finally took some numbers this evening... engine cold, WOT, no fuel, all the plugs out...the gage max'd out at 140psi on all but 2 cylinders which were 137&135. Realistically, I think the cranking speed was starting to drop towards the end. What's a good PSI for a stock engine?
checked compression
- Thread starter 300kGN
- Start date
Welcome!
By registering with us, you'll be able to discuss, share and private message with other members of our community.
Not sure how Buick does it but I know on a few other GM's the compression is in specs as long as the lowest cylinder pressure is not more than 10-15% less(depending on make/engine) of the highest compression. So your numbers look pretty even. I did a compression test on mine when I had just bought it and they all renged from 145-165. Usually anything under 120 shows signs of wear and below 100 might start to cause a missfire. I wouldnt worry about, looks good to me......... as long as the engine hasnt been completely rebuilt that is 
my1stgn said:Not sure how Buick does it but I know on a few other GM's the compression is in specs as long as the lowest cylinder pressure is not more than 10-15% less(depending on make/engine) of the highest compression. So your numbers look pretty even. I did a compression test on mine when I had just bought it and they all renged from 145-165. Usually anything under 120 shows signs of wear and below 100 might start to cause a missfire. I wouldnt worry about, looks good to me......... as long as the engine hasnt been completely rebuilt that is
Right on the %'s The only new core parts, the timing set! Looking for more peak pressure examples, thanks.
