300D Compression Test
 

Hi everyone,

I just purchased a rotted-out 1976 300D for next to nothing, as I need the engine for a 79 300D. The compression test was done cold and had values of 290-300-300-315-315. How good is this? I've read that some people do hot compression tests. Why is this? What should be the values for a cold and hot compression test?

Thanks.

Denis

I am unaware of the values for a cold test. The reason for the hot or rather warm test is that the metals naturally espand with the heat and this is actualy your true compresson when running I believe.
I could also be wrong but makes sense to me.
I think your numkbers are a little low but the 315s arewithin spec. I would be concened about the 290 cylinder but again since this was cold that may not be a bad number.