Product Descreiption
1. Basic Parameters
- Part Number: 3925568-QSC (also referenced as 3925568)
- Engine Fitment: Cummins QSC8.3 / 6CT8.3 diesel engine
- Type: Rubber tuned torsional vibration damper (harmonic balancer)
- Construction:
- Inner hub: Metal, interference-fit to crankshaft
- Elastomer layer: High-damping rubber (nitrile/EPDM)
- Outer inertia ring: Heavy steel mass
- Dimensions (typical):
- Diameter: ~220–240 mm
- Thickness: ~35–45 mm
- Weight: ~12–15 kg
- Natural Frequency: Tuned to 1st–2nd order crankshaft torsional resonance of QSC8.3
2. Installation Position
- Location: Front end of the crankshaft (free end, opposite the flywheel/transmission)
- Mounting:
- Press-fit or bolted to the crankshaft nose
- Positioned in front of the timing cover and behind the accessory drive pulley (water pump/alternator belt pulley)
- Orientation: Installed with timing marks aligned for ignition/camshaft timing
3. Function
- Primary Function: Reduce crankshaft torsional vibration and suppress harmonic resonance
- Key Benefits:
- Protects crankshaft: Eliminates resonant stress peaks to prevent fatigue cracking or catastrophic failure
- Extends component life: Reduces vibration transfer to timing gears, bearings, front seals, and accessory drives
- Improves NVH: Lowers engine noise and vibration for smoother operation
- Maintains timing accuracy: Prevents torsional deflection from disrupting camshaft/crankshaft synchronization
