X-Mozilla-Keys:                                                                                 

 Paul:   nikasil coatings are put on by aircraft cylinder remanufacturers .
It isn't this process I am concerned about It ti the warpage , sealing and
cooling of the housings.The design of these pieces becomes more critical than
the wear coatings!  JIM DANA

Jim, here is an idea for you. Since the tension bolt problem is
causing the rotor housings to shring when the engine is overheated
and the problem would get worse with aluminum end housings I suggest
a little low cost R&D.

Get a Mazda tension bolt. Get a piece of thick wall aluminum tubing
with approxmately the same ID as the Mazda tension bolt.
Clamp the tubing with the bolt and a nut.

Heat it in a kitchen oven to 200 degrees for an hour or so to 
allow everything to stabilize.

Remove from the oven, let cool  and measure the length of the aluminum
tube. 

Increment the oven temp by 10 degrees.

Repeat the test until you discover the aluminum tube has 
been permanently compressed. Note the temperature at which
this happened.

Simulate a 13B rotary engine by using alternate cast iron and
aluminum spacers.

Repeat the above test.

Now try Belleville springs under the head of the Mazda tension
bolt.

Repeat the test.

Report the results on here.

If you can solve this problem proceed with the design of
the aluminum end housings.

Paul Lamar
 
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