Chevy Small Block - Secrets Of The Cheap Hydraulic Roller Lifters

With a boneyard full of engines to choose from, here's an easy way to tell a good lifter from a bad one. Inspect the roller wheel for any kind of pitting or excessive wear. Clean the lifter in solvent, lube it lightly with engine oil, and run the lifter up and down the inside of your forearm. If you feel any rough or tight spots, choose another lifter.

The small-block Chevy hydraulic roller cam blocks come equipped with this factory cam retainer plate. Chevy used two different designs, an early-model wide-bolt spread (3.620 inches) and a later-model narrow-bolt spread (3.294 inches). We've included both part numbers in the Chevy parts list chart on page 60.

If you're using a one-piece rear main seal truck block that was configured for a flat-tappet cam, there are three cast-in stands in the lifter valley (arrows) that may need to be drilled and tapped. Use the stamped-steel spider to position the holes, then drill and tap the holes. If the engine is assembled, mask off the open areas in the valley to prevent spreading iron shavings into the engine.

Factory roller cams require what GM calls a melonized distributor gear to prevent wear. Most aftermarket street hydraulic and mechanical roller cams now come with an iron gear pressed on the end of the camshaft that allows the use of a standard iron distributor gear. In the photo, you can see how the material changes at the rear of the cam for the iron distributor gear and rear cam journal.

All camshafts create greater lobe lift by reducing the diameter of the lobe's base circle. A smaller base circle can allow a stock GM hydraulic roller lifter to drop down enough to lose connection with the steel retainer. When this happens, the lifter spins in its bore and instantly kills the camshaft.

It's important to check a performance cam in the block to ensure that the lifter guides remain perfectly flat on the tops of the lifter bores throughout the entire lift curve. If excessive lift moves the guides upward, then the cam base circle is incorrect and must be changed to prevent engine damage. Also make sure to place the lifter guide so you can read the "up" stamped into the guide.

All camshafts create greater lobe lift by reducing the diameter of the lobe's base circle. A smaller base circle can allow a stock GM hydraulic roller lifter to drop down enough to lose connection with the steel retainer. When this happens, the lifter spins in its bore and instantly kills the camshaft.

Adding a hydraulic roller camshaft also changes the requirement for the distributor gear. Most street roller cams come with iron distributor drive gears, but if not, then a different distributor gear is required. Crane offers a coated steel distributor gear that is compatible with either the steel or induction-hardened cam cores. Before this new line of gears, the old solution was a softer copper alloy (aluminum-bronze) gear (center), which tended to wear quickly on street-driven engines.