Rear Crank Main Seal


I have found quite a few posts on this subject, but they are dated, and I am about ready to put the crank back in my engine so figured it would not hurt to ask. I have purchased the Fel Pro rope seal for the rear of my 455. Had my parts for a while and after some research see a lot of recommendations to use a 500 CI Cadillac seal or seals from Fords. Some say small block ford, others say Ford 460. When I took my motor apart, it had a rope seal that was not leaking. Is it really not a good idea to put a new rope seal back in? and is Fel Pro a good part? If something else is likely to give me less grief, what is suggested? Thanks! Going back to the garage to finish putting new cam bearings back in.
I have been using the Best Gasket seals with success. I have no reason to believe the FelPro are anything but good. I know many don't like rope and "upgrade" to a more modern seal.
What I like about a rope seal is it does not wear a groove into the crankshaft.
Follow the instructions carefully and I am sure you will be successful. I always run my engines for at least a half hour to check for leaks. They are much easier to find and fix before installing the engine.


Active Member
In my experience with my 401 Nailhead I tried twice unsuccessfully to install a Rope seal. It does require a skill developed by several trial and errors. After that frustrating experience, I had an expert engine mechanic install a rubber seal and it works great! It is hard to argue that rope seals have been replaced in modern engines by rubber seals for good reasons.
I for one would like to know what "magic" is required to get the rope seals to seal. We have been having problems here in the shop with them as well. We all know that the original equipment was "rope-type", and in keeping with what Bob says, they do not affect the crank journal, so this is good. Looking carefully at the ones with issues, I feel the rope diameter has changed, and possibly the material. Asbestos is no longer permitted. So does anyone know if there is a correct rope and if so what techniques one needs to know to install it for good oil control?


Active Member
IMHO Rope Seals have too many variables to be able to produce a good result in 1 try for an inexperienced person like myself: Rope materials and dimensions, the rope rate of absorption of lubricant, skill in the application to the right depth, cutting the frayed ends cleanly, etc. So why put yourself thru the aggravation if modern rubber seals work better?