frank69m

I'm getting my first compression check next week from a local rotary shop. Can someone tell me what is involved with doing a compression check? Looking for boost leaks? Should I do it once in a while even though I don't seem to have any problems?

Nathan Kwok

The compression check basically indicates how well the engine seals internally, so if you have bad seals (usually apex seals), it will lower the compression. It won't reveal boost leaks or any problems outside the core of the engine. Once you establish the compression is good, unless something noticeable happens to indicate there's a sealing problem, there's no real need to check again. The minimum acceptable is 6.0kg/cm^2 on all 6 faces, with a maximum difference of 0.5kg/cm^2 between any two faces, this is at 250rpm and at sea level. Most people test around 7. Hope that helps.

dclin

Yep, like this. High 7s, consistent all the way across. This is 7000 miles on a reman, premix religiously, break in oil change at 1000 miles (wish I had done it sooner) oil changes very 1500-2000 miles afterwards.



Previous engine had low 6s both rotors, and would stall every now and then with a/c on.