I have searched and I know on piston engines that the numbers are higher when the engine is warmer. I just read on here though that the numbers are higher when it's cold. I just did one on my engine and I cranked it up only for three minutes then parked it in the garage. The numbers were 102 for the front and 105 for the rear. So is the cold theory true? If so I guess I will be in for a rebuild soon? Thanks

 

You should have 3 numbers for each rotor. I will guess that you also used a piston tester. A rotary compression tester is the only way to get exact numbers.

Assuming that the other faces are near the numbers that you posted, the engine compression in fine. No need for a "rebuild soon" based off that.

how to http://www.banzai-racing.com/compression_test.htm

 

yes, each rotors pulse was 60 on a piston tester holding the pressure release. That was front and back.

 

Follow the link:

Note: if you do not remove the Schrader (relief) valve, you can also hold the valve down during the test and watch the needle bounce for each rotor face. However, you will not see actual compression readings. Once you have confirmed three even bounces, you can repeat the test without depressing the relief valve to ascertain the compression reading.