The counterweight, bearing code number K 31020, is a critical component of the crankshaft system in the Adriadiesel/Jugoturbina/Zgoda/Sulzer ZV40/48 diesel engine. Its primary role is to balance the rotating mass of the crankshaft, reducing vibrations and mechanical stress during engine operation. By offsetting the reciprocating forces of the pistons and connecting rods, the counterweight contributes to smoother rotation, improved engine efficiency, and prolonged component life. Manufactured to precise tolerances and from high-strength materials, this counterweight ensures stable performance even under the engine’s most demanding load conditions.