tom kimsey wrote:

please see the attached photo of the teflon encapslated silocone o-ring damage to my engine that i was discusing with you at the gathering at Tracy's house. I asked you in a later e-mail if you remembered the part number of the ring that you sent to me( outer coolent) and you told me that you could not remember or had lost that information. I believe that the TES o-rings are a worth while improvement to this engine and ended up using the TES o-rings at the inner position and using the stock Mazda rings at the outer after i discussed this with Bruce Turrentine. I have some more jpgs of the damage to my front and rear side housings if you would like to see them. Tom kimsey

That is real strange looking Tom. Did the silicone part extrude itself out
of the teflon cover and into the crack? I can't for the life of me understand
how this happened. Perhaps there was a core shift in this casting that left
a very thin amount of metal under the O-ring groove. Can you take another
close up picture with the O-ring removed and the two cast iron parts
removed so we can see the floor of the O-ring groove?

Paul Lamar

How can they stretch that much?  That looks like about an inch worth.
How was the engine running when this happened?  On a test stand or
in a car or plane?  How many hours?  I would like to see more photos.
Looks like it had to be some kind of flaw in the housing.  What is that
circular area in the "floor" of the groove above the break?

I've got 55 hours on my new engine with these rings, everything is
perfect.  I think Ed Anderson has them too.
--
Perry Mick
Duckt N7XR
http://www.ductedfan.com

The installation trick for the new guys is to get them slightly undersize
and stretch them over a plywood form for a few days so they lie in the slot
perfectly when assembly the engine. They tend to take a set once they
sit around in a given position. This was discovered after Don installed 
his O-rings and his o-rings might have been slightly oversize.

Paul Lamar

 
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