Anyone know what year Ford stopped using the two piece rope style seal and go to the two piece neoprene?

A couple of us were having the discussion about this situation. I'm changing the rope style seal on my 351m and the cap doesn't have a "spike" to keep the seal from spinning. So we were thinking that the cap was maybe setup for the neoprene seal

Are all the 351m main caps this way?

 

As we discussed in the PM's, I'll check my two M-blocks out today and report back.

 

George Reid's book on the "Ford 351 Cleveland Engines", which includes the M/400, has a picture on Page 22 of the rear main and says "Clevelands were originally fitted with rope rear main seals secured by a pin in this location. Check your main cap and remove this pin if it's still there. If you forget the pin it distorts the new neoprene half-seal."

And I've looked my two blocks and cranks over closely, finding that both my 70's era 400 and the '81 351M both had knurled cranks and came from the factory with the neoprene 2-piece seals. Further, Rusty's '81 M is running a 2-piece rear main seal with no pin.

Does that help?

 

It does...you say Rusty is running with a two piece with no pin. Does that mean a two piece rope with no pin? And was it removed or did it come stock with no pin?

Also, does you 70's era 400 and 81 351m have pins in the cap?

 

No, Rusty nor either of the two blocks on engine stands (70's 400 and '81 M) have pins. Both of the ones on the stands came with the two-part neoprene seal, but I don't know about Rusty as he'd been rebuilt by the time I got him. However, he is running a two-part neoprene seal with no pin - I pulled that engine apart when I got it to determine what I have.

 

Ok, I wasn't sure which seal to use. I'm going to go with the rubber one.

In my previous discussion in the 73-79 forum there was some confusion about the crank being setup for a rope style seal (which I guess means the knurling) and the crank being setup for a neoprene seal (with the crank being smooth).
Does the knurling on the crank mean it should use a rope seal? If all of your engines came from the factory with the knurling and with the neoprene seal then I guess not.

I'm still puzzled about when Ford stopped using the pin caps and the rope seals.
They still offer both types of seals. A lot of the threads I've pulled up about rear main seals in these motors they were dealing with taking out stock rope seals, taking the pin out and caulking the hole, and then converting to the neoprene seal. Then the seal leaking a little, forever So, I'm thinking why would they switch to a rubber one? For an easier install? Seems like I'd rather have an oil free driveway for a couple extra minutes during install.

 

The knurling isn't much, and both cranks that I can see have them. And they had neoprene seals. I've built several engines and always used neoprene. And will continue to do so.

 

Have you ever seen caps with the spike in them and had to remove it? Even with other motors?

 

I saw the spike on the 1947 Chevy 216.5 I rebuilt in 1964, and used a rope seal, which was what was typically used then. Since that engine I've not seen it.

 

Cool, thanks for the help? Have some reps

 

Thanks! Happy to help.

 

While I had my 351C out I decided to reseal the front and back. My 71 had a rope seal and pin. I drove the pin out of the oil seal groove and installed a two piece neoprene seal. It's still out so I don't know about how dry it will stay yet