Rear main seal problems
 

I don't want to mention brands, but I used an aftermarket seal on a friends 400 and ran into some problems. The seal crystalized and fell apart. I then tried another seal on the market and it started tranfering rubber to the crank. I tried using another one of those seals with different lube on it and it still transfered rubber. I've used the Felpro MS-40032 before(with some shimming) but I wanted to try these seals. Anyone else have these problems? Cures? I'm tired of pulling this engine out.

I used the rope seals on mine and they work pretty well (knock on wood) I just have to wipe off the bottom of the oil pan when i change the oil. Its crome so it just wipes right off. and this is with 10w30 mobil1

Wow!! What kind of condition is the riding surface of the crank?? Did you put some grease on the seal for installation break in?? What are you doing for a PCV system? Do you have sealed breather/valve covers and a PCV valve in the valley pan??

My 1986 Ho Racing seal (black) never did that. My BOP seals never did that. You have entered the twilight zone. Factory rope is YOUR safe bet huh. :ranger: HIS

Try the BOP seal. They are viton, which is a better heat tranfer material. Felpro uses the same material with the race kit seal.
Have installed dozens without issues.

What do you mean fell apart? Never saw a seal do that in 35 years. Get away from rubber seals with todays engines.

The PCV system is stock. The crank surface is polished and in good shape. I'll see if it's still laying around and post some pictures. I did lube the seal before the cap was installed. The seal cracked into little pieces and when the cap was removed little chunks were everywhere. I'd never seen anything like this either.

The only reason I can think of that could cause two different brands of seal to crack into little pieces is too much local heat. How does #5 main look?

Measure the groove depth in the block and the groove depth in the cap and make sure they're the same. On my 400, the block side of the groove is about .013 shallower then the cap side of the groove.

need to replace mine.
 

dose anyone know the part # for a viton rear main for the 455 (3.25) can it be found at a local parts store? i know i can order it but would like to get it in town.

Strictly thru the Pontiac Engine Pro parts shop of your choice or B.O.P. Engineering. Local auto parts places always want to sell you a 460 ford seal that doesn't work. Also check the serations on the crank to make sure they do not have a sharp edge. Had one edge one time that was ripping things up.