Properly Matching Your Camshaft and Distributor Gear - Engine Builder Magazine

Properly Matching Your Camshaft and Distributor Gear

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:

1. Cast Iron

2. Composite (offers great life, conforms well to the mating cam gear, and is compatible with ANY camshaft gear material)

3. Melonized or hardened steel
(material that OEMs use with factory roller cams; many aftermarket
distributor manufacturers use these as the default gears for their

4. 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:

1. Cast iron distributor gear

2. Composite distributor gear

If you have an austempered ductile iron hydraulic or solid roller cam, your two options are:

1. Melonized or hardened steel distributor gear

2. Composite distributor gear

If you have a billet steel hydraulic or solid roller cam, your two options are:

1. Bronze distributor gear

2. Composite distributor gear

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

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