Cometic rear main seal vs...

Marcohotrod said

The area on the crank is not cross hatching, it is directional grooves. On a used crank we use fel pro rubber or neoprene or whatever they are made of, not rope. A crank that has run for many miles with a rope seal - the area is smooth, no need to buff it down more.

Click to expand...

That sounds like my crank, a forged one in a 1967 273, never been torn down except when I did it last year, with what looks like the original rope seal there. I actually would prefer to use a rope seal but only if I can get the original type. Although Moper says he has great results from using the new ones. I wish I could be that confident, but as I have already bought this Cometic one, I think I will use that. I was just a bit uncertain about the grooves. Yes I knew they were not really cross hatching, I just didn't know what the real name was, or how they actually worked. I thought they were designed to provide a rough sealing surface for the rope, whereas a rubber lip seal works best on a smooth surface.