I did a compression test, ALL of them read 150PSI.

My haynes manual says Psi should be 100-150.

So my engine must be running pretty strong then right?

What compresion do you guys got?

 

155 here, on all but one that spiked 170 - rearmost passanger cylinder.

 

I got 120's on my 2.8l in my s10. Maybe thats where my problem is. Please others post to help me decide!!!!!!!!

:hail: :hail: :hail: :hail: :hail:

 

You've got excessive carbon build-up on piston and head. This causes the raise in compression.

 

Quite probable. As for the 120 psi, if they are all around there, I wouldn't worry too much - maybe squirt some oil in, then redo one of them - if it comes out noticeably higher, its worn rings.

As for the carbon buildup, I'm sure that's what it is. No biggie though, as long as they're all good, I'm good to go!

 

My 211,500 mile S-10 Blazer mill have only 50 pounds per cylinder.
It ran.
YOu got plenty to go!
New chain, rebuild distributor, max fuel output, good to go for LONG TIME!
Don't open engine for hopping it up,
Drive it into the ground. Rebuild body before the engine dies, then add the "new mill"
It'll be a way cheaper project that way.

 

"You've got excessive carbon build-up on piston and head. This causes the raise in compression."


All six cyls on mine are either at 160 or 170 and have been for a couple of years (though possibly worse now). Will it do any harm leaving it like that, or should it be a priority to fix?

 

oops pressed post twice

 

You could spray some water through the TB to decarbonize the piston top/combustion chamber, but I wouldn't make it too much of a priority, unless you notice excessive pinging.

Last time I did a check, which was a while ago, 5 out of 6 cylinders were in the 140-160 psi range. THe #1 cylinder was the dog at ~120 psi, probably caused by that spark plug that blew apart from when my timing was way overadvanced.

 

145 and runs strong, although weak in the rpm level.

 

Weak springs
or exhaust flow choking it or bad air inlet design.
That's reasonable-good compression.