Paul;

Don't miss my point.  The problem with the aluminum end and center

housings

was not in the strength of the through bolts, it was in the weakness of

the

housings themselves.   They crush with successive exposure to clamping
torque.   Aluminum housings made by anyone, including Mazda, will

exhibit

the same weakness.  Only the external flanging you mentioned would get
around that, and now we are talking in theoretical terms about a whole

new

program.

Our point was that "creep distortion" would be acceptable in a race car
engine destined for one race or maybe one season.  But for a 4000 hour
aircraft engine --- no way.  Hence the entire notion of an all aluminum
engine was abandoned.

Alan Tolle

Sorry Allan I don't buy it. Lots of high power all aluminum heavy duty

piston

engines out there with stud bolted heads and cylinders. I have no idea

what

alloy Everett made the end housings out of or the heat treat or the wall

thickness.

Racing Beat has well over 300 dyno hours on a 1200  HP three rotor
with aluminum center and rear end housings. That is over 400 HP per rotor
and would be 800 HP in the case of a two rotor of course.

I still say there is a differential thermal expansion problem that Everett

did

not address. Racing Beat has not addressed it either but they are very

careful

about warm up and not overheating the engine. The aluminum rotor housings
that "creep" are from engines that have been overheated. A common problem
in the old days. If you run the engine hard before the steel bolts are
as warm as they are going to get the problem is worse.

Paul Lamar

Paul,
It's good to get the feed back from Alan, but I agree that the housings
aren't the only cause, however the cast iron housings could be less of a
problem with expansion.

The bottom line as you say is to not overheat the engine and is why Mazda's
need warming -up.

Have you considered Titanium bolts, I believe they have a similar
co-efficient to aluminium
George ( down under)

That is a real good idea.

Paul Lamar
 
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