[kingair]

I went thru 3 Dist. gears, 2 brass 1 steel, within a one year period and when the engine was being rebuilt for another problem it was discovered that the intake manifold had a slight tilt to it that did not allow the Dist. to sit perfectly parallel or go all the way to a good set position! The builder ground the manifold flush to allow a perfect seat and I have not replaced a gear since, or seen any type of uneven wear. The manifold was a single plane blue thunder. Just another thing to check for.