500 Stroker REAR MAIN Seal

[69charger440]

New motor 500 Stroker

The rear main seal keeps blowing out. I have two breathers hooked up to the back of the carb from the valve covers. When I remove a breather from the car while running the rear main seal pours out oil. As soon as I put the breather back in it quits and only drips about two drops a minute. I did a leak down test and compression test. Compression is at 158 -/+ 1, in all holes. I have 6 holes with 12.5 % leak down and one hole at 10% and #4 at 15%.

Kinda at a lose with this. Thinking maybe the rings haven't sealed yet and causing a lot of crank case pressure. NEED Assistance.

Also this is the second Rear main seal. I blew one out on the Hiway and replace it last night and started it up today to realize I still have a problem.   

[General_01]

Not sure if this applies, but I had a 383 stroked out to a 496 using the 440 Source kit. My builder told me that these kits were notorious for leaking at the rear seal because of the knurling on the crank for the main seal. I think he said it might be too rough for the new rubber seals. He said he had to redo a couple of rear seals for guys when these kits started coming out because of this. They figured it out and he started having the knurling redone and didn't have a problem with it since. I also had a new billet rear main seal retainer. He was not a fan, but put it in for me. This was a few years ago so I am not sure if it is still an issue with the kits.

[Challenger340]

Sounds like you may have excessive blow-by ?...nonetheless...the rear main should still seal ?
usually,
if the lip is making good contact all the way around on the crank...the leaky compression just aids the lip seal by pushing it down harder on the crank...unless the lip seal is backwards ?
apologies, not calling anybody down, I'm sure it's in right...just saying for explanation purposes vrs compression, and regarding seal orientation if it is contacting the Crank all the way around ?

2 things;
1.) are you installing the seal flush, or, offset from the parting lines of the seal housing ?

2.) related to #1.....with BB Mopars .... it is important when assembling, to observe the upper seal half "lip contact" on the Crank when it is installed in the Block, before installing the lower seal & retainer.
because,
on many blocks the groove where the Seal resides in the Block is NOT concentric with the crank...the seal relief cut was a separate machining operation on the block after the Line Boring, and they missed lots ! Back in the days of rope seals...nobody cared much.
hence,
if you look....the seal might be making good contact with the crank on one side.... but barely touching the crank(if at all) on the other side.

This is why it's a good idea to look for this condition first when assembling before installing the retainer, and offset the seal from the parting line...then using the Retainer with the other seal half installed to DRAG the offending upper half OVER sideways, to make contact with the crank before tightening the bolts.

I feel your pain...no fun
keep us posted.

[69charger440]

This is a 440 source crank...

I installed the rear main seal halves by rotating the seems so they were offset to the retainer and block seems. I installed the rear main seal with the "big lip" towards the front of then engine.

My plan is to keep it in as long as it is only dripping for now. I am hoping if I drive the car some more the rings will seat better and reduce so of the pressure inside the block.

[fy469rtse]

Had a similar problem with a friends stroker 440, once the engine had warmup , oil started pouring out. We actually thought we had forgotten gallery plug, turned out as above in this thread crankshaft 9 thou out to one side, there is an over size seal that , orange in colour , it fixed this problem, how much has your engine or how long has it run , maybe rings will see in ,interesting that stopping pressure release through valve covers so blow by built up on seal, pressure helped oil seal possibly in backwards, but I would try the over size one I think from Mancini racing with new rear cap that uses o rings instead of the cardboard slides. When you put it in just make sure it's facing the right way, seen eagle cranks without the knurling, terrible,
Use plenty of sealant to sides of cap, good luck post later how you got on

[69charger440]

Had a similar problem with a friends stroker 440, once the engine had warmup , oil started pouring out. We actually thought we had forgotten gallery plug, turned out as above in this thread crankshaft 9 thou out to one side, there is an over size seal that , orange in colour , it fixed this problem, how much has your engine or how long has it run , maybe rings will see in ,interesting that stopping pressure release through valve covers so blow by built up on seal, pressure helped oil seal possibly in backwards, but I would try the over size one I think from Mancini racing with new rear cap that uses o rings instead of the cardboard slides. When you put it in just make sure it's facing the right way, seen eagle cranks without the knurling, terrible,
Use plenty of sealant to sides of cap, good luck post later how you got on

Pulling engine tomorrow, will inspect engine bearing and rear main seal. Ordered new rear main seal and mancini oil ring sides. Probably wont receive the Mancini part for a couple day. Also installed vacuum pump, just waiting on my catch can from summit to arrive. Hopefully all ends well. Going to be really upset if this next rear main seal goes out.. Thanks for the input

[BrianShaughnessy]

The stroker crank I have has no fillets cut for the seal at all..   so I was gonna go with the overpriced fel pro orange rear main seal.

I'm curious if I can find one of those old MP anti leak rear main bearing kits that had the groove cut to relieve oil pressure off the rear seal.   I used to have one in the garage... but I think I wasted it on a 2.2 turbo motor ( same main bearing size! ).

[69charger440]

The stroker crank I have has no fillets cut for the seal at all..   so I was gonna go with the overpriced fel pro orange rear main seal.

Thats the seal I am going with this time. Almost tempted to go with rope seal.

[69wannabe]

Had the same problem on my 493 kit I got from mancini. It wasn't pouring but it was a steady drip. I pulled the pan and swapped the rear main and put a new seal retainer in and that didn't work after a couple of times pulling the pan. Pulled the engine and took it to my local machine shop. He sent the crank off and had the rear main seal journal trued up and said that should do it. Put it back together and after a little run time it was dripping again. I think I pulled the engine three or four times!! Finally an old guy I work with said try a rope seal so I thought why not, what did I have to loose?? Put a rope seal in with new 440 source side seals and my factory seal retainer and I will say its 98% fixed. I still have a drip or two but nothing like a constant steady drip, drip, drip. I would love for it to be dry as a bone under there but it's good enough after pulling the engine so many times and not having any other luck with it at all. I can deal with a drip or two here and there but not a constant drip while its sitting idiling. Good luck with it!!! I hope you get it straightened out soon!!!!

[john108]

Is the rope seal still available?

[69charger440]

Is the rope seal still available?

Yea you can get them at AutoZone. Going to give it one more try with the Fel Pro seal, if it fails then its time for rope seal..