I  finally found the specs on that National oil seal.
Here it is. A friend  loaned me a Timken catalog on CD.
IMHO it is marginal for our  applications.
The shaft is rotating up to 7500 RPM and the heat can
be  well above 200 F which is the limit for nitrile.

I highly recommend a  spring loaded graphite Teflon seal in this
application. Plus of course a  truly concentric and parallel installation.
I am looking for one that will  be a perfect replacement. No need for a
bushing.

Paul Lamar ...No rotor  no motor.

This is as close as I can find in the National brand.
It  will require boring out the adapter plate or the new bell housing.

--
Paul Lamar ...No rotor no motor.

Paul,
I am sure that the spacers can be made close enough to the same  length
easily enough. The bellhousing will be more consistant of course. The
concentricity or lack of it is the real problem. This is also addressed
with the  bell
housing. It would be interesting to have the guys that have pulled
a  leaking
seal to check if there is more wear on one spot. You would have to use a
magnifier but I'll bet you could find it.
Bill Jepson

Bill,
My seal leaked because it partially slipped out of its bore which allowed
oil to seep around the outer perimeter of the seal.  Also, the seal moved
enough to allow the wear surface to touch the shaft splines,
possibly causing damage to the sealing surface.  When I pushed it back down
into the bore, it still leaked, but I couldn't tell if it was from around
the outer perimeter or past the sealing surface.  Since I was getting weary
of removing/replacing the psru/prop, I decided to replace the seal with a
new one.  The new one was a proper fit and isn't leaking (yet).  I'll keep a
close eye on it.  I plan to go with the Cadillac (graphite) seal for the
bellhousing.

Mark St.


The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.