Valves control the flow of air/fuel mixture into and exhaust gases out of the engine cylinders. Typically constructed from high-strength alloys like steel or titanium, valves feature precisely machined faces and stems for sealing against valve seats and guides. Pushrods are precision rods transferring motion from the camshaft to the valves in engines utilizing a non-overhead cam design. They must withstand significant compressive loads and operate within tight tolerances to maintain valve timing and engine performance. Valve springs maintain valve closure, while retainers and keepers secure valve components during high-RPM operation. Proper function is critical for maintaining engine compression, efficient combustion, and overall engine health.