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The main bearing cap, code 102985, is a precision-machined structural component that securely retains the main bearing shells and supports the crankshaft within the MAN L21/31 engine. Working together with the cylinder crankcase and tie rods, the bearing cap maintains accurate crankshaft alignment while distributing high mechanical loads generated during engine operation. Manufactured from high-strength materials and engineered to strict dimensional tolerances, it is capable of withstanding continuous vibration, cyclic loading, and elevated operating temperatures. Correct installation and tightening of the main bearing cap are essential for maintaining bearing integrity, minimizing friction and wear, and ensuring the long-term reliability and efficiency of the engine.

The cylinder crankcase, code 302938, is one of the primary structural assemblies of the MAN L21/31 engine, forming the foundation that supports the cylinder units, crankshaft, main bearings, and associated mechanical components. Designed to withstand substantial combustion forces, dynamic loads, and thermal stresses, the crankcase maintains the precise alignment of major engine components while protecting the internal mechanisms from external contamination. Manufactured from high-strength cast materials with excellent rigidity and durability, it also incorporates internal passages and mounting interfaces required for lubrication, cooling, and maintenance operations. Its robust construction is fundamental to engine stability, long service life, and dependable performance in demanding marine and industrial applications.

The measuring points, code 300715, are designated reference locations on the MAN L21/31 engine used for accurate inspection, maintenance, and condition monitoring. These points enable technicians to measure critical parameters such as dimensions, wear, alignment, pressure, temperature, and clearances in accordance with the engine manufacturer’s maintenance procedures. Proper use of the measuring points ensures consistent diagnostics, early detection of component wear, and precise evaluation of engine condition during inspections and overhauls. By supporting standardized maintenance practices and reliable performance assessment, the measuring points contribute significantly to operational safety, predictive maintenance, and the long-term reliability of the engine

The SERTO screwed connection K 70009 is a specialized connection fitting designed for leak pipe K 70006 in the fuel transfer pump system of the Sulzer ZV40/48 engine. Its main function is to establish a secure, pressure-resistant, and leak-free connection between the leak pipe and fuel system components, ensuring reliable leakage monitoring and controlled fuel drainage. Engineered from high-strength, corrosion-resistant materials compatible with diesel fuel applications, the fitting is capable of withstanding vibration, thermal cycling, and continuous mechanical loading. Precision manufacturing provides accurate thread engagement and reliable sealing throughout prolonged service intervals. By maintaining the integrity of the fuel leakage monitoring system, the K 70009 SERTO screwed connection contributes to improved operational safety, environmental protection, preventive maintenance, and dependable long-term engine performance.

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