Crankshaft question

[blown motor]

I'm fighting a leak in the rear main seal on a 440. Changed it once, it still leaks.  What I'm wondering is could the point on the crankshaft where seal contacts it be in such condition that it won't seal anymore?

[Burdar]

What type of seal?

[blown motor]

I think it was a Felpro. Or maybe a Mr Gasket. But not a rope seal.

[Burdar]

I've heard people say that reinstalling a rope seal stopped their leak.

[blown motor]

I've read about guys using the rope seal. I'm not sure how you install one of those.

[RUNCHARGER]

Anytime I've had rear main seal leaks on a big block it has always been the seal retainer to block where the problem was. I've never had the actual seal itself leak.

[Chryco Psycho]

 I agree , more likely the retainer plate , I clean the area well & run a bead of Right stuff sealer into the corner between the block & seal plate after I install it .

[ignition1]

I ran into the same issues with my rear main leaking, so defeated, but had to redo it. I was told by some old timer friends and read on forums that clocking the seal joints at 2 and 8 helps to align the retainer when locking it down and keeps the seal ends lined up.

How: Install the lower seal in a clocked position (something other than 3 & 9), then install crank, install upper seal with a little anaerobic sealant on the seal mating ends, install the retainer with a smear of sealant on bottom edge (alignment pin not necessary, but helps. The good thing about this method is it is fairly clean), then finally some right stuff sealant to fill the side gaps, razor blade any unwanted stuff when dry.

I also had a billet retainer from Mancini which I also machined off -.010 from the bottom edge for slightly more seal crush, so that the oil pan mounting surface was more even (it was sitting a little proud), and didn't use the supplied rubber strips for the sides just the right stuff sealant. Note: I had to clearance the inside of the retainer plate to clear the ARP bolt heads which was also creating alignment and twisting issues.

This worked for me and I would do the same method again next time

[Ramman]

I've always heard that if you installed anything but the stock type rope seal, you had to remove the serrations on the seal surface of the crank.

[ignition1]

Yes, I have heard that too, I didn't cut the grooves... no leaks so far. I would think it is better since the seal is smooth and possibly last longer than leaving the grooves. That's what I did anyways, maybe someone with more experience will chime in.