Valve rods and rockers are critical components of an engine’s valve train, translating rotational motion of the camshaft into linear motion to open and close intake and exhaust valves. Rocker arms pivot on a fulcrum, amplifying camshaft lift and transferring it to the valve stem via the valve rod (or pushrod in OHV engines). These components are located within the cylinder head and engine block, operating in a high-temperature, high-stress environment. Manufacturing typically utilizes hardened steel alloys for durability and resistance to wear. Precise machining and heat treatment are essential for maintaining valve timing and engine performance. Variations include roller rockers to reduce friction and different length pushrods to accommodate aftermarket camshafts.