Main seals:

nebrfox

Junior Member
Does anyone make a better front and rear main seal for the 40 flathead than the old rope seals? Changed mine twice and still have leaks or am I doing something wrong. I put silicone on the ends when installing the pan. Any suggestions would be appreciated.
 
They usually work just fine...
If the surface on the crank is ok and you put some grease on it to prevent a dry start it should work.
 
I put new rope seals in my '51 Merc engine before I installed it. I think mine were "Fel-Pro". Anyway, they came in a "kit" that contained a razor knife and a trimming guide. I was careful when I installed them, followed the instructions, and I have no leaks. Now, if I had been as careful and installed a new drain plug gasket, I'd be in "Fat City". I'll do it during my next oil change.

The guy at the machine shop who did the major work on my 258 incher installed a one-piece neoprene seal. I am in the process of getting the engine up and running, and it will be interesting to see how that works out. I had one for the Merc, and decided not to use it when I saw how "sloppy" it fit in the seal cavity. Mine was from "Speedway"; I don't know where he got his, but he claimed it was "better".
 
Used the Offenhauser one piece seal on the front of my rebuild. Less than 1000 miles on it, but no leaks yet.
 
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