What is the significance of the crankshaft balancer in a heavy-duty marine engine?

• A. Increases engine torque
• B. Reduces torsional vibration and mechanical stress
• C. Improves cooling efficiency
• D. Alters fuel injection timing

Answer: (B)

The crankshaft balancer, often called a harmonic damper, targets torsional vibrations in the crankshaft. In heavy‑duty marine engines with long crankshafts, the firing pulses cause twisting forces that travel along the shaft. If these torsional waves grow, they put repetitive stress on the crankshaft, bearings, and gear train, potentially leading to fatigue and damage. The balancer adds a mass and damping mechanism that absorbs and dissipates energy at the resonant frequencies, smoothing the rotation and keeping the crankshaft from experiencing large torsional amplitudes. That yields a quieter, smoother engine with less mechanical stress and longer component life. It doesn’t increase torque, improve cooling, or change fuel injection timing.