<VV> Crank seals

[Rick Norris]

Until this thread I had never had any trouble with Viton seals on the 
rotating parts. However, I just finished a total tear down of my race engine 
and noticed the bellhousing crank seal had a ragged edge on the inner lip of 
the seal. The outer lip looked new. The crank surface was in good shape and 
lightly polished when
installed. Also I lubricated it well. Upon closer inspection there was a 
little brown track of seal material on the crank sealing surface matching 
that of the ragged lip.
It was not leaking. The engine was run between 6 and 7000 RPM when racing. 
The rear crank seal looks perfect and was not leaking. I have both types of 
seals in my parts inventory so now I'm in a quandry as to which to use.
However, this is just a comment on my observations. I am NOT seeking advice 
on this so save your key strokes! I will resolve it.

Rick Norris
#36 Sunoco Corvair
www.corvairalley.com


> When I was in the machine tool business, we tried not to run lipseals more
> than 1,000 surface feet per minute or excessive heat would build up.  At
> 1,500 SFM the heads would get so hot you couldn't touch the front 
> retaining
> caps or get burned.  Over 1,500 SFM we put labyrinths and air pressure to
> keep things cool. Many times we would remove the springs from the seal 
> lips
> to reduce friction and lower temperature. All our seal surfaces were 
> ceramic
> coated and polished in a plunge motion, not cross hatched.
> A Corvair crank seal at 5500 RPM redline is going 4,320 SFM.  It's no 
> wonder
> they burn up!  At 2750 RPM highway speed, the seal is still running 2,160
> SFM.  Way too hot!  I don't know what to do to improve things other than
> making sure the crank gear seal surface is smooth and polished.  A
> speedi-sleeve is probably a good thing as they are very smooth.  Maybe
> removing the spring from the lip would help reduce friction.
> Clark Hartzel