cranking compression

[tsm3089]

what kind of compresion # are you seeing. I have 247 ci about 9.4 to 1 compression 224 224 110 lsa cam did a check and have 180 at all 6 Dont think i ever saw it this high but motor just went together and have a brand new battery.

 

[jasjamz]

I'm not a guru but I foresee you being asked... was this a warm engine any of the other plugs in while cranking, throttle open or closed. Last one I did was 90 on the first hit and 120 Max on all 6. No plugs, battery charger connected, cold engine like 90*, throttle closed. It was a .040 over maybe 8:1 or lower 212/212 hydraulic roller. Glad you got it back together!

 

[bison]

what kind of compresion # are you seeing. I have 247 ci about 9.4 to 1 compression 224 224 110 lsa cam did a check and have 180 at all 6 Dont think i ever saw it this high but motor just went together and have a brand new battery.

I see 180psi also on my 233ci 9.3:1 engine with a 218/224 110LS adv 2*. It doenst tell you much though.

 

[NCTURBOS]

The intake valve closing will play the largest into this... Your static compression is approx. 9.4:1, but the corrected compression is what you're seeing when running the CCP test. The later the intake valve closes the lower your CCP will be, and vice versa. If you move the intake closing specs. around on the same camshaft your CCP will change. This will change how the motor tolerates detonation also. And can vary the spool time of the turbo, rpm "rev" time, rpm powerband, etc...


K.