9.5 atmospheres to 1.
1 atmosphere = ~14 psi.
9.5 X 14 = 133 psi.

Having said that, all cylinders should be within 10 psi of each other.

If the highest pressure is 120 psi all other cylinders should be no less than ~110 psi.

If all are within range, compression is usually AOK.

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PDQ

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"m Ransley" wrote in message ...
| OK but what compression rating equals what lb. a factory new 9.5-1
| equals how many pounds pressure with a compression tester. It has to be
| a simple formula.
|