[xj-s] Valve Stem Seals

["Michel Carpentier" <carpenti@math.jussieu.fr>]

Kirbert wrote:

>Yo!  Does anyone offer these for the XJ-S?

Perfect Circle does (although unwittingly since I doubt they ever
considered Jaguar engines as a possible application for their product). Our
valve guide diameter is 0.502 to 0.501 in, that's essentially 1/2" or
sixteen (16) thirty second of an inch. Valve stem diameter is 0.3092 to
0.3093 in, and that's within 3 thou of 5/16" or ten (10) thirty second of
an inch.These dimensions are a bit unusual but luckily match those of the
first generation Chrysler Hemi engines. Call Perfect Circle (they are a
DANA subsidiary) and they will tell you:"yes, we manufacture such teflon
seals, part number D1610, available at any NAPA auto store". 
There is a catch: if you go to NAPA and ask for this reference, they look
it up in their computer and tell you it does not exist (never mind telling
them what kind of car it is for...). I e-mailed Perfect Circle a couple of
times about this but never got an answer. 
The last time I was in the US, I tried numerous auto stores and machine
shops in search for these elusive seals (I am rebuilding the XK engine on
my 420G, same dimensions). I finally found a place in Los Angeles that
would order them for me. This took about three months.
The seals actually came from a company called Silver Seals Products/Whip-L
Products, Trenton, Michigan, 1-800-521-2936; their reference is DT1610 but
the seals carry the Perfect Circle logo. You might want to get directly in
touch with these people .



>And why would better valve seals affect crankcase pressure?

Our engines came from the factory with 24 valves but only 12 valve stem
seals. Jaguar probably realized that the British rubber intake rendition
would soon fry on the exhaust side. 
The question should therefore be rephrased:" why would any (effective)
exhaust valve seal affect crankcase pressure?"
When the exhaust valves open, gases gush out of the combustion chamber with
tremendous pressure. Even though the valve itself acts as some sort of an
umbrella, there is still a significant pressure differential between both
sides of the exhaust guide. Any clearance between valve and guide will let
exhaust gases into the crankcase area. Jaguar old trade secret to keep
engines leak oil!

 Cheers

Michel Carpentier

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Follow-Ups:

• Re: [xj-s] Valve Stem Seals
• From: Mike Morrin <mikem@southern.co.nz>
• Re: [xj-s] Valve Stem Seals
• From: "Tony Bryant" <Tony.Bryant@psc.fp.co.nz>

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