Today's subject is an '82 Camaro with the infamous "Iron Duke" 4 banger and
appx 96,000 miles. Car ran great (80 mile round trip each day, no problems)
until it simply quit without warning one fine day on the interstate. A
compression test was performed and the engine has virtually *no* compression at
all (first cyl 8psi, 2nd thru 4th appx 12 psi, throttle wide open) which
ordinarily would lead one to suspect the timing chain except this engine
doesn't have a chain, it has gears, and the camshaft and valve gear are still
rotating when operating the starter. Can timing gears "skip time" like a timing
chain can? Could a blown head gasket or plugged exhaust system be to blame, or
perhaps something else? It's not my car, and I've never worked on one of these
engines before so any advice would be much appreciated. Also, the manual says
the cam has to be removed to change timing gears on this motor....is this true?
Much thanks for any help.
for e-mail, remove the obvious
DrivesaRec spilled my beer when they jumped on the table and proclaimed in
If it was a plugged exhaust, you would still have good compression. If it
was a blown head gasket, normally, only one or two would be low, and you
may have antifreeze in the oil.
I don't remember this engine for some reason, but do you have the ability
to check the timing marks on the gears? Someone (forget the manufacturer)
made some fiber composite gearing years ago that tended to shred...
My gut instinct is something along the lines of rings? Timing? But I have
been wrong a lot recently. <G>
Let us know what you find...
This engine has metal gears that last a VERY long time before they give up
hope. They rarely go bad. However, given the mileage, this is a possibility
(you don't state the mileage).
I'd start with all the basics as people have mentioned here.
I think you are thinking of the regular V8's on GM---they use nylon gears. We
did a 82 Celebrity (has the iron duke, just going the other way) and I remember
doing the gears on that car.
Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
'80 Carousel Red Turbo T/A, 26k orig.
'79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
'84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going....
'80 T/A project car...
The saga continues...
Finally got a look at this beatie yesterday, didn't have much time but was able
to do a first-hand compression test to verify what I was told. Results were:
Cyl 1: 12 psi
Cyl 2: 50 psi
Cyl 3: 32 psi
Cyl 4: 45 psi.
They're all low, but some are much low-er than others. Any ideas/suggestions as
to why that might be?
Tried to check the timing also, but at cranking speed there wasn't much to see.
Thanks again for any help....last stupid question from me, I promise....
Cracked head...blown head gasket...WORN RINGS...bent valves...burned
valves...valves not seating..spark plugs loose in plug socket...
Take a can of straight 30W oil...or 20-50..or even 80 rear end lube...put
about 3 tablespoons in each cylinder, and try it again...do one at a time.
See if the numbers dont jump right on up. If they do, then you have located
part if not all your problem...take it down, put rings in it, and look hard
at your pistons while you have them out and you may find, you have some
serious skirt issues too.
I swear..this is screaming an overheat and the rings lost temper.
of course, it could also be that you DO have a fiber gear, its stripped, and
you have all the valves open....how about you take the valve cover off too,
since its easy to get off, and spin the mother over and see if your valve
train is working...
Other issue that comes to mind....soft cam. Cams worn slap ass out....or,
you lost oil pressure and your lifters have collapsed completely...its
You wont unless you pull the cover...
And there are no stupid questions if you dont know the answer.
I hate to argue this point with you, but I have rebuilt more of those 2.5s
than I care to remember, and a couple of them did indeed have fiber gears
like my Ford..
and the main reason I remeber this is that I had to buy a damn cam retainer
on both of them.
We did put metal gears back in them...but they damn sure had fiber from
One was in my ex-wifes Fiero....and I remember that blue thing like
yesterday, and the other was in a Buick that my grandmother owned since day
one, and my brother took out the mains. I pulled it to rebuild it and I went
ahead and put gears in it too...
My sincere thanks for all the responses. The signs seem to point to the timing
gears since the compression is uniformly low in all the cylinders, but I'd like
to be sure before digging into the front of the motor to get the front cover
off. I seem to recall a way to veryify this by removing the spark plugs and
valve cover and observing the valves in relation to TDC but can't recall the
Will definitly try to "persude" the cam gear off without removing the cam, if
possible. Hopefully the harmonic balancer is threaded, last time I pulled one
of these it wasn't and I had to whack it back on with a mallet.Not fun.
Actually, if they are fiber, it would not run. Fiber gears will not jump,
but they will shread.
I would lean much harder towards a burned set of rings. But..thats from my
experence with that motor.
Dont even try it. You WILL be at the dealer ordering the cam retainer. That
is a given.
Pull the cam. The gears have two holes in them for getting at the cam
retainer, and it takes little to get it done right.
The bottom balancer has the main bolt that hold it on, and three smaller
bolts that hold a pully on. It is also pressed on, and kept in place wiht a
keeper. The bottom gear will slide off and slide on, also kept in place by
Not to disagree with Joe but the 1980's FWD versions of that motor did have
fiber cam gears. I'm not sure of the RWD's though. The fiber gear tended to
knock very loadly before failing.
The manual says to pull the camshaft because the cam gear is pressed onto the
shaft. There was no real provisions for pulling or reinstalling the gear. At
the dealer we made lots of money on these because warranty time paid to pull
the engines in the FWD cars.We would remove the gear with some careful use of
the air chisel. Some would drill the front of the camshaft to fit an installer.
Others would carfully remove the burrs and gently tap the gear back on the
cam.The later method would sometimes remove the freeze plug behind the cam.
you might want to take the opportunity and dump the Iron duke, even if you stay
small a 3800 v6 is a much better motor.....especially if you turbo it ala the
All aboard the Yankee express, next stop October.....
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