Hey all,
Im going to be doing a general tune up this weekend, and while im in there I was going to run a compression test. But ive never done one and from what ive heard its simple, but I would like to know what the compression should be or whats a good compression?

Ive heard as long as all the cylinders are either equal or within 40PSI they should be fine, is this right?

 

I dont think 40psi is right.
You should have within 10% difference between all cylinders. When you do a compression test you will be looking at psi.
First, if you have a decent stock longblock it should be around 140-150 psi with 9.5:1 comp.(with good rings)
I just recently did a compression test on my car with a stock shortblock and trick flow heads and was seeing 150-160psi on cylinders 1 thru 4. I have issues with the other 4 cyl's.(lol,,30 and 65psi respectfully).

Rye

 

shouls be within 25 psi of each other ..stock motor prob about 125 to 145 max ..unless you got lots of carbon buildup it will be more ....the best way is a leak down test

 

Thank you guys for the feedback Ill let you guys know on the results and then we can go from there.