The fitted bolt, marked with code number K 31024, is a specialized fastener used in the crankshaft assembly of the Adriadiesel/Jugoturbina/Zgoda/Sulzer ZV40/48 diesel engine. Unlike standard bolts, fitted bolts are machined for an exact fit within the crankshaft’s mounting holes, providing enhanced shear strength and precise alignment. This ensures minimal play and maximum structural integrity, especially important under the intense loads and rotational forces present in large diesel engines. The fitted bolt is crucial for maintaining crankshaft geometry and operational reliability, supporting the engine’s performance and durability across prolonged use.