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351 Rear Main Seal???

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Bruno2

351 Rear Main Seal???

Is there another option for the rear main seal besides the rope style? Does the application differ as far as can I use a different style on my motor or am I locked into using the rope seal?

I thought I had read somewhere that there was a two piece press in seal? If so does it fit all 351W's?

Whitey: 1996 F 250 XL CCLB 4X4 7.3 DI ZF5 (The Work Horse) Lots of power mods
Whitey Jr: AKA Jr 1982 F 150 CCLB 4X4 351W C6 (Jr Work Horse) respectable power, but not over the top
The Bronco: 1987 Bronco XLT 351W C6 (needs work) Lots of off road mods and plenty of power mods
The Dodge: 2006 Ram 2500 CCSB 4X4 5.9 HO Cummins (The reliable ride that cant keep an AC in itself) (5th AC go around almost complete)

Gary Lewis

Re: 351 Rear Main Seal???

Administrator

There's a rubber style, but it is also a two-piece seal. Fits just like the rope seal, but you have to remove the pin before using it.

The block has to be machined for a one-piece seal. I'm not sure if the 351W ever had that from the factory.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Whisler

Re: 351 Rear Main Seal???

351W built after 7/11/83 used a one piece press-in seal.

God Bless
Whisler

Frankenstein: 1989 F250 4X4, C-6, Hurst Pro-Matic 2 shifter, carbed '84 351W, Edelbrock manifold, Edlbrock AVS, DS2 ignition, 3G alternator, JBA shorty headers, no cats, dual exhaust with H pipe.

Gary Lewis

Re: 351 Rear Main Seal???

Administrator

Give that man an award!

Gary, AKA "Gary fellow": Profile

PetesPonies

Re: 351 Rear Main Seal???

Bruno, what year engine do you have?

Pete's Ponies
Mustang RUSToration & Performance

1982 F100 Flareside
1983 Bronco

Bruno2

Re: 351 Rear Main Seal???

Gary, what year truck did that block come out of?

Gary Lewis

Re: 351 Rear Main Seal???

Administrator

I don't remember for sure. It might have been from Brownie, the 1982. Or it might have been from the 1985 I parted out. I don't remember.

Post a pic of the rear main location?

Gary, AKA "Gary fellow": Profile

Gary Lewis

Re: 351 Rear Main Seal???

Administrator

I believe this is saying that the block will have "6015" cast in it and that you can't use that to figure out what it is. But, just in case, here's what the catalog says for 351W's:

Gary, AKA "Gary fellow": Profile

Bruno2

Re: 351 Rear Main Seal???

I will get a pic of the casting numbers as well as the main cap on the rear and post it.

Bruno2

Re: 351 Rear Main Seal???

Bruno2

Re: 351 Rear Main Seal???

Bruno2

Re: 351 Rear Main Seal???

Gary Lewis

Re: 351 Rear Main Seal???

Administrator

In reply to this post by Bruno2

Brandon - Glad you figured out how to post the pics.

On a bigger screen than my phone, I think that is a standard 2-piece seal. But, I wouldn't bet on it. Hopefully others can say definitively. The reason I say that is because a one-piece has to have a recess to be pressed into, and I don't see a recess in your pic. But, perhaps it is there and I can't tell?

On the cast-in numbers, the D4AE says the block was engineered in '74. And the fact that the new seal came into being in '83 might suggest that there could be an E3AE block. However, the change on the seal probably was done via just different machining rather than casting.

As for the AA 4, I dunno.

Then there's the casting date code of "5K6". Ford used a year/month/day sequence, so that means the block was cast on November 6th of X5, meaning either '75 or '85. As said, that engine either came out of an '82 or an '85, but neither would have had a block cast in November of '85 as that would be for 1986 model vehicles.

So, I don't know what to tell you. But take a look at this pic for what I mean about "recess" for the seal to go into:

Gary, AKA "Gary fellow": Profile

PetesPonies

Re: 351 Rear Main Seal???

Looks to me like 2 piece seal as well.

Pete's Ponies
Mustang RUSToration & Performance

1982 F100 Flareside
1983 Bronco

Bruno2

Re: 351 Rear Main Seal???

What do I need to know about installing one of these two piece seals correctly?

Gary Lewis

Re: 351 Rear Main Seal???

Administrator

I'll scan the instructions from the shop manual after church and post them - assuming someone else doesn't beat me to it.

Gary, AKA "Gary fellow": Profile

Gary Lewis

Re: 351 Rear Main Seal???

Administrator

Brandon - We now have a new page: Engines/Engine Building Basics. And at present it has one tab: Rear Main Seals.

Check it out.

Gary, AKA "Gary fellow": Profile

PetesPonies

Re: 351 Rear Main Seal???

This post was updated on .

In reply to this post by Bruno2

Make sure you have it turned the right way. The lip faces into the engine. When installing the piece in the block, don't set it so it is flush with the block on both ends. Have one side sticking up about 3/8" Put a very small amount of RTV on both ends, so when the other side of the seals butts up, the RTV will help seal the two halves together. When putting the seal in the rear cap, offset it so it matches the piece in the block. Wipe some oil on the lip so the crank isn't turning dry against it, at start up. That's it.

Pete's Ponies
Mustang RUSToration & Performance

1982 F100 Flareside
1983 Bronco

Bruno2

Re: 351 Rear Main Seal???

In reply to this post by Gary Lewis

I got this from another forum:

https://youtu.be/824nXveTQs0

This explains that the seal is designed to expand when soaked in oil. So the assembly is supposed to be as quick as possible after seal is removed from oil. So all of the bearings and caps need to be ready to go assembly and torque.

Gary Lewis

Re: 351 Rear Main Seal???

Administrator

Brandon - Why use a procedure other than that from the official Ford shop manual? Ford doesn't say to soak it in oil. But they do say to put RTV on it, which isn't going to work at all with oil there. In fact, they say "Do not allow oil to get on the sealer area."

I would not use that process, but would follow the Ford one, right out of the official publication, to the letter.

Gary, AKA "Gary fellow": Profile