BILLET CAMS

Most camshafts are produced from chill-cast iron. This process involves casting the blanks in a rough camshaft-like shape, meaning the cam profiles and bearings are ground onto the cast lobes. This is by far the most cost-effective method of producing camshafts in large volume, which is why almost all factory and mass-produced aftermarket performance cams are made this way.

For one-offs and high-end motorsport applications, however, camshafts are often made from steel billet. The result is a much stronger, hardwearing cam.

Billet cams are super-strong because, as the name suggests, they’re made from a single piece of billet steel. Starting out as a round bar, the material is then turned down to the required size to suit the expected bearings and fixings. Cam lobes are left circular to begin with, before being ground into a shape on a computer-controlled stone grind wheel. The cams are then heat-treated and case-hardened to prevent wear.

Additionally, billet cams allow for gun-drilled centres. This helps reduce weight, but also allows for the centre of the cam to be used as an oil channel with cross-drilled holes feeding the lobes or bearings.

Billet cams are best suited to high-revving applications, but the expense involved in producing them means they’re almost always only found in professional motorsport environments.