Heads & Valve Train components control gas exchange within the engine’s cylinders, positioned directly above the engine block. Cylinder heads house valves, valve springs, and often the camshaft(s), facilitating precise intake and exhaust timing. Variable valve timing (VVT) systems, increasingly common, utilize hydraulic or electric actuators to adjust valve duration and lift for optimized performance and efficiency. Components are manufactured from high-strength alloys – typically aluminum for heads, and hardened steel for valve train elements – to withstand extreme temperatures and mechanical stress. Proper function relies on precise clearances, accurate timing, and effective sealing to maintain compression and prevent lubricant contamination.