Thread: question on compression cranking readings

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Question is on a 454 bbc stock bore 4.250, stock stroke ,118cc cumbustion chamber aluminum heads,block zero decked, .040 quench, stock GM LS6 forged .100 domed pistons.cam is a bullet racing mech solid lfter dur. @ .050 is 251/259 seperation 110. grind # CHB 277/289-10F. degree intake lobe to 104 icl gross valve lift .620. cam indexed straight up.

compression test readings 125-130 on all cylinders.
Are these readings about right for this setup.

I apreiciate you posts, thank you.
Jim

cylinders should be fairly even. Within about 10 %. You are well in that area. It is more about the seal of rings and valves than set up.

Thanks Desertdog.

Jimbo, questions regarding your testing method. Do you have ALL of the spark plugs removed, is the air cleaner/filter removed AND is the throttle being held at wide open when you are spinning the engine over?

Mike

Originally Posted by Mike52

Jimbo, questions regarding your testing method. Do you have ALL of the spark plugs removed, is the air cleaner/filter removed AND is the throttle being held at wide open when you are spinning the engine over?

Mike

Yes Mike that is how i did the test.I was told that me being at 4800ft that if i were at sea level the readings would more like 150 psi.
Thanks