How many people on here have differential compression testers?
I am trying to get some baseline numbers on rotary engines.
http://www.skygeek.com/ats-2em.html

They cost about $84 from this source.

This is a rock solid way of finding out if your new after
market apex seals are junk. If they leak more than stock Mazda
seals you can be sure the people that made them do not know
what they are doing.

It is of course also a good way to gage the condition of your
engine.

When I get a chance I will do the engine in my RX8.

Paul Lamar ...No rotor no motor.


I have one of these testers.

Almost all A&P/IA's (which I am not) will have one too.

I think that's about the going price.

http://www.chiefaircraft.com/airsec/Aircraft/Tools/CompressionTester.html


Matt-

Thanks Matt. Anybody authorized to do an annual on a certified aircraft engine
must have one... I think. I bought mine about 15 years ago to check the
O-470.

-- 
Paul Lamar ...No rotor no motor.

Paul,

Yes you are right but aren't they calibrated for the specific type of
engine?

Doug

Everything is relative. They work on O-200 to R-980 so the cylinders
will be widely different. The engine manufactures  give you a standard for their
engine. That is why we need base line numbers for the rotary.
both new and old.

Matt can probably confirm that anything less than 73 psi
for the O-470 is a bad cylinder with a 80 psi supply pressure as I recall.
My shop manual for the O-470 is out in the hangar.
I'll have more info on this in the future.
http://www.sacskyranch.com/faqcontinental.htm

90% is acceptable and within wear limits. 80% is borderline, and 75%
is ready for over haul with 80 psi in.