The engine frame, code D51101-07.0, serves as the main load-bearing structure of the MAN L21/31 engine, supporting the crankcase, cylinders, and auxiliary systems. Engineered for exceptional strength and stiffness, it distributes mechanical loads evenly across the engine and absorbs dynamic forces generated during operation. The robust design of the frame is critical for maintaining engine geometry, reducing structural fatigue, and ensuring stable performance during continuous heavy-duty service in marine and industrial environments.