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,

    My leak-down tester is 20yrs old, used it regularly on the B55
    Baron IO470-L's I owned. I have also used it on some if the
    Diesel engines I operate.
    Best Regards
    Rolland (Philippines)
    KitFoxes RP-S135/S2804
    12a Single Rotor

    What numbers are you seeing on the one rotor Rolland?

    Paul Lamar ...No rotor no motor.


    Paul,
    12a Single Rotor Compression by Leak-down 26 to 42/80 psi,
    the readings do not repeat, tried a squirt of ATF,
    got higher reading 55/80 for about a minute
    but sags down to the lower numbers.
    Best Regards
    Rollans (Philippines)


Thanks Rolland. Exactly the kind of data we are looking for.

Not good. 55 is only 70%.

I hope it stays higher when it is running.
Are all three rotor faces about the same?

Lets consider the 80 psi a standard.

Do you know what the orifice diameter is or was or the brand
of compression tester you are using?

If this is typical I can see why Mazda is putting so much effort
into the design and manufacturing of apex seals.

Mazda has come a long way since the 12A with apex seals.

Paul Lamar ...No rotor no motor.

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