I just bought a 68 Cougar with a 302. I ran a compression test and 1 Cylinder was 168 psi and the other 7 Cylinders between 198 - 202 psi., verified it multiple times with the same readings. Ran a scope down the plug holes to check the piston for carbon build up and nothing out of the ordinary was found. I have done this test many times and this was a first. I have seen low compression but never high compression like this. The 168 psi is about right, I just don’t understand why the other 7 are so high. Any help would great, I just don’t have a answer for this problem.
Was the engine warm or cold? The compression seems high. More information on the engine might help. Does the engine run? If so how does it run? Is there oil in the cylinders?
Steven
Compression was done at running temperature. J Code 302 230 HP. Engine Starts right up, smooth idle, no smoke. When I purchased it, I picked it up in Los Angeles and drove it back to San Diego with no problems. Since I have done the compression, I have been a little hesitant to drive it until I can find out what is causing it to be that high. Thanks for the response
It is also a Standard non XR7.
I’d be concerned with the 1 cylinder being lower than the other 7. Overall high cranking compression is due to early intake valve closing time. Someone may have advanced the cam.
Well, all I was told that it had engine work done and that’s all I know. It’s frustrating not knowing the story of the engine work that was done. I will never know other than speculate it.