I need some serious help here. The battle I have been having with this rear main seal is going to affect my health-seriously.

The saga begins: Customer brings previously rebuilt (18 years ago) 440 in for freshening/updating.

It is a 440 with a NEW stock stroke Eagle crank, Eagle H beam rods, reused Wiseco pistons, 915 heads etc...

Customer has a 69 RoadRunner 4 spd car and he is the original owner.

1st attempt: Engine runs great on the dyno but seal leaks a few
drops.

2nd attempt: I figure I missed something with his original retainer and proceed to get pan gaskets ordered so I can take pan off and "fix" rear main. I remembered that I did not have any venting or breathing in the valvecovers except for his original PCV valve hooked into the back the carb. I figured I generated too much crankcase pressure the first time. Hook engine to dyno and fire it up with open valve covers--no leaks until I complete one short pull. Engine makes great power but leaks again--same spot.

3rd attempt: Customer is awesome and supplies a Mancini billet retainer. I verify endplay .005", crank seal journal out of round .0013" and assemble with new Victor rubber seal. All looks good and normal. Re-dyno. Warm engine up---leaks worse than before. No pulls are performed.

4th attempt: Tear down, remove crank, install rope seal left over from a Pontiac gasket set. Polish seal journal with highspeed crank polisher. Feels better, looks better. Re-dyno. Leaks same as before. Install pressure gauge on dip tube and really look for signs of blowby none detected.

5th attempt: Tear down, hand grind with pencil grinder "anti-leak" grooves into rear main. The grooves point forward and this looks like it may do the trick. Prepare different rear main retainer (OEM)surface .005" in cap grinder (per my usual prep). Install another new rear main rubber seal with aviation sealer under rubber halves instead "RightStuff". Re-dyno ran engine 1300-1500 rpm for 15 minutes while I layed on the floor with a flashlight watching rear main. On the 13th minute a leak began right before my eyes. Remove engine from dyno and back on the stand. All signs are pointing to a rear seal area that is too rough or something.

6th attempt: Send crank to crank shop where seal journal is ground .005" and built back up with chromium ($$$$$) and finish ground. Crank shop assures me he has seen this many times and this is the only fix.At the same time block is torn down and re-honed/ re ringed to rule out blowby. I check the seal surface for out of round this time it is better (.0009") This time a new Fel-Pro "red" is installed and carefully (You have no idea) put into place.Back on the dyno and engine runs great like usual. I nervously watch the clock and the floor. 20 mins passes--crank flange and block is bone dry!! I run out of fuel. Get fuel, refire, warm-up, complete pull 4000-5000 rpm. LEAKS!!!!!!!!! Not much but it will not get better by itself.

Conclusion: I have built approx two dozen (maybe more) Mopar big blocks in my life and have never even been this careful and I have never ever had a leak. I have "influenced" the retainer to one side, I have feeler gauged it forward into correct alignment as measured, I have taken every conceivable measure to correct this.I had a small block Mopar leak on me once that was the result of a messed up linebore. It was remedied with a rope seal. I have a Fel-pro rope seal on the way. Short of ordering a NEW Scat crank I don't know what else to try. Keep in mind this thing has a tray and I have effed up 12 gaskets at this point.

This engine was not leaking when it came in and no line hone was performed.

The only thing that has really changed is the new Eagle crank. I am open to any and all suggestions/ experiences.

Surely somebody has gone through this. Yes I have done more online searching and reading than I care to admit. Yes the knurling is in the correct direction as the OEM crank.(It does not have knurling now) Yes it has the crank deflector just like the OEM crank. Yes I have checked the diameter of the seal journal. It is the same as the OEM crank. Yes I have installed the seal retainer with the crank removed from the block twice--it is nice and round and inline for and aft. This is not making sense. Maybe I can't see the forest for the trees? Any and all help sincerely appreciated--J.Rob

Studs or stock main bolts? if studs, #5"s are hitting the back of the pan. Not the main seal at all. Been there done that. Other than that . don't know what to tell ya.

you said it has a tray, so does it have main studs ? if so then chances are the rear studs are holding the pan from sealing at the rear and thats where the leak is coming from.

lol you beat me to it

It's not that the studs are to long , the nuts are longer and hit on the curved back of the pan causing it not to pull down tight. To the original poster: look at the back inside of the pan and see if there are 2 marks where the heads of the bolts are hitting.

Wow that sounds terrible. Keeping fingers crossed that it's got studs and the pan is hitting the nuts. I saw the same issue when assembling my 493 so I was able to fix it on first assembly. The previous owner of it had a "rear main" leak that I'm thinking was probably this very issue.

Sorry, yes studs. Definitely not the pan. Ran the engine and observed leaks without slinging it everywhere. Leak is plain as day running down from the seal journal ABOVE the pan. Thanks though. J.Rob

Not a pan leak. J.Rob

Studs. No witness marks at all on pan. Pan pulls down tight. Thankyou though. J.Rob

Cracked block, at or above the scene of the leak?

RAMM....Welcome to my hell. I feel your pain. What is the cast date of the block you are having issues with? My saga is documented in the following thread.

http://a12mopar.com/yabb/YaBB.pl?num=1424822394/15

I finally gave up and am just going to deal with it as a maintenance item on the car.

D

Do you offset the seal so it doesn't line up with the split between the block and retainer ?

Man thats crazy, i have done more bb Mopars than i can remember and never had a rear main leak. Done many Chevys, Fords and Diesels and i never had a issue.

I would try this. DON'T glue the seal in the block, nor in the cap. Only glue bottom and sides of seal retainer. Seal joints 90* from retainer surface. Never had one leak done this way. And of course I HATE to ask an obvious question.....but you are turning the lip on the seal the right way?

I might suggest that the crank journal for the seal area has been turned down to small? I dunno but Ive heard of eagle cranks having a snout that's to small for a damper by a few thou

He already said it has been cut, rewelded and measures correct

I've seen the rear main studs interfere with the seal retainer. (Actually hit the seal retainer holding it off it's mating surface.)Dave

Starting to wonder about this as well. Only problem with this is the block was dry at the back when I took it apart and I seriously doubt it has ran enough or has been traumatized enough to crack. Thanks though. J.Rob

I have tried both lined up and offset about 3/16". When I install the retainer I can "feel" the seal halves engaging into the retainer/block grooves. Thanks J.Rob

Correct it was measured after attempt #2 and it measured correct. Now it has been ground, welded and reground and left on the high end of the spec. Thanks, J.Rob