What is the stock compression ratio of the 3rd Gen. Cummins ISB 5.9L?
Is it the same for all 24V Cummins engines? How about static compression in each hole?

 

Stock CR on mine is 17.something. I think yours is a few points lower.

Nick

 

17.2 : 1 Compression ratio ISBe

 

Taking the 17.2:1 ratio if you figure up how much psi you should have on the compression stroke what would it be? P1V1=P2V2, anybody know what the volume is when the piston is all the way up, I think you would have to account for volume in the head as well. I have seen #'s ranging from 300-400 psi on compression testing. What's everyone's take on the normal number to get assuming rings, head etc. are all working perfect. Jay

 

Thanks to all who responded. I finally found it in the book........17.2:1 is correct. The new 6.7L is 17.3:1.