You don't want anything between the crank flange & flywheel. However, the bolts holes in the crank are open drilled thru and will wick oil past the bolt threads. I use a SMALL amount of locktite pipe sealant w/ teflon (like teflon tape in a tube). Locktite thread sealant works good most of the time but I trust the pipe sealant more. Don't use any type of RTV on the threads.
