timb

Does anyone know what the normal compression in our engines should be? I just did the compression test and the all had between 350 and 375 pounds. Am pulling the head now so wish me luck.

Stomp

Dont know what it should be, but I want to say all of mine were right around 500 and #2 was around 460 or so. I dont know what Cummins recomends.

Stomp

JD730

I don't remember what the Cummins book said, but the last time I did mine they were around 380 psi at cranking RPM.

timb

Well after spending all night reading through the search forums on a few sites, I've come to the conclusion that there must not be a normal compression. I have seen them as high as 525, and as low as 260. Mine probably would not be as high as most due to the 20 over head gasket. From what I have read, as long as the cylinders are within 20% of each other the cylinders are ok.

wannadiesel

Cranking speed has a lot to do with it.