Thread: Changing compression ona built motor

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Tech,,, measured the compression across all cylinders and it ranges from 212 to 218.
now what lol

Originally Posted by HotRodN

Tech,,, measured the compression across all cylinders and it ranges from 212 to 218.
now what lol

Holy crap!
Can you hear the motor detonating? What fuel did the original owner use in the motor? What fuel have you used in the motor?
It is possible that it is not detonating if the builder engineered in a very tight squish when he built it. (0.035").
If the motor is detonating on premium pump gas, the cheapest way to lower the static compression ratio is by changing pistons. Are you up for that?
A 12cc dished piston would put the static compression ratio at about 9.5:1 SCR, perfect for iron heads on pump gas, as long as you use a tight squish.

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