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Dale,
Not being a rotary engine
mechanic, I only know that one of things that you were to check for after a case
of "overheating" was "shrinkage" of the aluminum rotor housing. I never
heard an explanation for why this supposedly happened but the thing you
were to check for was the width of the housing. There were minimum specs
which if below supposedly rendered the rotor housing "Bad". I do know that
when I took my first engine apart after overheating it to the point that the
inner coolant seals failed, I measured and found one of my housings right at the
limit - now it may well have been at that point before I ever ran the engine as
I did not measure it before hand.
The only thing I could ever think of that might
cause this (assuming it was caused by overheating) is that we have 17 of those
big bolts holding that pancake together which compress the rotor housing between
the iron housings. If it go hot enough supposedly that clamping pressure
could cause the aluminum to weaken sufficiently to partially collapse the
housings coolant chambers and reduce the width of the housing. But, that
was just my take on it.
Now with the later engines I have not heard about
this shrinkage problem - so whether it was an "old wives tale" or there was some
substance to it that has been overcome by better castings/alloy , I really do
not know.
Ed
Thanks Ed, I value your insights.
I know that seal
chatter was an early development problem with the wankel, but thought that
Mazda had pretty much made it a thing of the past with modern materials,
geometry, and springs. I did not realize that this was a temperature
dependent problem, that we still had to deal with.
Also, not quite sure
what you mean re: "shrinkage of the aluminum rotor housings"? It
can't shrink with heat. By this do you mean that, that having exceeded
some elasticity limit, the aluminum cannot return to it's original specs upon
shutdown once it has been overheated? Wouldn't it thus be
oversize? Please explain ... this sure sounds like an "engine
killer".
Thanks,
Dale Smith
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