Cylindrical pins with code EN1P1228 are essential alignment components used throughout the MAN L21/31 engine to ensure precise positioning of parts such as bearing caps, housings, and covers. Made from hardened steel, these pins provide high shear strength and wear resistance, allowing for accurate assembly and repeatable reassembly during maintenance. Their role is vital in preserving geometric accuracy, preventing misalignment, and maintaining the overall mechanical stability of the engine.