New ONE PIECE Rear Main Seals

[Schober Motorsports]

Hey guys,

Just came across these on my travels... Apparently its a one piece rear main seal for big block mopars. Has anyone seen these or used them yet? Curious to see what you guys think. On a side note, from what we have on the market right now, what is the best route to go to combat the leaky rear main seal? I just fired up my engine for the first time this year and I got the constant drip coming out every 2-3 seconds. Any ideas?

Link: http://www.fastfishautoparts.com/Performance-Engine-Seals.html

 

[Dennis H]

An experienced Mopar guru is needed to properly install this seal. On a Wed. At 75 degrees. At sea level. At three in the afternoon. Pacific time. Saw this in MCG magazine.

 

[snakeoil24]

Thisis a great idea, I think it is a cummings double lip seal for Diesel Engines. If you have one or bought it let me know i will track it down. This should sell for maybe 22.00 to 25.00 max. I need you to mic it and look inside the seal for the production number. paying 79.00 is expensive..

 

[themechanic]

That woulod be hard to install in-car.

 

[69Bee]

No disrespect Snakeoil, but I think this seal solution is snakeoil. They want you to simply "cut" the seal so you can put it over the crank. You can't slice a seal with metal inside for rigidity without making the diameter smaller. I do not see this working out too well, and it is the latest and greatest solution with no longevity and reliability testing. I have been building motors for a long time, and I can not remember when I had a rear main seal leak on me. If you install the seal properly, and are careful, you won't have a leak. I don't feel it will work well.

 

[69roadr]

wonder why it's not cut from the factory? they want you to "simply cut it".
69Bee, have you ever replaced a rear main seal with engine in the car? if so, please tell how it's done. i have a leaky rear seal as well with less than 5000 miles on the engine.

 

[themechanic]

There are a few how-tos on this topic. Basically, just raise the car on stands, drop the oil pan (possibly the center link, too), loosens the remove the rear main cap, punch the upper half of the seal out, loosen slightly the main cap bolts, tap the new seal half in 1/8 off center, silicone on the ends, install main seal and cap, torque main cap bolts, let dry 24 hours.

This is from memory. So, I may have missed something but you get the drift.

I don't know whether this can be done in other models. I can't speak for any Mopar but mine.

 

[A383Wing]

how does one get it over the crank flange?

 

[Garys1969RR]

My rear main seal hasn't leaked in 4 years. Once I installed the neoprene seal, I cleaned the edge of the seal cap with brake cleaner. Then ran a nice wide bead of oil resistant black silicone along the edge where it meets the block. I think most leaks come from the weird "side seals", that fit between the seal cap and the block. This way you have 2 blocks to the oil getting past there. The side seals are supposed to expand when oil hits them, and seal to the block. The round neoprene seal is pretty straight forward, and probably not where the oil leaks from. I put mine in with the parting line even with the block. I dont see how a one piece seal could be installed on there. Besides, that is not the weak spot in my opinion. Its the side seals.

 

[Bb70charger500]

You just snake the top half in make shure it's faceing the correct way . And just slide it in place very easy you don't have to remove the crank or anything just the rear cap that covers the seals

 

[Meep-Meep]

no disrespect snakeoil, but i think this seal solution is snakeoil. They want you to simply "cut" the seal so you can put it over the crank. You can't slice a seal with metal inside for rigidity without making the diameter smaller. I do not see this working out too well, and it is the latest and greatest solution with no longevity and reliability testing. I have been building motors for a long time, and i can not remember when i had a rear main seal leak on me. If you install the seal properly, and are careful, you won't have a leak. I don't feel it will work well.

exactly ^^^^^^^

 

[69Bee]

wonder why it's not cut from the factory? they want you to "simply cut it".
69Bee, have you ever replaced a rear main seal with engine in the car? if so, please tell how it's done. i have a leaky rear seal as well with less than 5000 miles on the engine.

All rear main sets (Fel-Pro at least), come with a white plastic strip. You place the small end between the seal and block at the main parting line. This will prevent the block from shaving the back side of the seal when you rotate it in. As themechanic suggests, you use a punch or screwdriver (CAREFULLY), and push the seal out. Using the method I described above, you rotate the lubricated seal back in. Put the lower seal in the seal retainer as normal, and install it.

As Garys1969RR postulates, I agree that the leaks emanate from the improper installation of the side seals. Fel-Pro doesn't include them in their set for some reason, but rather RTV and 2 pipe cleaners. I think they removed them because too many people didn't know that you had to soak them in mineral spirits so that they would swell after installing them. If you installed them dry, they will leak. Properly used, you work quite well. I throw away the pipe cleaners, and either just fill the void with RTV, or get the Mopar Performance Rear Main kit P4271691:

http://www.rosevillemoparts.com/pro...-and-big-block/cPath/166_169/products_id/4290

The side seal shown are the old style, but the ones included are rubber. I still used RTV to ensure a complete seal.

- - - Updated - - -

how does one get it over the crank flange?

They want you to cut the seal, twist it open, and spiral it onto the crank. Not only does that have an effect on the steel in the seal, but you have to remove the crank to install it. If a problem does crop up, you can completely destroy it getting it out, and put the PROPER seal back in.

 

[Dennis H]

This thread confirms that there is no replacement for experience. Mine doesn't leak either because a Mopar person installed it. No way this should be so gd complicated. The other one advertised a lot (unnamed) has leaked for many too. When called on the phone, the people who sell this stuff don't know wtf they are talking about.

 

[kiwigtx]

I don't believe this one-piece seal to be any better than the original two-piece deal. Why have a seal that has to be cut in the first place. It would be easier to manufacture the seal as pre-cut to avoid further damage. Surely this seal as shown above is a gimmick....and an expensive one at that. Where abouts do you 'clock' the cut that you are supposed to make prior to installation - top. bottom, 45 degrees??? Sounds like a load of BS to me. How is one cut in the seal any better than the original "two cuts"
And I would think the amount of stretching involved in avoiding the cut to get this seal over the crank flange, would make it permanently too large, then it would leak anyway. :eusa_doh:

 

[lewtot184]

i've never had a factory style seal leak. how do you make them leak?

 

[1966satellite]

My rear main seal hasn't leaked in 4 years. Once I installed the neoprene seal, I cleaned the edge of the seal cap with brake cleaner. Then ran a nice wide bead of oil resistant black silicone along the edge where it meets the block. I think most leaks come from the weird "side seals", that fit between the seal cap and the block. This way you have 2 blocks to the oil getting past there. The side seals are supposed to expand when oil hits them, and seal to the block. The round neoprene seal is pretty straight forward, and probably not where the oil leaks from. I put mine in with the parting line even with the block. I dont see how a one piece seal could be installed on there. Besides, that is not the weak spot in my opinion. Its the side seals.

I agree with Gary!

 

[Schober Motorsports]

Thanks for the feedback guys, Just something I saw that I wanted to pass along. Currently I have the 440source aluminum main seal cap... Maybe a good idea to go back to stock? OR Give those orange side strips a try again with soaking them in mineral spirits to put em in?

 

[fastfishauto]

A lot of effort, time, and money went into the design, tooling, and production of these one piece seals. Many have been sold, and used especially in drag race engines. They are not snake oil, out of a Cummings, and they do not have metal in them. From a materials, dimensions, and sealing ability, it is a better choice than the two piece. If you have questions please ask the people who designed it.

Thanks Jeff www.fastfishautoparts.com

 

[themechanic]

A lot of effort, time, and money went into the design, tooling, and production of these one piece seals. Many have been sold, and used especially in drag race engines. They are not snake oil, out of a Cummings, and they do not have metal in them. From a materials, dimensions, and sealing ability, it is a better choice than the two piece. If you have questions please ask the people who designed it.

Thanks Jeff www.fastfishautoparts.com

Welcome to FBBO. Now, since you're here, how about answering the questions above to clear the air?

Thanks

 

[WP29440SE]

im just not seeing the benefit , you still have to cut the thing in half.. the last one I installed about 2 years ago has seen hundreds of leak free miles. not a single drop. the 2 piece was a good design back then , and when done correctly, it will last a long , long time. im sure if there had been an issue with it, Chrysler would have fixed it before letting millions of big blocks out of the door.