[peterpeter]

Just want to know compression for new and worn conditions and what would be totally useless to give low power.

[JB]

Over 100psi and ranging less than 15% is a fair general rule, Peter.The important factor is the range. If one or two are way low you have trouble.Good luck.

[dingbat]

Depending on the motor you should be somewhere @ 125 PSI. Anything more than a 5-10% variance and you've got troubles brewing.