What opens and closes valves in an ohv?

A pushrod opens and closes valves in an OHV (overhead valve) engine. The pushrod is a metal rod that is located between the camshaft and the rocker arm. When the camshaft rotates, it pushes the pushrod, which in turn pushes the rocker arm. The rocker arm then opens the valve, allowing air and fuel to enter the cylinder or exhaust gases to exit the cylinder.