>> One more question Joe.
     >> Was the EM2 or the Microtec controlling ignition?
     >>
     >> Paul
     >
     >
     > I have the MicroTech. That's what Atkins sells with his engine
     > package. It seems to be a reasonably complete and robust system.
     >
     > Here's a picture of the broken sparkplug.
     >
     > Joe Hull
     > Redmond/Seattle WA, Cozy-Mark-IV - 71hrs
     >
     > Thanks for the picture Joe.
     >
     > I think a slightly smaller gap might prevent the broken ceramic
     > from dropping below the ground electrodes.
     >
     >
     > Paul Lamar ...No rotor no motor.
     >
     > That is a different spark plug from the standard 2nd gen
     > BUR7EQ-L/BUR9EQ-T? Looks more like the spark plug used on the first
     > gens?
     > Perry Mick

    Thanks Perry.

    Jim Mederer and Dave Lemon, have you seen this failure before.
    The supposition is the ceramic insulator failure took out the
    apex seal. Is this a common problem in racing engines?
    --
    Paul Lamar ...No rotor no motor.

    Hi Paul,

    A broken plug insulator usually means the plug was too hot,
    detonation - or both.

    Jim Mederer

    Thanks Jim.

    I know it is not a common problem in street engines as there
    have been over a million Mazda rotary engines sold and if this
    were or is a common problem I am sure Mazda would not have sold a
    million engines. This plug was from a normally aspirated engine
    with 35 hours of high power running so detonation was unlikely.

    So keep checking your plugs guys when the engine is new
    to be sure they are not overheating and the plugs are of the right
    heat range.

    It is the duty of the engine builder to put heat range plugs in
    the engine that are consistent with its intended use. If the plugs
    prove to be too cold than adjustments can be made later.

    Jim, given this scenario what plug numbers would you recommend?

    -----------------------------------------------------

    Here is a plug color chart to check your plugs.

    ops that did not work. Try this one.

    --
    Paul Lamar ...No rotor no motor.


Hi Paul,

    By the way, you cannot read the "color" of rotary plugs and tell
anything definitive about mixture.  Because of the lack of a cooling
cycle, the plugs run so hot that, at best mixture (power), the plugs
come out "white".  You also cannot tune the engine with EGT or O2 - it
varies all over the map.  Only power matters.

Jim Mederer

Bad news :)

We are now working towards installing a torque meter
in the gear box so we can know the HP at all times.