The Engine Heads & Valve Train category contains critical components for controlling the flow of air and fuel into the engine and the expulsion of exhaust gases. These parts are located within the engine cylinder head assembly of passenger cars and commercial vehicles, and are essential for proper combustion and engine performance. Key components include cylinder heads, valves, valve springs, camshafts, rocker arms, and lifters. For example, MAN MPN 81473016067 is a cylinder head for specific truck models, while MPN 51055040122 represents a valve component. Maintaining a healthy valve train is vital for engine efficiency, power output, and longevity, and replacement parts ensure correct operation. This category also includes related sealing and mounting hardware specific to these engine systems - such as those found in MAN parts 81274210293 and 81018106015.