Trojan Boat Forum

Have a fair bit of experience building 4 cyl. race motors...not a stranger to this kind of thing, but I would like to know who might have done a rear main seal on a 225hp LM 318?

My question for you would be, which seal did you choose..old two piece original rope seal?...or the new style rubber seals?

Have them both, and I'm not dropping all the bearing caps or crank to replace the seal.

Interested in those who have experience with this repair, or know first hand of a fellow boater who has.

Thanks,

Paul

Are you sure it's the rear main seal and not the pan gasket? If it's the main you'll have to drop the rear cap. It really doesn't matter what seal as long as it's installed properly, lip forward with some sealant. You might even rotate it a little so the parting lines don't line up with the cap to block surface.

Reel Easy wrote:Are you sure it's the rear main seal and not the pan gasket?.

I'm hedging the worst case scenario....obviously no sure way of knowing until the velvet drive is separated and the flywheel is removed.

Would be nice if it were only the pan gasket.

I've read many a thread, both Mopar and marine engine, those claiming the rope seal is the only way to go, and....those claiming the rubber (neoprene) is the only way to go. Of course their choice was the result of having tried the other and were ticked with the leaking results...

well I was there but did not mess with the rear main seal. Engines were Jasper re-manufactured so left alone used new pan gaskets and a new seal at the timing cover. That said was worried about the timing end of crankshaft as original engines used a slinger and the new ones and a new kit did not show use of slinger. I did not use the slinger and no leaks. But that is at the wrong end of your engine. I would think the Mfg of these engines would not digress back to a less efficient seal so would use what is provided today. Me thinks the non rope one would be best.