To clear some technical confusion, the purpose of any rubber seal having helix grooves is to physically throw the oil back in towards the engine... if the seal is installed reverse (with the grooves facing the transmission, it will physically pump oil out of the engine.
It make no difference if the crankshaft has knurls or not... they are there to keep a small amount of oil on the shaft where the seal makes contact.
Rope seals were simple, back in the day, to install and low cost to manufacture... as well as the casting grooves for the seals were not dimensionally held at tight tolerances... where as rubber seals more commonly need a tight fit into their retaining grooves.
I'm a former gasket engineer from a major company... these are common questions being asked.
Thanks for the clarification. I had a feeling the rope seal statement needed fact checking.
I know this subject is beat to death on here but I have found so much conflicting information, I am beginning to feel like I know absolutely nothing.
One last thing - good idea to cut the retainer down .010 or not? I know that will create a bit more "squish" on the seal but will the non-concentricity become an issue?
