today im going to go borrow a tool to check the compression of my engine. does anyone know what the figures for a healthy 2.8 would be?

 

I had between 140-160 PSI on 5 cylinders, and 120 or so on cylinder #1.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

When I did my 3.4 I was getting close to 200 on each cylinder.
When I just adjusted the valves on my 211,500 mile 2.8 1989 S-10 Blazer, I was getting close to 100 and less.
BUT, My Blazer has started. No oil smoke, tho.
Just lousy oil pressure from a bad worn out oil pump. Due to it sitting in chocolate milk for two months while I did the head gasket job & cylinder head swap.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

tom p was your readings taken when the engine was hot or cold?

 

i'm kinda confused on how to do the compression check. I've got a new 2.8L block, and when it was installed i was told it should run about 180psi. I almost bought a compression tester, but then didn't know how to use it so i held off. What is the process with the testor? thanks.

 

you can do it hot or cold. if u do it hot u end up burning your hands and arm on the manifolds valve covers ect,,,,
the way i do it is cold. remove all spark plugs get some wd-40 or tap fluid or some oil use a little on the compression tool threads. insert the compression tester in one spark plug hole make sure its tight.if you have a carbarator or choke it has to be wide open. also on carberators you have to push the gas pedal to the floor when you cranking over the engine.dont crank more than u have to cause when the plugs are out the coil is sending double the voltage and that can cause youre coil to over heat. take 5 min in between cilinders. wright down the #s that u get so next time youll know if youve lost any compression between tune ups.
if the compression is low take a teaspoon of oil put it in that cilinder crank the engine once or twice to clear the remaining oil in the engine insert the tester and take your reading agian
if the compression goes up your rings are bad if it doesnt go up your valves could be bad or are not adjusted right. if there is a 10 psi difference between cilinders it might have to be fixed soon watch for smoke out of the exhaust.