VinMichael

I did a search and found some info on 2 piece rear main seals: Ford 292 seal (BS6141) or a 258 Jeep seal works on the 2.5" SBO mains.

Now, I'm wondering if it's OK to go ahead and install these as-is, or if they need to be modified at all?

Saw a post saying something about "trimming the ears" on the seal. I have no idea what that means.

Please chime in with insights and experiences if you have any. Thanks

MDchanic

I believe that the Jeep seal has ears that follow along where the oil pan gasket would be.

The F_rd seal does not - it is a standard seal, but it does come with two straight pieces that you throw away.

The direction that the seal has to face seems obvious, but then again it can seem less than obvious.
It has to go like this:

The site that this picture came from is the only site I found with pictures and information about installing this particular seal.

When installing the 460 seal in a big block, you have to shave the rubber off the back, but NOT with this seal in a smallblock (I hope...).

If you are replacing a rope seal and still have the crank in the block, it will be a little tricky, as you can only lift the crank about ⅛" off the bearings with the conrods still attached (if the engine is in the car and you are on your back, the crank will "lift" itself for you quite readily, but only this far [if you're lucky ]).

I was able to remove the rope seal with a pair of long needlenose pliers, after removing a whole bunch of rope shreds first - just keep reaching in there and grabbing stuff until it comes along. There are special tools for this, but, hey, who needs stinking special tools, right?

After some cleaning and some lubrication, I was able to push the neoprene seal into the groove without any drama.

The seal should be installed with the mating edges of the two halves offset about ⅜" from the parting surfaces of the bearing cap, and a tiny bit of silicone sealant should be placed on the two mating edges of the seal halves (unlike the way that the rope seal was installed).

Also, there has been discussion here about whether the serrations in the crank fall under the seal lip or not, and whether they should be removed.
1. Yes, on the smallblock, they DO fall under the sealing surface.
2. I did not try to machine or polish the crank - I installed the neoprene seal right over them (as others have done), and I have had no leaks yet (in 500 miles... Knock wood).

Good luck!

- Eric

VinMichael

Very cool MD, that seems like all the info that's necessary. Going to order a F_rd seal. The engine is out of the car btw, luckily. Oh, and I've installed new rear main seals over worn grooves in the crank too and everything turned out fine . Thanks a lot man

joesw31

Victor makes the small block olds rear main seal that takes no trimming.

The part number you want is JV748

MDchanic

That is the exact same seal as the BS6141 F_rd Y-block seal we've been talking about, only by Victor Reinz instead of FelPro.

- Eric

VinMichael

The JV748 seems to be a few bucks less than the Fel Pro. That's always nice, great suggestion.

VinMichael

Holy smoke, just saw the serrarions MD was talking about. I was thinking of something completely different, oops.

Anyway, I suppose that I'll be placing the seal directly over them. Was not expecting to see 45 degree notches on the sealing surface, though.

coppercutlass

Im just curious whats the pro's and cons with the rope vs. the rubber seal ? I have ran the rope seals with no issues and i just install them dry. I ask this becasue my new budget nitrous build short block had the rubber seal but i have a few rope seals. not that a few bucks are a deal breaker but i have never used a rubber seal before.

MDchanic

In theory, the rubber seals seal better and last longer.

In theory.

Rope seals are 150 year old technology. Rubber seals are 60 year old technology.
All modern cars use rubber seals because they work better end cause fewer service problems.

- Eric

VinMichael

I heard that the crank needs to be lifted up to replace with a rope seal. Rubber halves don't have that issue...that I know of. The rubber one I replaced on a 318 slid in no problem however the slot for the Olds seal looked awful tight, though.

oddball

Those are required for the rope seal to work. Allows the rope to stay wet, but pulls oil away from it. Rubber lip seals do not need that, and if the serrations have any high points, will actually tear up the seal. You can just give that area a good polish to knock down any edges and be good.

MDchanic

But not too much of a polish, because if you take it down too far, you'll lose some of the rubber seal's pressure against the crank.

- Eric

VinMichael

I installed it yesterday and just ended up putting the seal on the crank as-is. Ran a fingernail over them and they seemed rather dull and harmless.

Macadoo

Hey Michael, just wondering of the new seal still seals. I'll be doing the engine-out, crank-in rear main seal replacement soon. Any tips?
I know this is an old thread but thought I'd ask anyway.

olds 307 and 403

The old rope seal is a bitch to get out. It is much easier if you pull the crank. I used a stiff but bendable rod to push the rope out. Then pull chunks out with pliers. I used the AMC seal, supposedly a tighter fit and cheaper. Lube the seal to slide in the passage, it is a tight fit. Make sure to use a dab of RTV where the halves join. I also off set so the halves meet in the block, not sure it helps. The 403 I did had no leakage, the 350 has minor seepage. A lot easier to change, if you have issues.

VinMichael

I got the seal in but I haven't fired up the engine yet to check for leaks. The engine's back in the car; just need to hook up the electrical. I didn't have any issues pulling out the rope seal. Just snipped it and pulled it out cleanly. No problems. The 2 piece slid in great. I'm expecting it to seal up nicely.

As far as tips, all I can say is I followed the directions on the box. I didn't stagger the seal like some insist on doing, but that's just my opinion. I installed it with some motor oil for lubricant, then clean the ends of the seal with solvent and applied some RTV to each end. After that I put on the main cap and torqued.

Macadoo

Well it'll be a while before I get that far. Michael, can you post back with the results after running it a bit? Which seal did you end up using, the Ferd or the Victor?