Hot rodding is all about making machines work better. Often, it's also about ensuring that the little things work right. For example, on billet-steel roller cams it's common knowledge you need a "bronze" distributor gear. This softer material is more compatible with the steel camshaft gear. However, when combined with a high-volume oil pump, excessive wear on both the distributor gear and the cam gear will result. Distributor gears are relatively easy to replace, but if the cam gear suffers excessive wear, the only fix is a new camshaft, which is expensive and time consuming.
Crane Cams has come up with a great no-cost solution to this problem for the small-block, big-block and 90-degree V6 Chevy engine families. Crane recommends filing or cutting a .030-inch-wide by .030-inch-deep groove in the lower ring of the distributor housing immediately above the distributor gear. This slot is cut into a ring that seals a main oil passage, creating a spray of oil that is directed onto the distributor and cam gears for extra lubrication. The stock small-block system relies on splash oiling, which may not be effective at low engine speeds, especially when combined with a high-volume oil pump. The slot can be cut with a three-corner file or a Dremel tool. This slot must be positioned to face the camshaft drive gear. Position the distributor for proper initial timing, then use this position to determine the correct location to machine the groove so it faces the cam gear.
This is also an excellent idea for cams with flat-tappet cast-iron gears, especially when combined with a high-volume, high-pressure oil pump. According to Crane, high-volume pumps create additional load when operated at low speeds on engines with stock bearing clearances. These tighter clearances create a backpressure because the greater oil volume cannot escape past the bearings quickly enough. This additional load impacts the distributor gear because it also drives the oil pump.
This simple modification won't make more horsepower or impress the troops at the local drive-in, but if it keeps your engine running longer, it's worth doing.
