Rear main seal leak?

[69Bee]

While cranks have had the serrations for a while now, they were more prevalent with the rope seal. I have seen a lot of neoprene seals with the serrations too, and they do not cause a problem. They will not cut the seal because of the smooth surface, and they are cut so that the oil will be pulled into the engine when it is running. When the engine is stopped, there is no oil pressure to force any oil out thru the small channels. The only way it should leak is to use a marine reverse rotation crank in a car engine because the serrations are cut in opposite direction, and oil can leak under pressure.

 

[Daves69]

I know I read an article that recommended polishing the knurl smooth. No idea where to find it now.

The service bulletin doesn't say to......
http://www.hamtramck-historical.com/images/TSBs/1970/D70-9-3 page1.jpg
http://www.hamtramck-historical.com/images/TSBs/1970/D70-9-3 page2.jpg

 

[moparnation74]

I know I read an article that recommended polishing the knurl smooth. No idea where to find it now.

The service bulletin doesn't say to......
http://www.hamtramck-historical.com/images/TSBs/1970/D70-9-3 page1.jpg
http://www.hamtramck-historical.com/images/TSBs/1970/D70-9-3 page2.jpg

Great bulletins! Thanks for posting....

Every crank on my rebuilds gets polished including the knurl area. That will give peace of mind of no future issues. Experienced machine shops in Mopars know this but not all do.

 

[69Bee]

I know I read an article that recommended polishing the knurl smooth. No idea where to find it now.

The service bulletin doesn't say to......
http://www.hamtramck-historical.com/images/TSBs/1970/D70-9-3 page1.jpg
http://www.hamtramck-historical.com/images/TSBs/1970/D70-9-3 page2.jpg

I would not recommend doing that; polishing the knurls smooth. If a groove is 0.005" deep, you would have to remove 0.010" from the seal area, and create a leak problem where there wouldn't have been one. I also polish the seal area when I polish cranks, but just to clean it up, not to remove serrations.

 

[moparnation74]

Polishing and removing are two clearly different things....I relate polish smooth as in cleaning up lightly making that area "Smooth" but not removing....That is exactly what I have the machine shop do...

I can only imagine what my machine shop would say if I asked them to remove the knurls, lol....

 

[69Bee]

Polishing and removing are two clearly different things....I relate polish smooth as in cleaning up lightly making that area "Smooth" but not removing....That is exactly what I have the machine shop do...

I can only imagine what my machine shop would say if I asked them to remove the knurls, lol....

I was responding to the comment made by Daves69, not your comment. If you read what I wrote, I agreed with what you said.

 

[Daves69]

I would not recommend doing that; polishing the knurls smooth. If a groove is 0.005" deep, you would have to remove 0.010" from the seal area, and create a leak problem where there wouldn't have been one. I also polish the seal area when I polish cranks, but just to clean it up, not to remove serrations.

FWIW, I prefer rope seal.
No, I don't condone the removal of the knurl. The article as I recall focuses on the edges raised in the knurling process. Nobody "polishes" .005" off anything to my knowledge. Maybe a couple tenths at best.

 

[moparnation74]

I was responding to the comment made by Daves69, not your comment. If you read what I wrote, I agreed with what you said.

My previous comment was in relation to dave69, the one you quoted earlier...Just wanted to clarify my end...ease up bro we are all friends here...