440 Rear main seal question

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Tejas

Tejas

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Hey guys, I'm going to build a 440 for a 69 Dart GTS in a few weeks. I'm gonna use the stock forged crank which has a crosshatch in the rear main seal area.
Back in the day I learned that the crosshatch means that it must use a rope seal for the rear main seal.
Has anything changed over the years to where I could use a more modern seal or do I stick with a rope seal. It had a rope seal when I tore it down.
Thanks!
 
I prefer the rope myself.
I believe the serrations / knurl / cross hatch are polished to use the lip seal. Either way you got to do it right to be successful.
Use the search, I'm sure several threads will show up.
 
There's no reason you can't use the common replacement rubber seal with the stock crank knurl. I've had better luck though with the Viton main and side seals that are available now. Or, use a rope - whatever you're most comfortable with.
 
When I had my 340 crank re-chromed the owner of the crank shop told me that the knurl is there to sling the oil away from rear main seal area as rope seals were prone to leaking. My crank had a severe groove in the seal surface from rope seal wear and was re-chromed to return it to the correct seal diameter and the knurl was chromed over. I now have a lip seal which is leak free, and will work fine with or without the knurl as the sealing ability of the lip seal is much better than a rope seal.
 
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