It was stated that Emon strongly recommends the 3 mm apex seals for a/c >applications.  Based on that, and the desire to not have my motor self-destruct >while aloft,  I decided that was the way to go and I signed up for a set of 3mm >seals/springs for my 20b.  I realize that I will need to have my apex slots ground >to accept the larger seals.  My question is this, is this really the best way to >go, or am I just solving one problem just to create another (higher weight & >wear), or are the 3mm seals recommended due to their higher profit-margin?  Also, >although grinding is the preferred method, would it be acceptable to have them >machined instead?  Finally, do you know of anyone stateside that can grind the grooves >for us?
Thanks,
Mark

I definitely think the 3 mm are the way to go. Since we run the engine at only
6000 RPM the wear should be good for at least 1000 hours. I saw Tracy's 2 mm seals
after he removed them from his engine at about 800 hours and the wear along the
sides of the seals was noticeably but not excessive. In any event if I can't talk Eamon into doing it on all 3 mm seals I will make a little drilling jig and drill mine in the drill press one hole at a time :-)

I have not gotten around to looking for an outfit that can grind the seal
slots. Should not be too hard to find however. You might even find someone >on the
internet.

Paul Lamar

Mark Steitle wrote:

What is the proper seal/slot clearance?

0.002 to 0.0039 inches. Maximum allowable is 0.0059 inches.
1994 Workshop Manual.

Paul Lamar
 
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