Slant Six Forum
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Rear main rope seal
https://www.slantsix.org/forum/viewtopic.php?t=55852
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Author:  Feather_Duster [ Sat Jul 26, 2014 10:09 am ]
Post subject:  Rear main rope seal

I am considering using a rope seal instead of the modern rubber kind. Does anybody still use these? Were can I get one?

I also have heard that modern rope seals do not work well (something about lacking asbestos)... is there any truth to that? Anybody know the part number of the original seal?

Do the knurls on the crank need to smoothed if a rope seal is not used?

Author:  DadTruck [ Sat Jul 26, 2014 7:53 pm ]
Post subject: 

I am using a heavy early cast crank in my 83 D150 in place of the light weight cast crank.
the heavy cast crank has a cross hatch pattern at the rear main seal interface,
the lip seal does not leak much,, but it does leak, going to install a rope seal,,,

http://board.moparts.org/ubbthreads/sho ... er=6890472

the rear rope seals from this company get high marks on the internet, but I don't know if they are slant six compatable,,I'll give them a call next week
http://www.bestgasket.com/about_our_products.asp

Author:  SlantSteve [ Sat Jul 26, 2014 8:12 pm ]
Post subject: 

I just purchased an ACL brand ( Australian )lower gasket kit and it had a rope main seal and the flat rubber timing cover seal(as per original Mopar,not a V lip seal).They are very good quality kits and I feel they supply these seal types for a good reason.... I've seen the V lip style timing cover seals leak bad,no doubt due poor timing cover alignment,I fixed the leak on this engine by fitting the Mopar style flat rubber style seal...no more leaks. I feel the rubber rear seals probably have the same issues,if it's all spot on,they work....but if things aren't right.....and let's face it,we have 50 year old engines here....get that drip tray under your car! I would imagine the knurling on the crank can be an issue as well. Cheers

Author:  DadTruck [ Sun Jul 27, 2014 5:12 am ]
Post subject: 

Question(s)

guessing that rear main rope seals were used initially on slant motors,
from 1959 to ?

is that correct?
anyone know when the break was made to the lip seal?
was that concurrent with the steel crank?

is the block hardware, rear seal carrier.. the same for either seal?

Author:  Feather_Duster [ Sun Jul 27, 2014 7:56 am ]
Post subject: 

DadTruck - Keep us posted on what bestgasket says. The last thing I want to do is build this engine and have it leak.

SlantSteve - That pretty much summarizes what I have heard... if everything is lined up perfectly, the v-lip seals will work. The rope seals are supposed to be more forgiving. Good point about the timing cover seal as well... I hadn't thought about that yet.

Speaking of Australia, I found this: http://www.pentastarparts.com.au/store/ ... ail&p=2067
Not cheap though. Anyone know anything about these?

I don't know when they stopped using the rope seal, but I just tore apart my 1976 and it had a rope seal and a forged crank.

Author:  SlantSteve [ Sun Jul 27, 2014 3:00 pm ]
Post subject: 

Pentastar parts.....yes I know them...let's just say Id rather buy my parts direct from the USA.... or other local suppliers here...Enough said? I'm sure you will pick up a rope seal locally, at a far better price!Cheers

Author:  nm9stheham [ Sun Jul 27, 2014 3:50 pm ]
Post subject: 

I ran across that site yesterday....saw one part there for $48 AU that I can buy for $6 US.... !! The exhange rate is close to 1:1....

As for rope seals, I never had one work well, but that could be me; never have had issues with dozens of the ring seals.

Author:  SlantSteve [ Mon Jul 28, 2014 2:42 am ]
Post subject: 

Quote:
I ran across that site yesterday....saw one part there for $48 AU that I can buy for $6 US.... !! The exhange rate is close to 1:1....

As for rope seals, I never had one work well, but that could be me; never have had issues with dozens of the ring seals.
I fitted a v ring type seal to my old daily drive 2.6 sohc engine when I was changing timing and balance shaft chains. I did it as a precaution since all the other seals were pretty old and hard. Much to my frustration it leaked :roll: but after a few months it stopped,it was completely dry from then on! I replaced that engine a while back with another engine I had,new seals ,bearings etc....yep you guessed it,a small leak,and yep it stopped after a few months of use. The seals were good quality and once they settled in they were very dry. I think that perhaps the old rope seals cover a multitude of sins as far as machining and alignment goes,but from what I have seen they work pretty decent,maybe not as dry as a good rubber seal,maybe just a small smear of oil. Im assuming the seal design has the lip running on an area away from the knurling?? I'm happy to run the rope seal I have in my kit....but I'm not running out to pay $48 for the privilege :shock: ....I didn't pay that much more for the complete bottom end kit!

Author:  Feather_Duster [ Mon Jul 28, 2014 10:03 am ]
Post subject: 

Pentastar is definitely overpriced. SlantSteve, Where did you get your kit?

Does anyone have a part number for the original seal?

Anyone else prefer the v-type seals over the rope seals?

Author:  SlantSteve [ Mon Jul 28, 2014 2:17 pm ]
Post subject: 

I had a local machine shop supply it for me.... I have plenty of top end gaskets and really just needed a lower gasket set. To my surprise he had no problems supplying the kit in either Endurotec or ACL. A while back I tried to but a set of standard bearings and a cam bearing set for a slant.... The shops usual suppliers had no stock. I just purchased the lot from the USA to save him the effort of chasing them up locally. I had a set of mains, rods and cam bearings supplied and sitting on my doorstep for less than Penta$tar wanted for the cam bearings!

Author:  SlantSteve [ Sat Sep 13, 2014 6:33 pm ]
Post subject: 

Just as an update on Rope seals...the ACL gasket set I bought over here had a rope seal...but,when I unpacked it to soak in oil it felt very flexible,not like the usual stiff material . After installing it I was surprised to feel how free the engine turned over,very little resistance that is usual with rope seals. It felt a bit like stuffing a soft banana into the seal groove! After speaking to a few guys over here apparently there are rope seals....and then there is the new rope seals. One theory is the new ones are asbestos free. The unanimous opinion is don't use them,apparently the Oz Hemi 6 engines are having a lot of issues with these new rope seals ,to the point where a local parts supplier has come up with a neoprene replacement. So I am going to run a 2 piece Felpro neoprene seal in the slant just for piece of mind. Apparently the brand name "Real Gaskets" do a decent rope seal,or I guess a NOS part would be fine,but have never seen them out here. Hope this helps! Cheers .

Author:  Feather_Duster [ Thu Sep 18, 2014 9:33 pm ]
Post subject: 

Thanks for the update. I am interested to hear how the Felpro works out for you. I am actually still looking for a rope seal. Does anyone have some old part numbers????

I checked out Real Gaskets, but I did not see any rope seals. They do have some other /6 seals though.

Author:  classic ap6 [ Fri Sep 19, 2014 12:01 am ]
Post subject: 

Interested to now how you go with the neoprene slantsteve. I used one from hemi performance on a hemi 6 and it leaks

Author:  SlantSixDan [ Sat Sep 20, 2014 2:26 pm ]
Post subject: 

Key technique for avoiding leaks with a 2-half-circles neoprene rear main seal: offset the seams of the seal halves so they don't line up with the halves of the rear main bearing housing. The housing part line is horizontal, 9:00 to 3:00, so install the seal halves with their ends at about 10:00 and 4:00. A small dab of good quality RTV at each of the seal half ends, too.

Author:  Charrlie_S [ Wed Sep 24, 2014 5:00 pm ]
Post subject: 

Quote:
Thanks for the update. I am interested to hear how the Felpro works out for you. I am actually still looking for a rope seal. Does anyone have some old part numbers????

I checked out Real Gaskets, but I did not see any rope seals. They do have some other /6 seals though.
I might have found some rope seals. I ordered two sets. I'll let you know what shows up at my door.

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