Hey Guys, I have a 472 hemi built by Stanton Racing(Gary Stanton), and I'm right in the middle of a rear main oil leak issue dispute. I'm being told my MP World Hemi block has a casting/maching flaw that has the rear main seal bore off center with the crank bore... And after two attempts at fixing, I'm told they don't know what to do that this is a block warranty issue that they can't find anyone to talk to about warranting this boat anchor???? He tells me he builds all MP crate engines now and he has no contact for warranty issues for MP????? Should I call [censored].... If anyone has any contacts about MP warranty issues would you please chime in or PM me? We all know this stuff isn't cheap and now I'm pretty pissed off. People toot their own horn till the rubber meets the road then they say I don't know what to do.... Really?!?!?!?! Is it that simple to dismiss your screwups these days? Obviously a real machine shop would have found that problem upon initial machining and assembly.... Tell me if I'm wrong or just plain stupid, but this is the straw that broke the perverbial camels back and might push me out of this hobby... Rant over.

If they have tried to fix it twice, it sounds like he put some time into it. He likely discussed it with his contact for MP - and didnt get anywhere. It is possible that his MP contact is another distributor - therefore adding a layer to wade through.

I know that doesn't help you with your issue - and I am not saying your engine builder shouldn't fix it. My friend has a 392 Hemi built by a well known engine builder in the Cincy area - and his rear main started to leak. The builder told him they would fix it once for free.

I've heard of something with the rear main seals on Hemi and Wedge blocks before. I'm sure someone has come up with a reasonable fix by now. Maybe Superformance has a seal that will hold in the block?

There was someone that made some screwed up seal
retainers that were off center.. but I dont recall
who it was.. if the back of the block is truely off
center he might be able to use one of those screwed
up retainers(if he can find one) or build one

I have a Cummins built 472 crate Hemi engine that I bought in 2005. I have never run it. I know that because of all the issues that these engines had, such as 528 head gaskets on a 472, improperly hardened Comp cams, valve seats falling out of heads etc, that I need to go through a 13k engine completely before I ever run it. My friends 472 Hemi had the rear main seal installed backwards when he fired it up right out of the crate. His second 472 lunched a cam after 6 hours of run time. I plan on a complete rebuild of my crate engine before I run it. I know that the current crate engines are much better quality than the Cummins built engines were, but I just bought a 70 Hemi short block, and I will be building my next Hemi myself from scratch. I would contact Indy Cylinder Head, and ask them if they know of this issue with the world blocks, and if they know of a fix for this. They buy and sell a lot of those blocks. Maybe you have an early world block and this issue may have been corrected.

My block came from one of the last runs in 2012... So I was told? I was also told is was one of the better blocks when I was purchasing the hemi build....

I have an RB world products block that had a rear retainer machined incorrectly off-center .
Replaced it with a Mancini unit. There are quite a few big blocks out there that Drip oil out of there rear main seal .
Jim F

I think we are talking about the actual machined seal bore in the block not the retainer. Mine was off center to the crank centerline. I have a 1990's Hemi block with the same issue, I was able to use a rope seal (the Graph Tite one) , on a non knurled crank, and stop about 99% of the leaking problem.

I know they did have issues with the rear mains being off in the block, not the retainer, the block itself, it was specifically mentioned by my engine guy when I inquired about buying a new block - He said run from any MP block.

To the OP .. I would try Barton, FHO and Bob George too see IF they might have suggestions on a repair.

Barton may have some pull with MP, he was fixing crates that had problems before.(cummins era)

MP had a bad part, but Stanton should have caught it and rejected the block initially. That is where the battle between him and MP will be.

I would be furious also !

The World blocks are good, but have had a few issues. Who supplied the block for the build, you or Stanton? That would determine the warranty issue for me.

I have a World Hemi block and have dealt with the rear main seal leak, the right side water jacket machining issue and now I am dealing with a right side overheat problem. I hope I have a handle on this final issue. We'll see.

Ray Barton probably knows as much about these blocks as anyone. If he would take the time, he would likely be able to tell you what (if anything) you can do to address your problem.

I bought my stroker kit and cam kit from him. So he is my go-to guy on this engine. Frankly, it has been a pain in the a$$. Issues (like the one the OP has) and many others that just shouldn't have come up. So this is probably my last build. I am just sick and tired of doing everything 2 or 3 times due to issues that shouldn't come up. Rant off!

Care to share any photos of the block. I have a bare block I am going to be using for a project and would definitely like to know what Identification marks your block has on it.

Are you running the factory correct PCV valve? Have you checked to see if the crankcase is running in a vacuum at idle and cruise?

How bads the leak? We all want Perfectly sealed engines, but that's just not the case. They all develop leaks. The Builder did seem to try [2 times] and is just not able to get it sealed up. It may be a block issue as others and the builder suggested.

Lots of others have had issues getting that rear seal to not leak at all. Ive had good luck, but am worried every time I put one together. Fortunately, that's not often.

So how bads the leak, gusher, drips, seepage?? Oil fill, pcv valve, and vac hose/lack of vac can all contribute to leaks as well.

Had the same problem with a mp block I got from Barton. Seal groove machined off center. I called Chrysler. They wanted that block back. They covered shipping both ways. This happened about 8 yrs ago. I lucked out on that one. I don't have any casting #s.

My friend went through a similar problem with MP. It turns out a small run or a lot of them left the foundry with some porous problems in certain places within the blocks. This turned out to be not so bad being that the motor is a very mild REAL street build.
I would never purchase a MP piece EVER just on the principle that they (MP) did not want to own up to the issue. It drove the machinist and builder (later to be revealed after clearance) crazy trying to get an answer or a replacement at the very least. I mean, it's all about customer service right? e$pecially with a brand new block ca$ting right? MP did not want anything to do with it. They said, eat it.
At the end of the day, it's almost worth it to seek and purchase a good old casting from the old Chrysler corporation and build it up from there.

My biggest issue with all of this is.... We talked about the rear main issues. I did my homework before spending 20k on an engine... He assured me that if any issues came up they'd be taken care of. Now the story is well most blocks have issues and some leak. He damn sure didn't sing that tune when trying to close me on the deal.... That's where my issue is. Hell I pulled a strong 505/440 out of the car for the hemi, and it didn't leak. I know everyone is trying to be objective, but it's clearly a main seal leak that I can watch run down the rear seal and off the pan area. I'll fix it myself. I've talked to plenty other hemi builders that have talked me off the ledge and offerered their experiences and ideas.

I remember him getting press about being the mp crate builder. This is a good warning to us all he doesnt actually have a contact there if issues come up. Good to know.

I know of a few that get fixed with the rope seal fix....

If you want to get to the root cause of the issue the engine needs to be disassembled (crank & rods out). Then the seal retaining groove must be measured for concentricity to the main bearing bore, also checking the rear seal retainer.

The main bearing bores can be crooked (seen this with the naked eye on a SBC once ) or the seal retaining groove can be machined offset from the centerline of the main bores. Don't know if there is anything to correct the crank being crooked in the block but the seal retaining groove I'd assume could be corrected by machining and making a custom insert for the seal.

If everything is out of spec in that area there is always a rope seal but that is not always rainbows and unicorns either.

The crankshaft also needs to be checked for proper surface finish and size.

Could also be the fact whatever seal was used has inherent issues in quality so the seal itself needs to be inspected as well. Here you better know exactly what your looking for when determining the quality of the seal. Due to the fact a major seal manufacturer has quit production on a 2 piece rear main seals parts suppliers are scrambling for whatever they can put into their kits and keep them going out the door.

Last but not least, installation errors. Common, very common. I don't care if someone has been assembling engines for 30-40 years, they can and I have seen them doing it wrong for 30-40 years yet claim they have never had a problem.

I was recently (10/20) called in to a local business who was in panic mode over a rear main seal leak on a 440 dyno mule. There were 4 different people who put 8 different seals and seal retainers in trying to get a leak to stop but every time it went on the dyno it would sling oil up the walls
I grabbed a seal and some gaskets off my shelf, headed over and tore into it. Installed my seal kit with the stock retainer, ZERO SEALING AIDS, only assembly lube. Put the pan gasket and oil pan on, rolled it over to the dyno, hooked it up, fired it up and made 3 pulls. Wouldn't you know it, DRY AS A BONE!

One of the guys was so skeptical he had to take my picture while harassing me about my soon to be failure
As of 11/17 it's still dry after many dyno beatings testing 2 sets of heads and 4 different cams

ROCK STAR STATUS................