Author Topic: 440 Rear Main Seal Problem  (Read 7220 times)

Offline troutstreamnm

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440 Rear Main Seal Problem
« on: April 04, 2015 - 11:26:02 PM »
Hi All,
Just fired up a rebuilt 440 today and the rear main seal leaks like a sieve  :swear: The shop that built up the short block use the standard Fel Pro kit and now I was told alot of problems with the RMS are happening with this kit.  Not sure if this is a kit problem or a machine shop problem.  None the less, I've got to fix this.  What's the best way to deal with this now that this engine is in the car and is there a GOOD RMS kit I should install?  This is a 4-spd car BTW.  Thanks for any help.
08 SRT-8 Challenger
71 GA4 Challenger
70 FK5 Charger 500




Offline cudabob496

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72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Chryco Psycho

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Re: 440 Rear Main Seal Problem
« Reply #2 on: April 05, 2015 - 12:51:54 AM »
I agree , the new Fel Pro RMS is tough to work with , the seal is good but the side strips , now pipe cleaners simply do not work , you need a seal kit with the fiber side seals or reuse the old ones if you have a set . I have used Right Stuff sealer now & put a bead between the block & seal plate inside the crankcase to insure the sides seal up fully

Challenger - You`ll wish You Hadn`t

Offline AussieMark

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Re: 440 Rear Main Seal Problem
« Reply #3 on: April 05, 2015 - 04:36:08 AM »
Is there problem free seal from another gasket company or a rope seal available?

Offline troutstreamnm

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Re: 440 Rear Main Seal Problem
« Reply #4 on: April 05, 2015 - 09:29:15 AM »
I saw an older post that Mancini Racing has a good RMS kit, but it wasn't specific.  Does anyone know what kit from MRC works?  I see they have many different kits available.  Thanks
08 SRT-8 Challenger
71 GA4 Challenger
70 FK5 Charger 500

Offline 734406pk

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Re: 440 Rear Main Seal Problem
« Reply #5 on: April 05, 2015 - 10:38:30 AM »
I saw an older post that Mancini Racing has a good RMS kit, but it wasn't specific.  Does anyone know what kit from MRC works?  I see they have many different kits available.  Thanks

I haven't used the MRC kit but a few friends have with good results. There is a kit that comes with a billet lower seal carrier and rubber (Viton?) seal halves. Check the crank seal surface for rust pits etc from sitting with the old rope seal if this is a vintage crank. Do you have access to a car lift?
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline cordodge

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Re: 440 Rear Main Seal Problem
« Reply #6 on: April 05, 2015 - 10:56:02 AM »
i had an issue years back when a friend of mine bought two 426 wedges out of an boat we rebuilt one of the two for his lobster boat. everything worked great but it leaked about a liter of oil on the first day out of the RMS seal, so i took it out flipped it over put a new seal in and the next day the same thing. removed it again and took a closer look and realized the the two engines ran the opposite way in the same boat and the one we rebuilt the crank was actually meant to turn the other direction which meant the little fins on the crank where the rear main seal went was actually pulling the oil out. never even thought about it when we were looking at which one to rebuild, firing order i think was 12756348. had to use the crank out of the other one and he ran that thing for quite awhile till he switched to a cummins.

thx Bruce
1970 challenger 95% done
1969 roadrunner in progress
1969 D-100 13,000 mile truck
1969 L-700 tilt cab in progress
2007  Dodge Ram 4x4
2017 hyundia Santa fe ultimate
1977 VERY UNDERSTANDING WIFE !! 😇

Offline mopar jack

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Re: 440 Rear Main Seal Problem
« Reply #7 on: April 05, 2015 - 12:07:14 PM »
I'm using the Mancini kit with no problems. It uses viton O ring material for the side seals in the retainer and looks like a better fix than the pipe cleaner seals in the other kits. However I had good results with the pipecleaner set up too. It just didn't seem practicle. The Mancini kit is more exspensive than the Fel pro because of the billet retainer.

Offline Chryco Psycho

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Re: 440 Rear Main Seal Problem
« Reply #8 on: April 05, 2015 - 01:02:12 PM »
make sure the seal is facing inward , this could be the whole problem .
 you cannot install a rope seal without removing the crank though

Challenger - You`ll wish You Hadn`t

Offline 734406pk

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Re: 440 Rear Main Seal Problem
« Reply #9 on: April 05, 2015 - 01:59:46 PM »
i had an issue years back when a friend of mine bought two 426 wedges out of an boat we rebuilt one of the two for his lobster boat. everything worked great but it leaked about a liter of oil on the first day out of the RMS seal, so i took it out flipped it over put a new seal in and the next day the same thing. removed it again and took a closer look and realized the the two engines ran the opposite way in the same boat and the one we rebuilt the crank was actually meant to turn the other direction which meant the little fins on the crank where the rear main seal went was actually pulling the oil out. never even thought about it when we were looking at which one to rebuild, firing order i think was 12756348. had to use the crank out of the other one and he ran that thing for quite awhile till he switched to a cummins.

thx Bruce

Back in the day of counter rotating Chrysler marine engines, the knurling on the crank was cut according to rotation. Other than that the cranks were identical. A crankshaft for a RH 440 should be extremely rare today, but you never know until you check. Good point!
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline cordodge

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Re: 440 Rear Main Seal Problem
« Reply #10 on: April 05, 2015 - 02:30:36 PM »
Back in the day of counter rotating Chrysler marine engines, the knurling on the crank was cut according to rotation. Other than that the cranks were identical. A crankshaft for a RH 440 should be extremely rare today, but you never know until you check. Good point!

hey, yeah for sure, it was about 20 years ago and thinking about now i believe when we tried to start it we must of had the RH starter as i recall having an issue but it never really sank in that we had a left and a right starter as well. i do recall that the engines had some neat stuff like the water cooled manifolds, and brass pumps as it was a closed system and i think if i remember right the push rods seemed to be beefier and oil pick-up was a swing style. i believe they were 1964s. not sure what he did with them should ask as they had almost no hours on them.   Bruce
1970 challenger 95% done
1969 roadrunner in progress
1969 D-100 13,000 mile truck
1969 L-700 tilt cab in progress
2007  Dodge Ram 4x4
2017 hyundia Santa fe ultimate
1977 VERY UNDERSTANDING WIFE !! 😇

Offline 734406pk

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Re: 440 Rear Main Seal Problem
« Reply #11 on: April 05, 2015 - 02:56:20 PM »
Most of the marine engines were built from high performance automotive components. 426 wedge were built with small port heads (not Max Wedge) for operation at 400 rpm or less. The hash marks on a RH crank look like this: ////////. Pulls in with rotation. Automotive slant is the other way. (sorry no key for that one). Hope this helps!
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline Chryco Psycho

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Re: 440 Rear Main Seal Problem
« Reply #12 on: April 05, 2015 - 03:55:52 PM »
\\\\\\  :bigsmile:

Challenger - You`ll wish You Hadn`t

Offline 734406pk

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Re: 440 Rear Main Seal Problem
« Reply #13 on: April 05, 2015 - 04:44:00 PM »
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline smos001

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Re: 440 Rear Main Seal Problem
« Reply #14 on: April 07, 2015 - 04:36:39 PM »
I went through this problem last year on my 383 rebuild. We tried everything including a new crank and 4 different seals and retainers. After doing a lot of measuring and data collection we found that the bolt pattern for the rear main seal was off slightly to one side. This offset caused one side of the seal not to press completely against the crank. We ended up pushing the OEM rear main seal retainer to the weak side by the distance that it was off. The OEM retainers have a lot of slop to work with.
 It was a lot of math but it worked. I have a leak free seal.
I know that everyone hates the pipe cleaner side seals. But the issue is not always the side seals. We tried every different type of seal and the sides were not leaking. If you do everything right it should not leak unless you have a component issue. Measure everything!