Matching camshaft and distributor gears is one of the most critical, yet often overlooked step in engine assembly. The proper distributor gear for your camshaft differs by both the material and the kind of lifter for which your camshaft was designed. Using the wrong material can lead to premature gear wear, possible camshaft wear and ultimately engine failure.
First off, no steel distributor gear is compatible with both flat tappet and hydraulic roller cams. This is because hydraulic rollers can be made from two possible materials and either of those materials requires a different gear than the flat tappet cam. Regardless, a steel gear is not compatible with a cast iron flat tappet cam.
Distributor Gear Materials:
- Cast Iron
- Composite (offers great life, conforms well to the mating cam gear, and is compatible with ANY camshaft gear material)
- Melonized or hardened steel (material that OEMs use with factory roller cams; many aftermarket distributor manufacturers use these as the default gears for their distributors)
- Bronze (conforms well to the mating camshaft gear and will not damage the camshaft gear, but it is a self sacrificing gear intended to be used in race applications only and should be replaced about once a year)
If you have a cast iron hydraulic or solid flat tappet cam, your distributor gear options are:
- Cast iron distributor gear
- Composite distributor gear
If you have an austempered ductile iron hydraulic or solid roller cam, your two options are:
- Melonized or hardened steel distributor gear
- Composite distributor gear
COMP
Cams recommends the composite gear because it is compatible with all camshaft gears – flat tappet, austempered cast iron cores, and billet cores. If the steel gear is not hardened, it is not compatible with either of the roller cam types.
Note: If you have an austempered core hydraulic roller cam and a .500? shaft distributor with a steel gear, verify with the manufacturer of the distributor that the steel gear they use is a melonized or hardened steel material and it will work fine.
–Tech Tip courtesy of Comp Cams
