Hey guys, I just installed a built motor in my car a few weeks ago. It has 750 miles on it as of right now. I used JE pistons 8:6:1 I believe and I gapped the top ring to .022. I did a compression test on the car today and got 140-145 in all cylinders. This seems to be a bit on the low side.
With all the cylinders being about the same and all low it makes me think that there isin't a problem with the rings sealing. I did have some water in the oil on the first oil change but the second one didn't seem to have much in it at all so the head gasket seems to be sealing fine now.
The EGTs have been high at idle ever since the rebuild so Im thinking maybe the exhaust cam is a tooth off. The car runs great and idle fine. Would the exhaust cam being a tooth off cause high EGTs at idle and lower compression then normal?
#108990, "RE: New motor - Compression issue" In response to Reply # 0
did you do the test at operating temp? if not make sure the engine is warmed to normal operating temp first. Did you have the throttle body completely open? also try the wet test, if the initial numbers still seem a little low then put a capful of oil in each cylinder before doing the test. If the numbers suddenly jump up significantly your rings are the issue, if not look back at the haedgasket not sealing.
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#108992, "RE: New motor - Compression issue" In response to Reply # 0
Originally posted by SilvrEclips Would the exhaust cam being a tooth off cause high EGTs at idle and lower compression then normal?
Yes.
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#109002, "RE: New motor - Compression issue" In response to Reply # 2
I think I am going to retard a the exhaust cam gear about 5 degrees and retest the compression. If that turns out to be the problem I guess I will have to go and retime it soon.
Yes I did perform the test correctly. But I didn't do a wet test.
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