In a message dated 04/15/2005 1:44:52 AM Central Daylight Time,
lendich@optusnet.com.au writes:

<< On Thu, 14 Apr 2005 16:26:19 -0500, Russell Duffy wrote:
 > > Apex Location Base Top
 > >
 > >
 > > Seal1 1.99mm 2.16 - 2.26mm Seal2
 > > 1.98mm 2.22 - 2.25mm Seal3
 > > 1.98mm 2.18 - 2.20mm Clearly the slot is larger at
 > > the top - is this due to design or is this due to wear? Lynn??? >>


The slot is perfectly straight. No taper at all. If you stand a new or near
new apex seal on end in the slot, the exposed end should not move more than
(about) 3/16" total. New slot and new seal gives nearly no movement. The 3/16"
would be end of life span.

For aircraft use, new or nearly new is the way to go.

You can take engines apart that have been running fine, and the apex seals
are just about to fall out of the slots they are so short. The slots can wear
into obvious "V" shapes, and the engine is still running fine. My wife's RX-3
did that. I was just sitting at a stop sign one day and whack!!  A seal came out
of what was left of a big "V" slot and the rotor crushed it against the
housing. There was no chrome left on the rotor housings. Big grooves in the irons.
The only piece I could use was the crank.
The whole thing was scrap.  

The rotors are made of cast steel. You can weld on them. I have TIGed holes
shut and built up gouges and smoothed them off. Again not for aircraft but for
a dune buggy or any non critical application, I see no reason for scrapping a
piece I can fix quickly.

I grew up during W.W.II and you were literally not allowed to throw anything
away. So I don't (until recently).

Lynn E. Hanover