Timing Cover Oil Seal

[ktb]

The oil seal I pulled out of my '51 B3B is Chrysler part number 1088602 (left) which correlates to National 6186.  The oil seal that came in my Fel-Pro gasket kit is National 411431 (right), which has the oil slinger (?) lip and no recessed area to push through the front of the timing cover.  I've read a couple anecdotes here where the slinger rubbed on the timing chain - it looks like the slinger style would sit about 3/16" closer to the chain than the original style.  Should it work for me if my timing cover is not dented in, or should I play it safe and track down a National 6186 (leather) seal?  My engine has the oil squirt tube and doesn't need a slinger.  Thanks!

 

 

 

 

 

[bkahler]

You definitely do not want a leather seal, they are out dated technology. 

 

I'm not sure what seal you should get so hopefully someone will chime in with that info.  

 

[Robert Harrison]

The oil tube supplies oil to the gears and chain.  Typically an oil slinger which is like a big washer is there to fling excess oil away from the seal to prevent excessive leaking.  I dont think you can get a new leather seal anymore and probably dont want one.  Should you decide to get a NOS leather seal they are around be sure to soak the leather over night in motor oil and work the leather to loosen it up with a wooden handle from say a hammer.  I would check clearances and use your best judgement but the timing chain/sprocket wont move much just a few thousands of an inch.  Its been too long but I think there was an oil slinger check the parts book.  3/16 is a lot of space.  you can go to Rock auto and put an original number in and it may give you some choices.  Also I built this list of parts a few years back for our 39-47 Job rated trucks some of this will work for you   See the attachment below  Bob Harrison  

39-47 Group Parts List DodgeRevised7-31-2013 (1).xls

[ktb]

Thank you for that suggestion - RockAuto's part interchange lists SKF 21820.  I can't tell if it's more like the original or the one with the sharp lip. 

 

And thank you for clearing up the oil slinger for me - I was not visualizing what it was or how it would get chewed up by the timing chain. 

 

Yes, I agree - 3/16" is a lot, but that's what I'm measuring since the National 411431 outer side can't protrude out the front of the timing cover hole and inner side has a sharp lip.

[JBNeal]

Leather seal + oil slinger combo was replaced by the rubber lip seal because the manufacturing technology improved,  making the rubber seals cheaper and more reliable than leather seals.  Leather seals are still available in certain applications where oil is under low pressure, but opt for the rubber as leather requires oil contact to stay pliable; sitting for long periods will dry out the leather, leading to premature failure.

 

A problem with the older seal technology was that as the seal material aged, it became harder and less pliable.  This would lead to a small groove wearing into the sealing surface that a new seal would not make adequate contact with, leading to leaks.  Speedi-sleeve is your friend when this happens. 

[ktb]

OK, I guess I will try the National 411431 seal and check for interference.  Does anyone know if there's a difference between it and the SKF 21820 seal?  I am concerned about the raised lip seal based on this post by Dodgeb4ya and wonder if the SKF seal is flat on the inside.  Or is the metal lip supposed to go to the outside? (comment by Powerhouse)

 

https://p15-d24.com/topic/17364-timing-chain-cover/#findComment-163655

 

"A note of caution on the 2 styles of front cover seals. The one seal is flat on the rear side. The other style has a raised curved lip/oil slinger on the back/chain side of cover. The t/c picture shows a later style slinger type oil seal. This one was rubbing against the crank gear because of a slightly caved in timing cover! You can just see the metal shavings in the cover pic. It was making a slight rubbing noise. Took it out of a "Overhauled " engine. The pic of the timing chain is a modern replacement chain ( narrower) than original DPCD chain installed on the old DPCD gears-WRONG! Always replace all 3 pieces as a matched set.
Bob

Edited July 28, 2015 by Dodgeb4ya"

 

"as per VPW's technicians....that's installed backwards. Metal lip out, rubber seal in.

Edited March 29, 2010 by Powerhouse"

Edited February 3 by ktb

[JBNeal]

That linked thread touches on some good pointers, as the inexperienced flathead engine rebuilder might miss some details on these timing chain covers.  The cover sheet metal needs to be checked for damage that needs to be corrected prior to reinstalling, as the flanges can be tweaked and the seal plane can get caved in from improper seal installation.  Centering the cover seal on the crankshaft also requires care as there is some wiggle room here that can lead to leaks.

 

I recall hearing about some seal leaks that were caused by that oil tube pointed at the seal instead of the chain sprocket, with various opinions as to how that could happen.  So care needs to be exercised at each step of the rebuild, as getting in a hurry and cutting corners can lead to an expensive lesson.

[ktb]

Thanks, does anyone know which side of the new seal faces out?  My concern is the sharp protruding metal lip. 

 

 

Normally an oil seal has a flat side and an open side, and is pressed on from the outside toward the inside, with the flat side facing out, and the open side facing the oil or high pressure side.  But as we know, on our timing cover, installation requires that the seal is pressed inside-out.

 

In the case of the new seal, the "open" side has a sharp metal lip, but either side is flat enough to drive the seal in from.  It will go on either way, but do you want the sharp lip away from the crank sprocket or toward it?  I've been asking VPW the same question, but I don't know if theirs is the same sharp-lipped seal.  If interference is a concern, the sharp lip should face outside the timing cover.  But that leaves the "open" side to the outside, where dust and debris could potentially accumulate. 

 

Why they didn't design the new seal like the old one is beyond me.  The old one has a flat side that you press on and a shaped side that protrudes perfectly through the timing cover opening; both sides are closed.  

 

If the main concern is that the rubber lip is oriented the same way as on the old one, then the new seal should be installed with the sharp metal lip facing inside.  And I think that is the way most people on here have done it.  But why on earth is there a sharp metal lip at all?

 

Clearly I am overthinking this...

 

P.S. Just received confirmation from VPW that they say the sharp metal lip faces outward...

 

It probably will work either way, but assuming interference is not an issue, based on the rubber seal orientation I think having the sharp metal lip on the inside would be less likely to leak oil. 

 

The gasket for the timing cover oil seal that came with the set will not fit around the sharp metal lip, so there's another piece of evidence that the sharp metal lip should face inward. 

 

Edited February 4 by ktb

[Dodgeb4ya]

The extended lip faces the crank gear.

If there is a spring in the seal that spring and open part of seal should always face the oil side of crankcase/ crank gear.

Make sure the timing cover is not damaged/bent from other seal install or removals in the past. Properly support the T-cover when installing the new seal.

Lube the seal lip and apply a small amount of sealer on the OD of seal before installing seal.

Use the proper diameter driver to install slowly and carefully.

[Robert Harrison]

On 2/3/2025 at 3:49 AM, JBNeal said:

Leather seal + oil slinger combo was replaced by the rubber lip seal because the manufacturing technology improved,  making the rubber seals cheaper and more reliable than leather seals.  Leather seals are still available in certain applications where oil is under low pressure, but opt for the rubber as leather requires oil contact to stay pliable; sitting for long periods will dry out the leather, leading to premature failure.

 

A problem with the older seal technology was that as the seal material aged, it became harder and less pliable.  This would lead to a small groove wearing into the sealing surface that a new seal would not make adequate contact with, leading to leaks.  Speedi-sleeve is your friend when this happens. 

Hello JB  so are you suggesting not using a slinger washer with the rubber seal?  Just confirming.  I see your point but this is new to me.  Its also possible to install seals backwards although I dont see it here but with industrial seals it can happen so I thought I would make sure people knew that typically the lip folds inward when installed and be sure to lube it well and use a sealant on the outside of the seal when installing it.  

[Robert Harrison]

Im sorry this is so confusing.  Oil l seals only go on one way.  Modern oil seals have a lip.  The lip has to intersect the shaft in just the right way to form the seal.  So it is about understanding how the lip is supposed to sit on the shaft.   The better manufactures all have technical support.  I suggest you call the manufacture of the seal you hope to use.  When you look on their sites they have drawings.  look at the way the ridge of the seal rides on the shaft it will become more obvious.  Im having trouble following this metal lip thing.  All I can say is if you have doubts about this part dont use it they are cheap and you will gladly pay many times the money.  Obviously if the dimensions are not right then dont do that.  Seals come by dimensions so there are sealed seals, open seals, double lip seals etc  Can be different by design and manufacture but all have the same shaft, OD and thickness or maybe not.  They are listed by dimensions.  The seal I used was open on the chain side and had a spring wound such that it helps push the seal closed radially on the shaft.  So, there is only one way it could be installed with metal side out and open side with spring on the inside.  If I installed dozens of these I would by now know which seal was the best choice but I dont so we will see.   Follow the instructions given above to install it radially use sealant and on the face if the seal presses into the timing cover from the inside to a lip that is the face of the timing cover.  RTV probably a good choice I use the old fashioned red stuff cant remember what it is called.