Have searched this site for concise numbers for a compression test on an F355 motor. Nothing has popped out. Car has just had a PPI prior to a sale. Buyer says numbers came back in the "150s" and that is too low. Leakdown test came out fine, though. So what should the compression numbers be? Any help appreciated. Tom Elerding
There are no specs that I am aware of but the generally accepted # is about 210. Compression gauges vary a lot, so do testing methods and on a less than perfect motor test temp will make a difference too. With my equipment and the way I do it 150's would be bad. I also look for 0-5% leak down but up to 10% is OK. All those variables are a good reason to have a PPI done by someone with a great deal of 355 experience and is a disinterested party. They will know all that and that way they can render it all down into a simple yes or no to you.
Thanks for the information. Interestingly enough, the same dealer that did the belt and valve guide service is the one doing the PPI. They didn't tell me I had a problem. Their work is still within the 12 month warranty period, and they would probably like it if the buyer bought the car and took it out of state! I need to get this resolved with the dealer!
