heinrich

First, this is not on my 928. But it is a 302V8. All cyls test within tolerance except one at 21% over the lowest. All spark plugs are beautiful. So, is this carbon buildup? Since the plugs all look the same with no oil and no coolant, and no coolant is consumed, and oil remains perfectly clean, I doubt I've got any liquid in the cylinder. Any thoughts would be appreciated.

Rich9928p

Did you re-do the compression test to see if the high cylinder reading wase consistent?

Did you do a wet-dry test to see if the compression of the other 7 cylinders increased?

Have you done a leak-down test?

You might have one strong cylinder and seven weaker cylinders.

heinrich

Rich since the high was 10.8, I assumed that it was above spec where the others were ~9.2avg, which I believe is more spec. I can perform the other tests, the high compression on one cyl just stood out so much that I assumed it was over the top. I'm told to expect between 130 - 160psi and I've got 132avg and 158 on one.

heinrich

btw yes i tested twice.