Counter Rotation Crank seals

[whitfield]

I thought a seal was a seal ???

Why do counter rotation engines require direction specific seals?

Generally ~ transmission rear seals are good for either direction

In automotive ~ Axle seals are good for either direction

What makes counter rotation crank seals so special?


Ofcourse I do not want to chase an oil leak in my boat so I feal I must use the correct seal....
Just curious as to the why.....

[TRBenj]

RE: Counter Rotation Crank seals

On some reverse rotation engines, the seal doesnt matter- in that case the wick lines to pull oil away from the seal are machined into the crank. If the crank doesnt have wick lines, then the seal needs them or it will dump oil in the bilge. I forget which year this changed on the 351w, but it was sometime around 80-82, and I think the newer engines need the special seal.

[DanielC]

RE: Counter Rotation Crank seals

Many oil seals used on crankshafts have ridges on them that "screw" the oil back into the crankcase. Use them on a reverse rotation engine, and the ridges "screw" the oil out of the crankcase.
www.skidim.com probably has the correct seals.