Packard Forum Index » V-8 (1955-56)

What are we striving for in the way of readings for a compression test?

In reality, what's good and what's barely acceptable?

I'm assuming widely differing numbers are not a plus.....

Where does this data lurk? I can't find it in the manual....

Here's what the 55-6 manual has to say. Engine section, page 7

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When completing a compression test, the goal is consistency more than specific numbers, provided you're above a minimum threshold. Ideally you want each cylinder to be within 10% of the average of the others, if not virtually the same across all cylinders. As a rule of thumb, any difference of more than 10 p.s.i. needs to be investigated with a follow-up wet compression test at a minimum so you can tell whether it's rings or valves. At the absolute minimum, I'd like to see above 130 psi in the V8's, and above 110 psi on the straight 8's.

Thank you.

Skimmed the manual and just missed that section.

Kindly keep fingers crossed....