Best 440 Rear main seal retainer?

[b5blue]

440 Rear main seal retainer what is BEST? This old factory one has leaked through 2 rebuilds!

[b5blue]

An online search showed every possible combo of answers! I'm going with Mancini's but won't know if it's gonna work for quite some time. (Engine is sidelined for now.)

[metallicareload99]

The factory one has worked ok for me "most" of the time, including the rear main seal I installed I'd think any of the billet aftermarket ones would be an improvement over stock tho. I'm sure you've come across the threads on do's and don'ts of the install

[John_Kunkel]

The original retainer is made of soft cast aluminum and was used with a rope seal. I believe pounding the rope seal into the retainer distorts the channel enough that, when newer rubber seals are used, the seal doesn't contact the crank journal as tightly as it should.

A new factory retainer or an aftermarket billet retainer will better prevent leaks. Also, the leakage might be from the side seals rather than the main seal. I always use RTV instead of the side seals and push a piece of water-dampened pipe cleaner into the fresh RTV to expand the RTV and aid in curing.

[b5blue]

  Thanks guys! 

[69wannabe]

I have had better luck with the factory retainer than the aftermarket one I tried a few years ago. When I was running my stock steel crankshaft I had no rear main seal leaks. After the stroker kit it was drip drip drip. I tried a different retainer then several different rear main seals plus a rope seal too. In 2017 I upgraded to some prepped stealth heads so I pulled the engine and also pulled the oil pan since the rear main was leaking again. Used a replacement rubber rear main seal with the rubber 440 source side seals and a factory retainer but this time instead of putting the seal halves with the mating of the block at the 3 and 9 o clock positions I rolled it in and put the halves at the 12 and 6 o clock positions. Actually recommended by something I found on the net about this 440 main seal leak problem.  After that I (knock on wood) have not had any oil leaks from the rear main. I just recently back in April replaced the clutch kit and was glad to see that the back of the engine and the flywheel was good and dry. Just a suggestion but it did fix my dripping main seal leak.

[b5blue]

  The Mancini rig came yesterday. It has 2 thin strips on each side and came with the seal also. Hard to believe thousands of these were built with 0 issues yet we struggle today sometimes!   

[Challenger340]

We still use the stock retainers with no problems, as mentioned, the factory used rope seals that were very forgiving, the neoprene seals not so much with most of the problem for leakage being the seal receiver groove in the block NOT being concentric with the Crank as it was cut/machined after line Boring of the Mains.
Some tips:
* Mock up install the upper seal half in the Block flush with the parting lines, and a couple of upper Main Brgs.
* Set the crank in the Block
* take a flashlight and look at the seal 'lips' on both sides and assess how well compressed they are against the Crank(one side of the seal will be barely contacting the Crank)
SEE the problem ??

Now when assembling for real..... offset the seal approx 1/4" from the parting line on the offending(poor contact side).... install the seal opposite in the retainer with the same offset.... then gentle wiggle the retainer down onto the crank.... then using a small screwdriver very 'gently" push the Seal Retainer over dragging the offending/non-contacting seal side into contact with the Crank as you tighten the retainer bolts.

*use silicon behind the Seal halves in the Block and the retainer.... seal the sides with silicon as well and trowel with a wet finger(goober)

* Good idea when done Installing Seal/Retainer Crank and Mains....  BEFORE you feed it Pistons and Rods and continue assembly... is to install the Oil Pan with a gasket and fill it with 2-3 quarts of Oil.... then "HANG" the Engine from the front submerging the rear seal in oil.... leave it a few hours and make sure it doesn't leak !
We do this on every BB Mopar we assemble.... because we DYNO every BB Mopar we assemble.... and we don't want any LEAKS !
And as stated.... we still use the stock seal retainers with ZERO issues ?

[b5blue]

Thanks! 

[b5blue]

The old assembly was removed and all was proper so no idea why/where leakage? New fancy retainer installed and I used an "SCE" brand (#26605) main seal. Installed a bit offset, just as the last one was.    I've no way to hang test it but possible later maybe?