Vernier Pulleys

In order to ensure optimum performance it is essential that your camshafts open and close valves at the correct point in the engine operating cycle. This is referred to by most as cam timing.

At the least, incorrect cam timing will lose some bhp, at the worst valve/piston contact may occur. If a valve is damaged the best case will be an engine that runs very badly. The worst case is the valve head dropping into the cylinder at high revs and destroying the engine.

To accurately set your cam timing, we offer vernier cam pulleys. These pulleys feature a central hub onto which the outer toothed pulley wheel is bolted. The hub bolts onto the camshaft as normal. By slackening the pulley bolts, the relationship of tooth position to camshaft is variable, enabling cam timing to be accurately set.

We suggest cam timing be accurately checked even on standard engines and corrected by vernier pulleys if more than a degree or two out. These pulleys come as standard in most of our engine upgrade kits.