Rear main seal and a tube of toothpaste?

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dibbons

dibbons

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rear main seal package.JPG
(#P91055-1)

I have two identical Felpro 273/318 rear main seals both still in sealed packages. One of them has a little template or something in the shape of a mini-tube of toothpaste (see left upper corner of foto). The second package only has the two piece seal.
 
At least you will have clean teeth when you install the seal...
 
OK, like I have said on some other threads, let me repeat how my nephew replaced the rear main seal (and oil pan gasket) without raising the motor in my '72 Bbody, but now I have an oil leak in that same area.

Does anyone have a foto/video of where the RTV should be placed when changing the rear main seal. The instructions on the package seem to be rather vague: "Apply RTV sealer to the outside edges of the cap recess in the block". The cap recess is obviously in the cap, not in the block. That's why the wording is confusing to me. Actually, I need the clarification for my Spanish speaking nephew, who did the work and he doesn't speak English. If I had something to show him, it would be easier to explain. If he did use RTV somewhere, it's going to be difficult to explain to me exactly where because of our language conflicts. Thank you. P.S. I pulled the motor out today so we can get a real good look at things.
 
I'm bumping an old thread here. Confusing issue with 70 340 rear main seal. See pics. I haven't nipped the ends off the one 1/2 yet. I want to double check as the seal(National #5414) stamped on the seal itself and on pkg is felpro P91055-1. Seal was almost $60! Doesn' look like it will seal/squeeze onto much of the crank. Any online specs I've found give it an od of 5.627". No way in hell it is. But at that spec it wouldn't fit in main cap anyway.
Ideas suggestions? Forged crank ground .020"/.020"

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Like this, a thin coat on each side and I like to offset the seal ends so they don't line exactly up with there the cap and block come together.
Of course with the seal that has the wings on them you can't do it that way.

20171206_132552.jpg
 
that spoon looks like a ways cleaner, run it in the groove to see if there is any crap stuck in there>? How would you use it to roll the seal in.?

IIRC the cap recess in the block is the edge you see outboard of the bolt holes. run a thin bead there.
 
Well maybe I'm over thinking this **** again! I temporarily installed the seal 1/2 without tabs in the block and then placed crank in. There appears to be some "squish" on the seal which looks good?
The other seal 1/2 with tabs I just laid in the cap where it should go. Altho I will admit i thought the tabbed 1/2 got trimmed and installed in block?
To me it looks like that if installed as intended you can' offset the seal? Or if you trim tabs and install in cap then do you fill/seal these new "gaps" with rtv?
Thanks guys.
GeorgeH said:
That's a spoon so you can roll the seal in without cutting the backside if that's what's your asking??
Click to expand...

TrailBeast said:
Like this, a thin coat on each side and I like to offset the seal ends so they don't line exactly up with there the cap and block come together.
Of course with the seal that has the wings on them you can't do it that way.

View attachment 1715118482
Click to expand...

pishta said:
that spoon looks like a ways cleaner, run it in the groove to see if there is any crap stuck in there>? How would you use it to roll the seal in.?

IIRC the cap recess in the block is the edge you see outboard of the bolt holes. run a thin bead there.
Click to expand...

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Thanks.pishta. a couple more questions.
If i use this seal as is, it can't be offset?
If I do trim tabs off and install in cap, do I fill new gaps with rtv?
Is there a one piece seal available? Makes sense to me when crank and cap are removed from engine anyway?

Thanks
Steve
pishta said:
that looks correct.
Click to expand...
 
Last edited:
On the rear main seal 1/2 going into the cap....how much of the tabs do i trim back?
I've taken a bit off each end. Wondering if u have to trim back to where the end of small screwdriver is pointing? See the profile pic...will that compress completely?
Thanks!

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4spdragtop said:
On the rear main seal 1/2 going into the cap....how much of the tabs do i trim back?
I've taken a bit off each end. Wondering if u have to trim back to where the end of small screwdriver is pointing? See the profile pic...will that compress completely?
Thanks!
Click to expand...

Yes, it completely compresses and I like to smear a thin film of the RTV across the cap surface where that those ends will contact. (barely enough to see the color of the RTV)
Razor blade them off here, so they reach the outer edge of the recess in the block where the cap goes.
FYI, you can't offset that type of seal.
Only the type that both halves are the same and don't have the little arms that sit in those indents.

Conrats man, you got everything in the right way first try.

20171206_183301.jpg
 
Yeah I'll give a final trim on the ends. I'm surprised it'll squeeze down that much.
Yes on the rtv as well. Back in a while with good display hopefully.
Thanks TB.
TrailBeast said:
Yes, it completely compresses and I like to smear a thin film of the RTV across the cap surface where that those ends will contact. (barely enough to see the color of the RTV)
Razor blade them off here, so they reach the outer edge of the recess in the block where the cap goes.
FYI, you can't offset that type of seal.
Only the type that both halves are the same and don't have the little arms that sit in those indents.

Conrats man, you got everything in the right way first try.

View attachment 1715118559
Click to expand...
 
put a Timkin in 90 degrees out, would almost become a 1 piece but I dont see any 1 piece 360 crank seals that can stretch around the crank flange! :lol:
TMK-5106_ml.jpg
 
When using the rubber seal as opposed to the old rope style seal, I understood the serrations on the crank have to be removed/smoothed?

20171206_151027-jpg.jpg
 
That may have been true for a reverse rotation engine, but I have successfully used the lip seal on many both rotation engines with no polishing, andno issues.. No trimming is nec. for anything but the old rope seal.. cheers
 
I read that somewhere as well Dar. Altho I didn't ask my machinist (who I bought shortblock from). I figured I would go with split lip seal. Machinist polished crank so I figure if it' a "must do", he would have done it.
Thanks inertia, good to know it' been done successfully before.
65Val said:
When using the rubber seal as opposed to the old rope style seal, I understood the serrations on the crank have to be removed/smoothed?

View attachment 1715118817
Click to expand...

inertia said:
That may have been true for a reverse rotation engine, but I have successfully used the lip seal on many both rotation engines with no polishing, andno issues.. No trimming is nec. for anything but the old rope seal.. cheers
Click to expand...
 
inertia said:
That may have been true for a reverse rotation engine, but I have successfully used the lip seal on many both rotation engines with no polishing, andno issues.. No trimming is nec. for anything but the old rope seal.. cheers
Click to expand...
Thanks G...I stand corrected.
 
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