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Rear Seal Cap Gasket
https://www.slantsix.org/forum/viewtopic.php?t=61184		 Page 1 of 1
Author:  T2true [ Thu May 25, 2017 10:20 am ]
Post subject:  Rear Seal Cap Gasket
1968 225 Slant 6

This is my first time working on this engine. I'm to the point where I'm installing the rear seal cap and its associated gaskets/seals (Image 1 from here). Where the L-shaped seal sits on the block and protrudes away from the cap is causing much confusion (Image 2 ). Its position impedes on both the cork pan gasket (Image 3) and the rubber/neoprene gasket that goes between the rear seal cap and the pan. That's three different gaskets merging at one location (Image 4).

Now, I have read multiple (older) articles/posts here and here that say to leave that impeding tab in place and let the cork sit down over the tab. This makes no sense to me at all. Gaskets (like the pan gasket) should sit flat on their mating surface, not protrude in a hump-like state, right? Furthermore, if the tab is left, the rubber/neoprene gasket that goes between the rear seal cap and the pan will also sit on top of it (the tab is right in the middle of the cap). I can't fathom how that will create a good seal and not leak.
What's been indicated is that the tab will help align the cork gasket and keep it centered and in place. However, with products like Permatex High Tack Gasket Sealant, the tab is not needed to restrain the cork.

I'm thinking of trimming the tab back to flush with the cap and laying down some RTV to fill in any void.

Does anyone have any feedback on this?


Thanks,
Ted
Author:  DusterIdiot [ Thu May 25, 2017 4:14 pm ]
Post subject:  Yep...
Quote:
I'm thinking of trimming the tab back to flush with the cap and laying down some RTV to fill in any void.
That's what I ended up doing on the last couple of blocks... I even went so far as to fill some RTV in the crevice where the gasket is just to have one more line of defense if the cheap felpro 'rubber' didn't seal right between the pan and the rear seal retainer...
Author:  T2true [ Thu May 25, 2017 8:17 pm ]
Post subject:  Re: Yep...
Quote:
That's what I ended up doing on the last couple of blocks... I even went so far as to fill some RTV in the crevice where the gasket is just to have one more line of defense if the cheap felpro 'rubber' didn't seal right between the pan and the rear seal retainer...
Thanks for the feedback. I'm really leaning in that direction. I'm still baffled as to why the gaskets were made that way at all. Even the machine shop that should know - and from where I received the gasket kit - had no idea. Sheesh.
Author:  Doctor Dodge [ Tue May 30, 2017 9:28 am ]
Post subject: 
The overlap between the main seal cap "L" pieces and the cork pan rail gaskets was just the Chrysler factory's way to get a good seal with-out a lot of assembly time & "fuss".
This method allowed the cork rail gaskets to "float around" a bit, with-out creating a gap. where oil could get thru.

The rubber cap gasket, at the back of the pan, basically provides the
crush points and in theory, the rubber has a little compliance, to accept the "double thickness" of cork over rubber, that it covers.

It worked pretty good for the 12.5 million SL6 engines produced over the years but I find that I need to glue everything down so the "ends of the "L" tabs do not slip-out from under the cork, when compressed.
DD

http://www.slantsix.org/articles/gasket ... n-seal.htm
Author:  T2true [ Wed May 31, 2017 7:32 am ]
Post subject: 
Quote:
The overlap between the main seal cap "L" pieces and the cork pan rail gaskets was just the Chrysler factory's way to get a good seal with-out a lot of assembly time & "fuss".
This method allowed the cork rail gaskets to "float around" a bit, with-out creating a gap. where oil could get thru.

The rubber cap gasket, at the back of the pan, basically provides the
crush points and in theory, the rubber has a little compliance, to accept the "double thickness" of cork over rubber, that it covers.

It worked pretty good for the 12.5 million SL6 engines produced over the years but I find that I need to glue everything down so the "ends of the "L" tabs do not slip-out from under the cork, when compressed.
DD
Thank you for the feedback.

Regarding the rubber cap/pan gasket, I have two questions:
1. With the double thickness, how do you address the "bunching" that will occur inside the pan rim when it sits on the cork gasket that sits on the "L" gasket? It it not manufactured any shorter to accommodate that thickness.

2. What is the best installation method for the rubber cap/pan gasket - place on the cap and then install pan, or place in pan (with rubber alignment pins) and install the whole thing? If on cap, should it be glued/tacked to the cap? I can't get it to form to the cap and stay in place due to its rigidity.
Author:  Rick Covalt [ Wed May 31, 2017 2:20 pm ]
Post subject: 
Quote:
I'm thinking of trimming the tab back to flush with the cap and laying down some RTV to fill in any void.
I have on the last few engines I assembled and I have not had any leaks from that area.
Author:  T2true [ Fri Jun 02, 2017 8:39 am ]
Post subject: 
Okay...I called Fel-Pro (maker of gasket kit - Sealed Power 260-1004) about the rear cap "L" gasket. They said to cut it off flush with cap and add RTV. That will give room for the rubber pan gasket that goes over the rear cap.

I hope this helps someone out there.
Author:  Doctor Dodge [ Fri Jun 02, 2017 9:22 am ]
Post subject: 
Quote:
Regarding the rubber cap/pan gasket, I have two questions:

1. With the double thickness, how do you address the "bunching" that will occur inside the pan rim when it sits on the cork gasket that sits on the "L" gasket? It it not manufactured any shorter to accommodate that thickness.

2. What is the best installation method for the rubber cap/pan gasket - place on the cap and then install pan, or place in pan (with rubber alignment pins) and install the whole thing? If on cap, should it be glued/tacked to the cap? I can't get it to form to the cap and stay in place due to its rigidity.
Best to answer #2 first:

2. The rubber oil pan to main seal cap end gasket installs into the oil pan. It has small "pull-in pins" that insert & pull thru & seat into small holes, in the oil pan. Use small pliers to grab the end of each 'pin' and stretch it thru hole and then seat it onto the pin's larger shoulder

1. The over-lap & double thickness is engineered to crush everything together, as the rubber cap end gasket compresses the cork to rubber "L" overlap.
When installed, you will notice that the cork rail gaskets are a little short and to not come right up to the main seal cap so there is a little room for the compressed cork to "spread-out" as it crushes down.
Basically, the cork is the "filler material" in a rubber end gasket / cork / rubber "L" piece sandwich.
DD

Image
Author:  T2true [ Fri Jun 02, 2017 1:13 pm ]
Post subject: 
Quote:
Best to answer #2 first:

2. The rubber oil pan to main seal cap end gasket installs into the oil pan. It has small "pull-in pins" that insert & pull thru & seat into small holes, in the oil pan. Use small pliers to grab the end of each 'pin' and stretch it thru hole and then seat it onto the pin's larger shoulder

1. The over-lap & double thickness is engineered to crush everything together, as the rubber cap end gasket compresses the cork to rubber "L" overlap.
When installed, you will notice that the cork rail gaskets are a little short and do not come right up to the main seal cap so there is a little room for the compressed cork to "spread-out" as it crushes down.
Basically, the cork is the "filler material" in a rubber end gasket / cork / rubber "L" piece sandwich.
DD
Thank you DD for getting back with me. I really appreciate it.
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