Everyone knows that old engines leak oil. Some leak
worse than others because of inadequate gaskets, poorly designed matting
surfaces but most of all main seals. The only way to seal the crank-shaft was
with rope seals or packings. If you remember, we used to take a rope seal and
soak it in oil over night before we installed it. The outcome no matter what, either
right away or a little latter the damn thing leaked.
In our new flathead motors we fixed that. We designed a
rear main that incorporates a modern lip seal, and in the front you can use a
lip seal in the cover. Here is the only problem.
On the original surface, designed for a rope seal, look
carefully at the seal surface on the rear of your crank. You should notice a
built in spiral. That is no good for a lip seal. A lip seal requires a smooth
surface. A spiral surface will act like a thread constantly screwing itself
through the new lip seal and prematurely wearing it out. So, to fix that simply
take your crank to your local crank grinder and have them grind the spiral
(seal surface) down to a given dimension. Then you will have the perfect seal
surface for our new lip seal.
On the front of the crank, that seal surface is a sleeve
pressed on to the crank. We will supply a smooth ground sleeve perfect for a