Cylindrical pins with code EN1P1228 are essential alignment and locating elements used throughout the MAN L21/31 engine assembly. These precision-machined pins ensure accurate positioning of components such as bearing caps, housings, covers, and structural parts during assembly and maintenance. Made from hardened steel, they provide high shear strength and excellent wear resistance, enabling repeatable disassembly and reassembly without loss of alignment. Their role is critical for maintaining geometric accuracy, minimizing stress concentrations, and supporting the long-term mechanical stability of the engine.