Cam gear wear can be greatly minimized with a very thin machined washer between the gear and the bushing. The majority of wear is cause by the contact of "similar metals" - the bronze gear and the bronze bushing. Once they start to wear the gear now starts to move up and down and that causes the wear on the gear teeth. Put an .030 machined washer in there (commonly used with torrington bearings and wear will be ZERO. You could also use one of the "coated" gears being offered by various sources.