$1@aioe.org...
>
> > Built_Well wrote:
> >> Ray O wrote:
> >>> 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
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