Re: Any thoughts on the cranking compression in the Shop Manual?

Posted by PackardV8 On 2018/2/20 17:21:56

There is a calculation for compression reading.

A QUIK rule of thumb is CR x ATM.

1 ATM = APPROXIMATELY 15 psi (that is atmosphereic pressure) times the CR.

So the 7.5 x 15 = 112 psi compression..

8.5 x 15 = 127 psi compression.

NOTE that there is somekind of a fudge factor or other relatively minor factor added to the equation for CR > 12:1.
Maybe google it if u really need extremely accurate calculation.