Rope Or Neoprene?

Rear main seal, that is. I have the rope one, watched a video where they rolled it with a socket and slipped it right in. Didn't go that way with me, no surprise there. So reading around the net and find there's a lot of back and forth as to which style is better, from an installation and reliability standpoint. What is the general consensus, if there is one?

 

Neoprene

 

X2

 

Easier to install? Or just superior overall?

 

Willys Rear Main Seal Best Available USA. MB, CJ2A, CJ3A, M38 A1. F134 or L134. | eBay
I bought one of these based on forum recommendations. Went in well and is working so far.

 

Got some of both in the shop. Waiting for time to install. Good information. I think I'll try the Neoprene seal when I get back around to the 64 F Head.

Dave

 

I ordered one just now. Interestingly, his web site is 31$ with 10$ shipping, but on ebay he's 28.75 and 3.70 shipping. Anyone know of an install video for this seal?

 

I think the neoprene seal is superior. I have cheated when installing one. I loosened all the main bearing caps slightly, allowing the crank to drop a very small amount. This only works with the transmission remove too.
-Donny

 

We got by installing it by having one guy work the seal while the other turned the crankshaft with a wrench on the pulley nut.

 

Engine is out, so hopefully wont have to do that.

 

ALL depends on the condition of the seal surface on the crank and its diameter. Most machine shops can not grind such a narrow surface I had to go to a true Crankshaft grinding out fit the OLD school kind. And this was in the Portland Oregon Market. Make sure the Diameter falls within the recommended size (do some google searching for Willys Rear main seal crank diameter there is actually an industry alert on this out there to be found). My crank could not be made perfect and remain larger then the min given so I went to the Rope on advise from the Crank grinder.

 

Was trying the neoprene (best gasket 3b71) in the cap and block without the crank in place, just to check fit. Gasket halves stand a little proud on both cap and block. Keeps the cap from sitting flat. I didn't torque the bolts. Is this normal? Anyone ever have to trim? Also, why are the round rubber plugs in the holes on either side not used with other seals? Am I missing something?

 

You didn't say for what engine, but if it's the 225, Neoprene for sure. Not only is Neo just better, but the rope seals from Fel-Pro are too big. I tried several sets and none fit without jamming the crank. The diameter they used is quite a bit thicker than OEM. I gave up with the ropes and went Neo.

John

 

I also had to compress the seal halves a bit to seat the bearing cap. I think this is to help give it a snug seal all the way around. If it was a loose fit you would get leaks.
I also suspect the rubber plugs are used with all seal types, you need something in there. Perhaps the seal kit you purchased is more complete than some others.
We used Permatex Aviation #3 on the top surface of the bearing cap between the rubber plugs and the main seal. Just a very thin coat.

 

Im having trouble getting the rubber dowels in on the sides of the rear main. Do you set them in before or after putting the cap on? I cant get mine to go in either way. And still not sure about the seal, seems to be holding the cap up.

 

Hmm I don't exactly recall how I set the rubber dowels. I think I got them started before I pushed the cap in. Certainly I drove them up before I fully tightened the cap. Do you have photos of what you are dealing with?

 

I finally got them in. Had to set them in the block side grooves and slide the cap down them. Also smoothing the edges of the cap groove with a file helps, mine were rough and kept catching the rubber. Do you just trim the excess sticking above the deck?

 

No the Rubber plugs should compress when you tighten the rear cap down.

 

Are you asking what to do with the tails of the cylindrical rubber plugs that hang below the block? Like where the oil pan mates? Mine hung below enough that had to do something to be able to install the oil pan. I trimmed them so there was maybe 3/16-1/4" sticking out. That way the oil pan compressed it a bit.

 

Did you read the FSM? Section D-77 says "do not trim these packings. the packings are of predetermined length that will cause them to protrude approximately 1/4" from the case." I figured Felco or whoever could be depended on to make them the correct length. How can you cut them square or smooth enough to seal. Good luck.