It was suggested to me by someone who knows, be sure who does the bearings knows what he's doing, has the variety of balls that may be needed. Like you say, if they are too tight it not going to do much for you.

I personally tried them just to see if they were any better. I have ceramic bearings in a couple of engines and can't really tell any difference. I thought one of the big attractions to ceramic bearings is that they would survive on less lubrication. For supplied fuel events, there's no gain to be had there.

the ceramic bearings really helped in one engine in particular, the Nellie .36 combat. The rear bearing in this engine was pushed to the limits and without regular care and feeding could become a problem. If you have ever blown a rear bearing then you know that it destroys about everything, then bends the crankcase for good measure. At the end of the season I would send mine to Henry for new bearings and a look over.
it's interesting that after we lost the nitro plant in the U.S. years ago and began using Nitro from China that rust began to appear on the ball bearings. One of our more scientific guys (Norm McFadden) traced it to the nitro.

I don't really know the particulars on the various sizes of the balls or where to source them. I'm sure Greg could answer you, possibly he's on this board??

Les

When Henry Nelson made the last run of .36 combat motors last year, he offered an upgrade to ceramic bearings for an additional $12. Sounds pretty cheap to me. Considering the engines were $360 each.