Anderson Ed wrote:

Paul wrote:

Anderson Ed wrote:

Paul wrote:

Anderson Ed wrote:

Well, Gang,
  I went back out to the hanger <snip>

Are your housings grooved inside the water jacket Ed?. If not now would
be a good time to do it or have it done.

I suspect that this grooving will also reduce or eliminate the shrinkage
in
case the engine overheats again. It does this be relieving the thermal
stresses on that part of the rotor housing. Not to mention of course
it improves the heat transfer from rotor housing to the coolant.

As it turns out the rotor housings were grooved in the coolant galleys
near the spark plugs.

For future reference did this area of the housing shrink?
The resistance to shrinking will also be a function of how deep
the grooves are. The depth of course is limited by the steel
trochoid liner.

Actually, that area did not show as much shrinkage as the rest of the
housing. Perhaps because it was kept cooler??

That is one factor. Since the shrinkage is caused by the aluminum 
expanding
in column mode against the steel bolts by cutting the column into small
segements it gives the aluminum room to expand. It is best to groove the
hot
part of the  housing almost all the way to the exhaust port. Cut the
grooves
deeep enough to see sparks from the cutter. You then know you are down
to the
steel "teeth" on the trochoid liner.

Also check with ARP bolts to see if they will make a set of necked
down high strength tension bolts for you with a lower spring constant.
This too will reduce the tendency of the housing to shrink when
over heated.

I notice that Hayes offers a "necked" down tension bolt -
is that the same thing you are referring to??

Yes Ed I hope so. Early rotary engines used them but ARP claims
thiers is stronger so they could in theory be necked down with
a lower diameter lowering the tensile spring rate and making the engine
better able to withstand overheating. Please ask Hayes what the
necked down diameter is and then aks ARP the same question.

I will do that

Ed

 
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