[Dave in MN]

Terry is explaining my experience with modern main seals. When the crank is prepared for a modern seal, the seal surface should be cut before sending to the crank grinder. When at the crank grinder, ask them to index the rear main journal from the seal surface. The two surfaces should be concentric within .001" or less. Another point to remember...when polishing the crankshaft seal surface spin the crank in the direction the crank turns in the engine. I have found that modern seals, both front and rear will fail if you don't.
Good Day!