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danlrhubarb
04-06-2023, 04:19 PM
Have a F4-134 in my Willys MB, not an L. The compression in 1-135#, 2-135#, 3-95#, 4-115#. There was a little foam in the Rocker Cover but the oil was not foamy. I think whatever happened, just happened. I am hoping it's the head gasket. What would you all do next?

bmorgil
04-06-2023, 05:30 PM
A couple of things danl, first what procedure did you use to measure the cylinder pressure? It is important to follow this procedure.

https://willysjeepforum.kaiserwillys.com/showthread.php?3112-How-to-Correctly-Check-Compression

Following the above procedure, you can first check out the rings. Next depending on where it seems to be loosing pressure, you can check the head gasket with a cooling system pressure checker and the valves by the process of elimination.

Let me know what you come up with following the above compression testing procedure, and it should be easier to pin it down. What do the spark plug electrodes look like from each cylinder especially 3 and 4? Are the plug threads wet with dirty oil?