Compression test?

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Oct 4, 2011 | 10:43 PM

#21

djl

HDF Community Team

Joined: Jun 2006

Posts: 12,763

Likes: 2,597

From: san antonio

Quote:

Originally Posted by soft 02

I may not be an expert on twin cams but my gauge is a two year old snap-on set. I'll change out the scherader Valve in it. So ideal would be 170ish. Is their a chance 195 is correct or is it mathmaticly impossible. I'm not arguing with you. Just put a lot of trust in my tools.

I will run the numbers through my calculator and you can check yourself with the BigBoyz calculator. I have done enough to know that a 96" motor with stock heads and a 41* intake close cam will generatea about 170-175 psi cranking compression. The variance will be in deck height and combustion chamber volume, i.e., differences in manufacturing tolerances. You would need 80cc chambers and cams with an intake close of about 34* to kick out 190psi.

I ran the numbers through my calculator assuming 85.5cc chambers, 0.00 deck height, stock heads and stock head gasket; 172psi.

I understand what you are saying about your tools but the math just doesn't work.