Rear Main Seal Offset or Not and rtv usage

[snowboundrmk]

For a 2 piece rear main seal should it be installed flush with the block surface or offset like this picture?

Also should rtv be applied to the seal ends where they meet, or anywhere?

 

[413]

I don't offset the ends.
No sealer anywhere on the seal halves.

That looks like some new trick seal, what do the instructions say to do?

 

[Inertia]

A lotta rear mains come with the "ears" attached to the seal, so you can't offset the ends .
Having said that, most other makes do not.
I have used both styles, - both ways, don't remember any leaks.
I never mess with or add goop to the ends, or any place else.

Good Luck

 

[413]

What engine is in the picture, why a thrust bearing at the rear?

 

[snowboundrmk]

I don't offset the ends.
No sealer anywhere on the seal halves.

That looks like some new trick seal, what do the instructions say to do?

The photo isn’t mine. I was using it for reference. It is from felpro. How to Install a Rear Main Seal

 

[snowboundrmk]

What engine is in the picture, why a thrust bearing at the rear?

Not sure. Just using it as a reference. How to Install a Rear Main Seal

 

[Murray]

As like rope seals, a small amount of seal above the block allows for crush/tension upon installation. I use a very small film of RTV on rubber seal ends.

 

[Newbomb Turk]

If the seal has wigs on it, you leave that half alone.

You put the other half in the block and you determine how far the seal is proud of the block.

You only want to .010-.015 proud. If it’s more than that you need to cut the seal down until you get there.

I do it with a belt sander but you need to go SLOW and sneak up on it or you’ll Jack it up. If I have a cap cutter I use that.

You never offset a seal like many do. The seal is similar to a bearing in that it has crush built into it so that when the two halves are put together they had some load on them.

If you offset the seal you change that. And if the seal has too much rush it will go out of round and leak like a sieve.

 

[413]

The factory never offset the rear main seal and they produced millions of engines that made it through warranty without leaking.

 

[supertruck]

I use a small amount of Honda Bond where the two halves meet.

 

[CRUZE 418]

After 4 tries on a small block, I cut the wings off and clocked the rear main seal. Finally, no more leaky rear main. Did the same on my Hemi, with a little anaerobic silicone on the mating ends. Have not run the Hemi yet, so I don't know. Just saying, if you develop a leak from the common practice, sometimes you have to try something else. Not saying to do what I did , the other way for whatever reason, just didn't work for me.

 

[dogbreath]

The factory never offset the rear seal because the vast majority of pre magnum small blocks used a rope seal.

 

[MOPAROFFICIAL]

I offset the seals.

I've run both ways.. but st some point I decided offset was the method for me.
I also cut the wings off if that type of seal is used.
Dot of sealer on the ends and a thin line across the cap/block saddle mating surface.

Only leaks i ever have once in a while are that damn rear pan seal.. I swear they don't make one thats a perfect fit.. 360 is worse with is thinner style seal thats too long in most cases... but street driven anything that sees 6800-7200 rpm shifts is prone to some seepage in my experience at least.

 

[1MeanA]

Offset slightly with a dab of sealant. I think blue seals are viton.

 

[Bewy]

I would use a little bit of offset. Many of these engines originally used rope seals; less machining accuracy was needed with rope. So offsetting slightly & a dab of silicon will ensure a good seal.

 

[RustyRatRod]

I've never offset and I've always used a dab of RTV on the ends. If you're that worried, just use one of those new one piece seals.

 

[junkyardhero]

If you're that worried, just use one of those new one piece seals.

who makes that?

 

[RustyRatRod]

who makes that?

Fast Fish used to have um but I don't see um now. They still show the one piece for the big block/slant 6 and many others. Maybe they just don't have them on their site. They used to.

 

[junkyardhero]

Fast Fish used to have um but I don't see um now. They still show the one piece for the big block/slant 6 and many others. Maybe they just don't have them on their site. They used to.

oh you meant a split seal. when you said one piece i thought like sbc or modern stuff and was all how in da fuq did i miss somebody coming out with that?

 

[Cal Tonsley]

Most recently I have offset the seal with some anaerobic sealer on the cap and a small dab on the seal ends.

 

[RustyRatRod]

oh you meant a split seal. when you said one piece i thought like sbc or modern stuff and was all how in da fuq did i miss somebody coming out with that?

No dummy. How da hell you gonna get THAT over the crank flange? A split seal is still one piece. Although Tim Meyer does offer a one piece seal with no split for the 335 Cleveland engines. I have one in my 400. Narry a drop. The crank flange on the Fords are made so you can install one on buildup.

 

[junkyardhero]

No dummy. How da hell you gonna get THAT over the crank flange? A split seal is still one piece. Although Tim Meyer does offer a one piece seal with no split for the 335 Cleveland engines. I have one in my 400. Narry a drop. The crank flange on the Fords are made so you can install one on buildup.

look sizzle chest, i don't know what kinda ferd junk might'en be rolling around in that cavern between your ears and ya could be conflating it with mopar!

 

[Dave999]

I used a cut down and recurved 1 piece Pontiac seal from BOP Engineering.. fits where a 318 seal fits once you have cut out an appropriate sized chunk of it. need to get it the right way so the pattern on its lip drives oil back in to motor

see here BOP Engineering Engine Accessories half way down 3 inch and 3.5 inch too BIG...

I asked him on a number of occasions to get mopar sized one done...he said no.


below
the approach to getting it round and getting it the right size. Note how it ends are puckered up in the middle picture. needed a bit more off.
Do not take its orientation in the housing as the right way it was in and out about 5 times as I removed a little at a time.

cleaned out housing
bead of anerobic
well glued..

Thought i was a genius when done, then discovered mopar versions DOH! But never in stock ... and only for big block, i needed 318 size

The BOP Engineering guy has them just in huge pontiac sizes so i just chose the closest and cut it
(don't worry about engine. not 318 its 265)

 

[rmchrgr]

Offset dude, all the way. Only has to be enough to ensure the seal parting line is not parallel to the block and rear main cap parting line.

Superformance #9340 Rear Main Seal

The factory never offset the rear main seal and they produced millions of engines that made it through warranty without leaking.

Warranty period is generally about 1/3 of the intended service life of factory parts so that's not really saying much.

Rear main leaks usually happen because of A) improper installation, B) imperfect mating surface or C) letting the car sit for long periods of time. Sitting is especially problematic with a rope seal because they wick oil over time and swell.

 

[RustyRatRod]

look sizzle chest, i don't know what kinda ferd junk might'en be rolling around in that cavern between your ears and ya could be conflating it with mopar!

Looky here you city slicker, don'tchyoo be talking down to me like that!