Low Compression on Cylinder 4

Posted by Tom On 2019/11/25 10:48:33

I just finished a compression test on my 1946 Clipper.

The compression range was 70-85 PSI across all the cylinders except cylinder 4 was 45. When I put oil in the cylinders, compression went up to 85-90 across the cylinders but Cylinder 4 stayed at 45. My understanding is this points to a valve issue or head gasket.

Is there anything I can try with the valves specific to this cylinder before ripping everything apart for a rebuild?