Dave, I am fully aware of the studs and the havoc they can wreak on a Mopar. ex ( enlarging thrust cap bolt holes to 17/32" for thrust cap alignment) So yes, I have scalloped the retainer out around studs and nuts. The Mancini cap was also relieved as it extra material in that vicinity, and would definitely hang up there. Furthermore, when I take this apart I always witness the mating surface and how the thin layer of sealant is completely squeezed out and leaves the shape of the retainer. Pics on the way. Thanks though, J.Rob

Monte, So you turn the seal 90* so the seam/parting line will be at the 12 0'clock and 6 o'clock position? I am willing to try anything at this point but fail to see how this helps.

The seal lips are facing inward-believe me when I first took it apart I was hoping I had it backwards for an easy explanation. Thanks though, J.Rob

Wow just read through all of it. Is your crank an Eagle?(Nevermind I see it is OEM) My block is a '68 that was cast on Hallowe'en! WTF? J.Rob

I'm sure u did this, but I'll ask anyway. Is the seal retainer flush with the back of the block? Maybe there is a misalignment issue. Last one I did, I put the seal & retainer in with no crank & checked to see how the parting lines lined up.

Did this. No crank in block, seals in, everything was nice and round. Parting lines almost not detectable by finger. Did this twice actually. Thanks, J.Rob

When you put it in the block with no crank.. did you have the
side seals in it.. I have seen where the retainer was cut shallow
on one side.. it forces the retainer over... this was a after
market retainer

No side seals were in, but I also fill the side channels with RightStuff when I install--so no side loading is present in this case. J.Rob

I'm on the edge of my seat with this one. I am actually dealing with this exact issue right now. I have assembled several Big Blocks over the years and have never had a leaking problem at the back of the block. The block and seal retainer I'm using was used in the past with a factory crank and no leak. The difference now is a Ohio Crankshaft 4.250 crank and BRC aluminum main caps. I am running it on a run stand. It doesn't start leaking until the oil get's hot and then it only leaks when you rev it. When I initially assembled it, I was a little concerned with the side seal on the one side of the cap because it didn't seem like it slid in all the way so I figured that was the problem. When I pulled the pan off to have a look I noticed witness marks on the windage tray and the gasket was chewed up there from the main cap studs. I then figured that this must be causing a leak at the back of the pan. I clearanced the windage tray so it wouldn't hit the main studs replaced the side seals put a light coat of silicone where the retainer meets the block, a small dab of the Right Stuff on the ends of the rear main seal (I stupidly didn't change the seal). I ran it again no leak when it's cold as soon as the oil gets hot and thins out when you rev it it starts dripping. I can't tell where it's originating from because everything is so clean and the Valvoline VR-1 is colorless. I bought a bottle of dye to put in the oil and will check with an UV light to try and pinpoint where it's leaking from. This is driving me crazy due to limited time to work on this stuff. I'm hoping to run it tonight. If I learn anything I will report back. Good Luck and thanks for starting this.

I used phosphorescent dye (works with a black light) to check a set of heads. They lit up like a Christmas tree at every crack. If there is a dye like this that can be safely used with motor oil, you could trace the leak easily.

There is a small oil pressure relief hole drilled in the block in the rear. It relives full pressure from the rear seal. Went thru the same problems a couple of years ago on a low deck motor, fought it all year found relief hole and cleaned it out Problem solved

I am not aware of this hole. Does anyone have a picture that shows the location of this hole?

I just checked a '70 440 block I had bare here. There is no hole that I can find? J.Rob

Never seen or heard of a hole, that relieves pressure off the seal.

Ramm, just try the sealing ends 90* apart can't hurt. And like I said, I never glue the seal in the block or retainer. Just place it in there. Place lower half of seal, put crank in, then take upper half of seal and work it around crank until you parting lines at 90*. Then put the retainer in

plug at the cam tunnel just above the rear main seal seeping?, damhik especially the welch plugs.

I know this might be a stretch but what are the odds of the seal journal on the crank not being in line with the rest of the crank? or the other way. the crank seal retaining area not in line with the line bore? i wouls at least try to check that part on the crank, seeing that that might be the 1 thing that has changed in the previous setup.

did we put engine oil dye in it,and run with black light

I would think this would show up when I lay crank in mains and set dial indicator on seal journal and it displays .0009" out of round. I called Eagle today and they say they keep it at .0005" or 5 tenths. They were of no help of course.

Also when I have had the crank out and installed the retainers-the seal halves line up nicely and I mean round and inline with each other. J.Rob

yeah that should have been good at that point. another thought would be to look at the oil feed hole on the crank for that main. is it pointed to that direction? maybe drilled incorrectly so that it would direct oil flow towards seal? seems at this point like oil is aiming directly at the seal instigating the problem.

Plug the valve covers up and put some air in it and try soap bubbling the seal area. I know of several top shelf mopar engine builders who are ready to rip their hair out right now over these dang seals.
Todd

i like that idea. i'll try to remember that one in the future.