I seen a few threads on this with no clear answer. Has any one on this forum use the Fel-Pro BS-6141 (292 Ford) rear main seal on SBO. I have 403 and would like to run the rubber but the direction and opinions I have read make it unclear if it is a good swap or not. If it is it will save time on tare down and cost for extra timing chain gasket set. I do not see how the Rope seal can be installed with out pulling the crank out of the block. Any body that has done this I would like to know how the Rubber worked out. I don't want to do it again, but If I can get out of a tare down and save time with a better seal this is what I want to do.

 

I did. Worked great.

- Eric

 

Okay, So I have been told to shave all the rubber off the inside that makes contact with the crank. Is there anything else other than the lip going toward the inside of the motor not the flywheel? This should be easy to change with the crank in as well correct? I have already loosened the main caps and raised the crank about a 1/2".

 

Interesting. I would like to know the procedure here too as I am in the process of doing the gaskets on my 350 and would like to use the rubber seals instead of the rope ones. Any and all info appreciated!

Dennis

 

The biggest thing is getting ALL THE ROPE SEAL out, I found using a old speedometer cable worked for me.
Lip on seal ALWAYS GOES IN. not to flywheel.

Johnny

 

"shave all the rubber off the inside that makes contact with the crank."

sounds like removal of the sealing lip to me- a very bad idea.

Surely there is a youtube video of this?

It is super easy.

 

That doesn't make sense. You need contact with the crank to make the seal.



Here is a link to a thread with the only picture I've seen that clearly shows the proper orientation of the seal.




As far as being easy, well... It's a PIA, but you should have no real problem sliding the seal in and around in a circle if you're patient.

- Eric

 

Bill Travatto talks about shaving the excess rubber from the back side of the Ford seal so it sits farther up inside the notch in the block. He also said to put some motor oil on the seal lip and the crank so you don't tear the lip when the crank is rotated on a dry seal.

Jones 1978:
I haven't done this yet but getting educated for my upcoming engine build. Thanks for posting about the Ford seal for Olds small blocks.

 

If memory serves, this is for the 460 Lima seal in a 400/425/455, not the 292 Y-block seal in a 330/350/403.

- Eric

 

Eric:
I watched a You-tube video showing Travatto building a small block Olds motor (I think it was a diesel block). But the diesel blocks have BBO sized main bearing so you're right about the Ford 460 seal for 455 Olds motors. I'm getting ready to build a 375 small block stroker and want to use a better seal than the rope seal that comes in the gasket set. Maybe you don't have to trim the rubber off the backside of the Ford 292 seal to get it to fit in a small block?

 

Exactly.


I try to avoid making blanket pronouncements when I haven't done a particular thing a number of times myself, but I can say that I didn't have to trim mine.

- Eric

 

Trimming the seal as described sounds like a bad idea.
I've installed the Ford small block seal AS-IS in a couple of 330's with no problems.
It went in like it was made for the Olds engine.
One thing I'd read to do, that I didn't do, but it makes sense,
is the grooved, knurled surface on the crank
where the seal makes contact should be smoothed with emery cloth.
Apparently the knurled surface somehow seated the rope-type seal, but,
there is concern about the knurl wearing the Ford seal prematurely which makes sense.

Also, you probably already know this but, instead of installing the seal halves with the ends
flush with the mating surfaces on the block and bearing cap, leave one end of each half
sticking up so that the ends of the seal halves meet in the block and cap rather than at the mating surface.
Also, use a small dab of silicone on the ends of the seal halves to seal the ends together.

 

Make sure the crankshaft is polished as much as possible in the seal contact area

 

... But, there are some who have not done this (such as yours truly), who have had no problems.

I don't claim to have the "right" answer, but I have not (personally) seen any documentation of anyone who did not smooth the serrated surface and subsequently had a sealing problem.

- Eric

 

I didnt smooth out my crankshaft when I installed the neoprene seal that I bought from Mondello's. No oil leaks on my garage floor.

 

You can of course just install the crank without it polished and it will probably be fine...if you you make sure its smooth as a babys butt you will be certain it will be fine...provided its round and seal is installed correctly

 

Not arguing, just providing a data point.

- Eric

 

Ok so I didn't get any straight answers out of any reads or videos, or people so here is what I have done. This is with the motor out of the car. I removed all the main caps and pried up on the rear of the crank where the flywheel goes. ( I did not remove the front of the motor so the crank couldn't be removed.) Remove the Rope seal with wire or something flexible and stiff. Now To install the FEL-PRO BS-6141 Take it out of the package and trim the outer spine of the seal ( MOTOR SIDE NOT CRANK SIDE) use a pry bar to lift the crank out of the motor as far as you can and after coating the seal with oil and facing the lip of the gasket toward the front of the motor work it in to the block under the crank. They say to off set the seal 3/8" on the block and cap... I have it installed and the crank moves free. Re-install the Main caps and work front to back to set crank back in block. Torque to spec and reassemble motor. Hope this clears up the unanswered questions on using the Ford 292 rubber seal to replace the rope seal.

 

There were unanswered questions?

- Eric

 

Did you use some rtv?

 

I did use Black RVT on the ends of the main seal where they come together. I did not use any on the inside of the motor or main cap. As far as the unanswered questions, I didn't check the post before I wrote my input. I think this will benefit a lot of people who have been looking for the whole answer and not just what seal to use and that it worked well. I could not install the seal with the crank in. The rubber spline was catching on the block. after shaving the spine off it still had to be worked into the block. I believe that it may not have to be trimmed if the crank is out of the block. I will see how that works on a 455 I will be building in the future. Thanks for all the input.

 

I installed one with the engine out and the crank and rods in place, with the main caps loosened, with the crank less than a quarter inch raised, by pulling the rope seal out in pieces with a pair of very long needlenose pliers, lubing the channel, and simply feeding the seal into the channel by firmly rotating it into position, without trimming or modifying it in any way.

Once the seal seemed to be in position, square with the machined surface of the block, I pressed on both edges to be sure it was seated, cleaned the end faces well, then pushed it a few degrees to get one end to poke up, as recommended, applied silicone sealant, and reassembled.

As with my comment above, I'm not saying anything is right or wrong, but that was my experience.

- Eric

 

I tried to install mine without trimming and it hung up on the block. I tend to rush things though. I don't see that 1/32 of lip being an issue with clearance. I believe it would work with it attached as well. I would do it again. I tend to ask a lot of questions until I am comfortable doing something. If it does not seal it is a major job to redo. I would hate to think I have to pull the whole motor again to install a 15.00 seal. I think I would douse it with gas and torch it if that were the case.....

 

So does anyone have a diffident answer to if the ford 292 rear seal works on the olds 350??? Someone who has actually installed and ran their motor for a good amount of time???? The rope seal looks like it will fail in a matter of time.

 

I've had a few Oldsmobiles with their original rope seal. Most didn't leak until well after the time for rebuilding. Even then the leak was a few drops a month.

I rebuilt my 455 22 years ago and used a rope seal; no leakage yet.

 

I've used the 292 seal in an Olds 350 with zero issues. I didn't have to cut anything. I've used the Ford 460 seal in every BBO I've ever built, also with zero issues.

 

I've done it on a 350 and 455 both worked well I ordered both from summit. As far as the rope yes they can be replaced without pulling the crankshaft they used to make a tool for doing it it was like a wire with a handle on one end and a clamp of sort on the other. It came with an aluminum punch for packing the rope once you get it in.

 

I have used the Ford 292 and the AMC 252 seal with the ears cut off. The AMC seal is a tighter fit, nothing cut off other than the ears on the AMC seal.

 

I will be doing this soon with a BBO, was told the worst part is removing old rope seal, there are tools for the rope seal work in industry, called packing
The BBO seal has a tab that must be cut off, other than that, was told it was an easy task.

packing removal tools | McMaster-Carr

 

There is no tab to cut off.

 

Joe, maybe I have the wrong one? ID is correct at 3.125, I'll know when I get the cap off. Maybe tab is for Ford applications? idk.

 

Ford 429/460 is correct. I've used that FelPro seal before and have never seen those tabs.

 

It's probably for molding, either for the gating or a cold slug well, common in injection molding to allow gate flaws or to get gas burning out in the process, sacrificial part of seal. (I'm a moldmaker for 45 years!)

 

This is a good thread.

Just to clarify on shaving of the 460 seal for the BBO, Bill says to install it, spin the crank to see resistance level and then shave backside if needed.
I have installed two, one was tight and one was good as is.

 

I had some luck last night, was able to pull old rope out once I grabbed ahold of it, rotated the crank as I was pulling old seal rotated right out of block side, installing new Ford seal and appears I can do the same thing by rotating the crank as I feed seal into block, will require 3 hands though 2 to feed it in carefully 1 to turn crank, all rod caps are still tight less main end cap obviously, old engine just doing re-seal and valve job, don't want to do full tear down.

 

I would leave the seal OD alone, a bit of crush will help seal the OD, in my case I don't believe I can get any sealer on the OD as I feed it in, using some lube to assist it's insertion , any sealer would get wiped off as I roll it in.

 

The Felpro 2948 is the high performance/race seal designed for dry sump hi vacuum crankcase applications. It’s made from Flourolastomer not Viton like the stock type one.
the 2948 ones have the tab you have to cut. the tab is just an identifier for the mold and what material to use in it for the race version…and then after to identify it against the stock one

the BS40032 is the stock Felpro seal

 

heres my dads old sneaky pete.