NOS Rear Main Asbestos Rope Seal

[MarkH]

Not mine. Very hard to find when trying to avoid lesser quality modern substitutes.

https://www.ebay.com/itm/JEEP-WILLYS-MB-GPW-CJ-NOS-ROPE-REAR-MAIN-SEAL-1-pair/333102924654?hash=item4d8e7b436e:g:ePkAAOSw-R5cacPw:rk:1:pf:0

[pjkaiser]

There are two key words in the description below that would suggest using a new "RUBBER" STUFF!!   Those two words are "INSTALLED PROPERLY".

How many of you know anyone who, not only has done this, but has also done it "PROPERLY"!!!   They can be tricky, they must be soaked before hand and they must be crushed and trimmed properly to work, all very critical to a good non leak install!!!  My suggestion, Go for the NEW RUBBER SEALS.

"Installed properly these work better than the new ribber stuff".

[MarkH]

Don't know about other engines here but there are no "rubber" type rear main seals produced anywhere for F-head 6cyl engines.

Jeep threads are loaded with failure stories of modern 4cyl synthetic seals due to wide machining tolerances back in the day...……..and guys looking for these OEM seals rather than poor material modern substitutes to re-do them.

Sabo in Brazil makes a far superior F-head rear main rope than the current USA generic "one size fits all best asbestos substitute", Graphtite.
I tried that once, never again. Couldn't find a set of these at the time and went with the Brazil version for my own re-do. Good stuff but definitely harder to get and more expensive.

EDIT:
Just for clarification, some Jeep & larger military vehicle collectors have seal journals as much as plus or minus 20 thousandths so unless they're in the "sweet spot" for modern 2 piece synthetics, undersize leaks, oversize self destructs (then leaks), sometimes feeding the bits into the oil galleries.
The OEM asbestos rope often had a material that swells with contact with engine oil, as does the Sabo rope. According to Bestgasket tech support, their Graphtite rope has no ability to swell at all due to not having those materials. You get what you compress it to and that's it. Also, the Graphtite material is so slick the cap seal journal requires a locating pin (included) to be drilled & driven in to keep the Graphtite from rotating & self destructing. As their instructions state, it's easy to cut with the included knife.
That knife couldn't cut the Sabo material and each of the 4 Sabo trim cuts dulled a brand new utility blade. Just guessing, Brazil produced so many more F-head engines, for so many more years than total US production they may have been more vested in producing a viable asbestos substitute.

FelPro made an asbestos substitute for a while but it had such a bad track record it was discontinued last I heard.

Bestgasket serves a good cause producing generic gaskets for numerous obsolete engines, but sometimes OEM quality is worth looking for.