Re: rear main seal

Posted by todd landis On 2015/5/26 22:57:01

I can give you the story behind my 1940 rear seal. I can also tell you that two longtime L.A. Packard mechanics have told me to leave the rear seal alone if it only leaks a bit, the modern rear rope seals do not last. On two occasions installed by experienced Packard men, started leaking within two weeks. This was about two years ago, and do not recommend the latest rope seal guaranteed not to leak, it does.
Why I ask is 1940 because the troughs are deeper and give very little support to the rope seal. Have been told it was corrected for 1941.
When my engine was rebuilt about twenty five years ago, would not leak for about 200 miles, then would start to leak. Had experienced mechanics replace a few times, did it my self a couple times over about a two year period.
While doing these replacements, would talk to many machine shops, looking for someone old enough that had experienced this, and had a remedy.
Finally one shop gave me the name and number of a fellow that had owned a company called L.A. Piston. A machine shop he had owned from the thirties, and actually worked with Studebaker, Ford companies on refinements with the engine rebuilding process, and issues with rear rope seals.
He told me several things. Make sure the seal is seated properly. Drill a small hole in the trough of the bottom cap, cut off the tip of a nail, and stick it in the hole point above the surface just a bit, to prevent the rope seal from shifting because of the rotation of the crank shaft.
And find wicking material. I had never heard of it, but he stated if you find a machine shop that had been around long enough, they will carry it.
After many calls, and driving around all the oldest machine shops in L.A. finally went to one, and the older gentleman said no has asked for that in probably thirty years, but I have a box of Fel Pro Soft Wicking Material. Did you know it is asbestos, and not allowed to have it!
I said oh? Can I have just a bit?
He said I am not supposed to have this anymore, and not used it in thirty years, you take it. When you use it make sure you have a mask on.
Wicking material is a soft fibered oil soaking fibre material that expands to fill gaps. In this case where the rope seals meet, and a gap can happen.
I did the nail thing, and used the wicking material on both sides where the seal comes together. After about 14000 miles, it is just now starting to leak, and compression is starting to drop, so for me it lasted the life of the engine, now time to rebuild.
That's my story use anything that might help.
I am sure someone has better ideas.
And being farily new to Las Vegas, can anyone recommend an experienced engine machine shop? Thanks