The camshaft is the part where the valves of an internal combustion engine are operated. There are different forms in which a camshaft is used, such as, for example, bottom or top. But there are also engines with a double camshaft. It is useful to know that nowadays almost only overhead camshafts are used. In this variant, the valves are controlled by hydraulic valve lifters or rocker arms.
When there is a tick in the engine, this can be due to wear in the camshaft, although often contamination of the hydraulic valve lifters can also be a cause.