compression ration vs psi
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Joined: May 2015
Posts: 344
From: Southern Virginia
compression ration vs psi
Question for you physics majors. I recently checked the compression on the 68 455 engine I am installing. The readings for a cold block with all plugs removed and no carb on the intake were between 190 and 200 psi for each cylinder. How does PSI relate to CR? The engine has C heads with new valves and was bored .030, previous owner was not sure what pistons or head gaskets were used. Thanks to all
Connoisseur d'Junque
Joined: Sep 2010
Posts: 21,183
From: The Hudson Valley
It doesn't.
It relates to CR and cam profile and timing.
Without knowing the details of the cam, it is impossible to suggest an exact cranking compression number.
That being said, your numbers are normal for a '68 engine, and probably represent a high compression engine.
- Eric
It relates to CR and cam profile and timing.
Without knowing the details of the cam, it is impossible to suggest an exact cranking compression number.
That being said, your numbers are normal for a '68 engine, and probably represent a high compression engine.
- Eric
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