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.
and Thank you sir, I get tired of trying to help and usually being ignored.
