340 Rear Main Seal Replacement

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I faced the same choice recently and went with the "new and improved" rubber seal over the old rope seal. In talking with my local machine shops and others still in the business, that was the consensus. If you definitely decide to go with the rope seal, let me know. I have an extra in an old gasket set.
 
I was asking this same question last winter, in the end, I used a Fel-pro seal, # BS 40245. Probably the equivalent to your Viton. Summit Racing carries rope seals, someone gave me the number back then, it was for a GM, maybe a Buick. I don't know if I can find the number. I did what I was told to do by Mike at B3 Racing and my oil leak is gone. Seems like I explained all of this awhile back, wasn't it you?
 
cudamark said:
I faced the same choice recently and went with the "new and improved" rubber seal over the old rope seal. In talking with my local machine shops and others still in the business, that was the consensus. If you definitely decide to go with the rope seal, let me know. I have an extra in an old gasket set.
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Since I am not a Gold member, I posted these here.

Here is one of the two pieces that go into the grooves on each side of the rope seal. A small part broke off, so the total length is about 1 1/2". Does your set have these in it?

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CRUZE 418 said:
I was asking this same question last winter, in the end, I used a Fel-pro seal, # BS 40245. Probably the equivalent to your Viton. Summit Racing carries rope seals, someone gave me the number back then, it was for a GM, maybe a Buick. I don't know if I can find the number. I did what I was told to do by Mike at B3 Racing and my oil leak is gone. Seems like I explained all of this awhile back, wasn't it you?
Click to expand...

I know we discussed the location of the RTV application a couple of weeks ago, but I don't think so on the GM/Buick rope seal thing. Appreciate the above info.
 
Yes, that Fel-pro # does. The half that goes in the main cap. I cut that tab off that is supposed to go out under the pan, thin smear of silicone from the main seal out to the edge of the main cap. When you have the main cap in and torqued, fill in that main cap edge where it hits the block. Those two sides and same for the timing cover corners, silicone.
 
I could not find that rope seal number, you will be ok with the new seal.
 
Keep in mind that with 86,000 miles, there is a fairly good chance (in my opinion) that the crankshaft may have a bit of a groove in it where it has spun inside the rear main seal billions of times. I have seen it many times. And often, a stock seal won't help much. I have seen over sized rear main seals for chevys, but I don't know about Mopars. I really do hope you come out OK.
 
@DustyEd was just reading your thread and wondered if you had changed it and how you made out!
I am looking into changing mine and wasn’t sure if you had any snags or tips! Thanks
 
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