Anyone here using the Mancini MRE 220 rear main seal? I have read a gazillion post on rear main seals, and unless I am misinterpreting the advice, I am more confused than confident about installing one. So I bought the Mancini MRE 220, no directions. Watched a video from Mopar Connection, seems like he missed something. I just don't want my Hemi puking oil all over the car and floor. Big blocks are new to me. Would like someone to PM me a phone number, or I can PM mine. I just want to know the best way to install it.
Mancini Rear Main Seal
- Thread starter Bird 426
- Start date
kramer
Well-Known Member
My personal opinion is to reuse the original rear main housing and install a rope seal thats your best bet on sealing up the rear main seal the first time around, if you are going the viton lip style seal route you really should mock everything up on the engine stand and without crankshaft installed and make sure you have the the main seal housing as centered as possible to prevent a leak and even then sometimes thats not a guarantee. If you look into the way the rear main seal originally designed on the big block mopar you start to understand why there are some many rear main seal leaking issues.
I have done a mock up. I think that it is a Viton seal, fits the crank journal well. A hare proud in the Mancini saddle. Very proud in the engine block. Someone center punched the bottom of the groove, will try and work on that. The nurling on the crankshaft has had the high spots polished off.
Thank you for answering. Trying to look at this from more than one angle!
Thank you for answering. Trying to look at this from more than one angle!
kramer
Well-Known Member
Most engines have the rear main seal bore machined into the rear main cap and block so the bore is theoretically perfectly round but on big block mopars the upper part of the seal bore is machined into the block but the lower bore is a cast aluminun piece that is machined seperate from the engine so its usually close but most likely not a round concentric bore so the reason most lip type seals have a difficult time sealing in a bore like that, the factory never used lip seals from the factory on big blocks, the rope seals generally seal alot better in this situation. If your going the lip seal route make sure the lower rear main seal housing is as close to centered front and rear and side to side as possible, you may have to drill out the holes in the cap to be able to shift it around. Also when assembling the lower cap do not put the side seals in until you have the cap bolted down where you want it because the side seals can push the cap around from where its optimum to seal.
Where would I get a rope seal? If I decide to go with one, there is probably an art to fitting one? Seem to be a lot of variables with all 3 types of sealing. Careful eye on assembly. Have a little time, got the wrong main bearings! Can try and do some checking with the old bearings.
I will look this over as closely as I can, see what I have. Obviously, I am an amateur engine builder, first Hemi build. Like trying to drink from a fire hose!
I will look this over as closely as I can, see what I have. Obviously, I am an amateur engine builder, first Hemi build. Like trying to drink from a fire hose!
PurpleBeeper
Well-Known Member
I’ve got a Mancini in my motor, but it’s not better than a stock one. The key is making sure everything fits squarely….it can be off just a few thousandths and be cocked sideways when installed
Hughes Engines has an article on rear main seal installation. Search rear main seals and find instructions for it. Good article.
kramer
Well-Known Member
fourgearsavoy
Well-Known Member
Thanks for the link! I will be using that on my next build.
Gus
I always machine.030 off the new seal housing. It has stopped 2 engines from leaking.
Yes, some say .010. Then there are all the others that say the seal is getting crushed, that's without taking anything off the saddle. This is why it's frustrating, every engine is different. Haven't decided which of my 4 options to go. Think that I will take a road trip for a week and think some more on it.
Never used an aftermarket retainer, rope seal, or the factory side seals. The Viton seal is red. I've haven't replaced Viton seal in my racecar motor over the last 3 freshen ups. Check the factory retainer for being cracked by the bolt holes. Open the holes by 1/64-1/32" to allow the retainer to float right or left allowing the seal itself to center the retainer. Use a quality RTV (I use Ultra Grey) to fill the side cavities. Offset the seal 3/16" or so. Use anaerobic sealer spairingly between the retainer and block. Fill the retainer bolt hole cavities with RTV (not all pans cover this area completely). Make sure the rear cam plug is sealed and not cracked. When in doubt? Add a coating of RTV. Been doing engines this way over 35 years. Never had a leaker.
Doug
Doug
It's going to be a couple of weeks before I get back to it. I have 2 rear main seals, one Felpro for the stock saddle and a brown one for the Mancini saddle. I will get back when settle on my method. I do like #13. Slightly over sizing the holes so that the seal hopefully finds it's center. Will be looking at crush too.
Thanks to everyone for a answering!
Thanks to everyone for a answering!
coronetart
Member
Just finished up a low deck build and tried the Mancini . we found too many variances in it. Stick with the factory retainer. We used it with Fel pro 40240 gasket set and installed as dvw posted and you will have best chance of no leaks. Best
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