<VV> Crank seals
Clark Hartzel
chartzel at comcast.net
Mon Feb 13 20:45:44 EST 2012
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
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