The camshaft bearings supports the camshaft in the engine and allow for its rotation. Typically, an engine has between 1 and 7 bearings per camshaft, but it depends on your engine type. For a long time, most camshaft bearings were made of babbitt, a lead-based material that is quite soft and slippery. Now it is made of an aluminum alloy that is much stronger. It has some trade-offs, though, as the alloy is much less forgiving than babbitt and needs to be monitored more closely.