when doing compression readings w/oil. how much psi of a jump will consider bad rings?

 

Usually you want the no-oil reading to be no less than 80% of the oil reading. This percentage increases somewhat with valve leakage.

 

the way i see it if your below what your suppose to get w/out oil and with oil it is at normal cylinder pressure then you know your rings are bad, not necessarily knowing the percentage just judgment of knowing. If that's any help