Timing chain vs. gears

[Jerry Clayton]

The gear drive info presented here is not for the type of gear drives that any top fueler runs---this is the Pete Jackson type gear drive that came out many years ago to replace the old link type chains and plastic/fiber gears--the type of cheap gear drive up to then required a reverse ground cam to work--the Pete Jackson type would work with standard rotatation camshaft

The Donovan, Kieth Black( built for Black by Donovan) and the copy cat Milodon gear drive used a single idler gear that had the gear mesh set and doweled to the block. This type gear drive does not push the cam upwards as the gears mesh on there proper lines and the cam turns in place---the Pete Jackson drive has the gear driven between the crank and cam forcing them apart causing the wear to the top of the cam bearings.
However they are expensive in todays world------

Jerry