Re: Engine & spark plug Condition info, FYI

Posted by Jack Vines On 2016/5/19 14:45:47

IIRC, your car is a '55 Patrician 352" with 8.5 compression ratio. The Shop Manual specifies a cranking compression of 120 lbs/sq in. minimum at 150 RPMs.

Assuming you performed the test as directed; throttle full open, all plugs removed, fully charged battery, yours is definitely lacking.

The next step would be a leak-down test of each cylinder on TDC. This is more exact than a cranking compression test and listening for where the air is leaking will indicate intake, exhaust or rings.

jack vines