Rope seal for rear main

[Richard Lorenz]

I have a crankshaft that was altered about 30 years ago to use a Chevrolet-type rope rear main seal. I have the rope, but I don't know how to use it. Can any old-timer advise me? I don't have time to have the crank redone to use a modern seal. Thanks

 

[Craig Lewis]

Here's some pictures of an insert motor I built using the rope seal. I trimmed it leaving aprox 1/8 tp compress & gucked it up with thick permatex including the cap face where it meets the block.
Although the general concensus was to cut off the slinger, I opted to round the edge and polish the slinger with crocus cloth in my lathe. The picture shows how the soft rounded edge imbeds into the seal.
This is just an experimental idea to attain a more positive seal...plus I've retained the slinger in the event my idea is garbage & I need to go back to original.
The engine hasn't been started to date.

 

[denis4x4]

I soak the rope seal for at least 24 hours before installing it. Since I started doing that, no more leaks and easier to install.

 

[Patrick L.]

I soak a rope seal, roll it into the groove firmly and for a rear seal,cut off flush.. For the front, leave it about 1/8" proud..

 

[RichPA]

Rich, is this an engine you are putting together or are you doing an in the car repair?If so, there is a tool called "Chinese finger" to install it.There is also a removal tool for the old one.

 

[Jim Brierley]

How do you hold the rope against the back of the cap? I've done a lot of Model B's but am having trouble with my first pressured A. The upper, in the slinger, is easy, but in the cap the rope won't stay back as I try to give it pressure against the crank.

 

[Craig Lewis]

I'm not sure what you mean Jim.
The rope fit snuggly into the grooves on mine so I don't see how it can move forward or back, but maybe I've missed something...
I know from reading your posts over the years that you have a ton more experience than me with this old stuff... I just don't understand the question.

 

[Richard Lorenz]

Update: I have decided to go for machining the crankshaft to fit a modern seal (if I can find someone who will let me use their lathe). I expect to use the cork/neoprene type seal.

I did get some advice from an experienced Model A person that I will pass on. As with all seals, the seal must rub on a location that is concentric with the rear main bearing / journal. Many crankshaft grinders do not keep the regrind concentric with the original crank centerline.

For a rope seal that rubs on the original slinger, my expert said that the tapered side of the slinger must be cut away for maybe about 1/8 inch. Otherwise the rope seal will not work according to this person. The cutting should be done as described above. Use a 4-jaw chuck with a dial indicator on the rear journal to be certain that the crank and seal area are on the same centerline.

This small modification to the slinger might help hold the rope in place.

 

[Jim Brierley]

My cap has only a very small groove so on the front side of the rope there is little support and the rope doesn't stay in place. Perhaps my cap has been modified? I'll take a look at other caps and compare but I am going to put is a Burtz seal anyway.