front main seal
 

I have an 8ba flathead with about 1500 miles on rebuild I used the one piece lip seal and have a leak. I am old and have always used the rope seal I left the spiral groove in the crank. Is that my problem or is it probably something else. Tell me about your experiences with li0 seal vs. Rope seal. I am using mobile one 5 w 30 and have very good oil pressure

Re: front main seal
 

I too tried the one piece seal, even used a seal surface renue sleeve, after about 2000 miles it leaked worse than any rope seal on previous engines. I removed the one piece, cut off the sleeved and installed a rope seal- still weeps a little but does not pour out. maybe the spiral for the rope seal caused it to leak???

Re: front main seal
 

Just an observation, the rope seal on my 110k Merc. had the normal seeping. After installing a PCV system the seeping virtually stopped.
This is because of the negative pressure created by the PCV vacuum.

Re: front main seal
 

Thanks for the tip I do have a pcv but have not checked function and flow

Re: front main seal
 

Hi Woody, been using the "neoprene" front seal for some time now with excellent results, never a single drop of oil ever.

Having said that you do need to use the correct sleeve to accomplish the best results. See the photo below, I show both setups.

Thanks, Gary in N.Y.

P.S. On a side note, if you have any type of "excessive" crankcase pressure issues, no matter the seal choice, you may experience leakage. Basically speaking you need an effective ring seal. Most times this becomes your primary issue!