[Vwdiesel] Leaky cam seal

[Lee Hillsgrove]

  Not a labyrinth, but a helix. Since the cam turns one way only, the molded
helix lines act as a "pump" to help push the excess oil away from the
sealing surface. They also serve to keep a thin layer of oil near the
sealing lip for lubrication. The area between the dust lip and main sealing
lip may or may not be prelubricated with a layer of grease from the factory,
but any weepage past the main lip will tend to get caught in this void and
help seal and lubricate if not. I have some very expensive grease I saved
out of "empty" grease kegs that's the color of Prussian Blue and which is
loaded with Teflon - very slick stuff. It was used to fill the area between
the sealing lip and dust lip on a particular strut seal we produced at my
previous employer. If you put some between your fingers and rub it around,
then wipe it off, it's still slippery.

 An interesting seal is the valve stem seal - it's made to leak a controlled
amount to lubricate the valve stem, but not so much as to burn an excessive
amount of oil. Many of them are made with continuous "threads" molded into
the sealing surface for this very reason. The depth, pitch, and number of
passages can all be altered to fine-tune the amount of oil allowed to pass.
One of the engineers at this company I used to work for held a few patents
on the details of this feature. We used to mold millions of the things. What
amazed me and helped to illustrate just how big the auto industry really is
was a shock absorber seal we used to make. It went to either Gabriel or
Monroe, I can't remember. We used to sell almost TWO MILLION of them every
MONTH. Where do they all go? I know some were slated for the OEM and some
were aftermarket, but even so. Wow.

Lee
Oo-v-oO
PP-ASEL
KB1GNI



----- Original Message ----- 
From: "H.Hagar" <h_hagar at prcn.org>
To: <vwdiesel at vwfans.com>
Sent: Sunday, August 29, 2004 11:17 AM
Subject: [Vwdiesel] Leaky cam seal


Cam seals ?  all the seals here are red silicone very soft rubber so they
seal well.
Even if reused.  Use a little silicone seal from a tube if in doubt.  The
way I remember
VW uses a labyrinth there.      By the way newbies   do not do like I
did ---
start the engine with no VC. -------oil got on to timing belt --and was
thrown all over the
place.  Paints a nice straight black line in driveway. and on your white
shirt.

Hagar.

PS:  Tide ?  whiter than white ?  bullshit.
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