Fred:
The O rings that you got are not valve stem seals per se. They are
designed to fit on top of the spring retainer just before the cotters go in.
They are there to prevent the oil that pools on top of the valve retainer
from trickling down the stem. They are actually a valve spring retainer
seal! When installed correctly they end up scrunched into the valve spring
retainer sealing it to the valve.
There is a real valve stem seal, known as the umbrella seal. It
fits on top of the valve guide and has a spring seal to the top. I have
never seen these in an original passenger car engine, but they do come in
factory head sets for the Sherpa truck.
Hope this is helpful. Many suppliers stock the umbrella seals, but
if the guides are clearanced correctly they are not necessary. You would
probably only want them on the intake valves anyways.
Hope this helps
Kelvin.
-----Original Message-----
From: Fred Pixley [mailto:fpixley@kingston.net]
Sent: Tuesday, March 14, 2000 5:04 PM
To: mgs-digest list; spridgets-digest@autox.team.net
Subject: Valve Seal O-Rings
I've just rebuilt a cylinder head on my Mini. It's a 998 and had no obvious
seals installed previously. I realize they are not required on the exhaust
valves, but the gasket kits include 8 o-ring seals. I installed them under
the retainers and they position themselves about half-way between the top of
the guide and the retainer.
I can't see how this will prevent much oil entering the guides although it
might help somewhat. Have I installed them in the correct location?
Fred Pixley
Napanee, Ontario, Canada
fpixley@kingston.net
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