Quote:
Originally Posted by 40 Deluxe
Plus, cranking speed varies, ring seal may not be very good, valve timing varies (affected by lash), ambient temperature and coolant temperature vary, etc., so the compression gauge method is a waste of time!
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And let's add - overbore increases cylinder displacement relative to combustion chamber volume.
All in all, a lot of variables. That many degrees of freedom makes the engineer in me cringe. Having said all that, it's an attractively simple formula. And it's at least qualitatively correct - compression ratio and cylinder pressure do co-vary.
I think you, Y-B and I all violently agree.
JayJay