just wondering does compression ratio effect results on a compression test, i had never heard about compression ratios before i got my cosworth, also what figures do you usually see on a bt yb, tested mine today and got 150 across all 4 cylinders.

 

Yes CR does affect compression pressure, 150 on all 4 is ok.
tabetha

 

Your allowed a tolerance of 10% over the piston's..... Had mine tested few weeks ago as was burning oil, 165% across 1,3 and 4, 45% on number 2.....