I'm struggling with some real stupid stuff on my newly built Gen II Hemi.
The rear main appears to be leaking pretty good. Looks to be coming from between the motor plate and block (I'm running a Lakewood blow-proof).
I used the "Best Gasket Co." brand rope seal recommended by several Moparts members for use with a knurled crank (which I have). The seal came with highly detailed instructions which I followed to the letter. Seal was really tight on the crank; lots of drag. My block is a new MP mega block with the billet seal retainer. Motor has about 2 hours run-time on it.
Has anybody else had this problem? Recommendations??? Hell, maybe it's an oil gallery plug leaking... Any way to tell between the two, other than pulling it all apart?
Oh, I do have a PCV hooked up. How do I tell how effective it is? Could a problem there create a rear main issue???

As you know it has to come apart again (unfortunately). not from the PCV (lack of)

Have you measured your billet seal retainer compared to a stock one. I've seen aftermarket seal retainers machined wrong.

Do you have a factory crank or aftermarket?

I'm using a stock Hemi crank that has the knurls on the rear seal journal.
I didn't measure or compare the seal retainer to a stock one, but the rope was evidently tight against the journal (significant drag on crank after seal was installed).

To begin with, having to use a rope seal on a factory knurled crankshaft is a falsehood. The origin of this info is is unknown to me and very puzzling as to why it's still suggested on this board

If it's possible to see up into the bell-housing I'd suggest pulling the distributor and have someone spin the oil pump with a primer rod while trying to locate the leak before pulling the motor.

What one member had good luck with, is a rope seal with an aftermarket crank.

Billet rear main seal retainers have been known to be machined off center. Which means lot's of friction on one side, an oil leak on the other.

My MP block was manufactured in Nov. '13 and I'm using the billet seal retainer that came with it. Has the offset problem showed up in stuff this new? Did anyone find a problem with the MP part in particular?

Is it a World block ?

Did you install the retainer before putting in the crank to check the alignment? The tip off that you were faced with an issue would have been the crank being really hard to turn if installed the seal correctly.

I don't know how it would happen but the seal side of the block could have been machined wrong , Dan Costello had that issue with a Hemi he did for someone , finally tracked that leack down to the block being machined wrong .

I think it would be a World block. P/N was P5153862AB. Was manufactured just over a year ago. Is that the right period for World blocks?
The retainer was installed in the block, as received.
The crank was hard to turn after adding the seal, but I assumed that was standard for a rope seal.
As for the retainer, should I remove it and compare the geometry to a stock version?

Your awfully fixated on the rear seal being the source of the leak..... why don't you find out exactly where the leak is coming from and go from there?

Roadhazard,
I'll try to do that. The Lakewood bellhousing and block plate make it pretty much impossible to see anything in that area. Oil is seeping from between the block and block plate.
If it turns out to be the seal, which of your kits do you recommend? I see that Mancini has two different ones.

Uh, yes with the block plate it's going to be real difficult to pin something down.

If you end up pulling the motor I'd still suggest running the oil pump primer to search for the leak before tearing it down.

There is only one kit available now, Part #9383....... unfortunately Part #9440 is no longer available.