Fluidampr 830121 Harmonic Balancer for 2011-2016 GM 6.6L Duramax LML/LGH

Vehicle Fitment

• 2011-2016 Chevrolet / GMC 6.6 L Duramax V8 Diesel - LML / LGH engines
• Applicable to Silverado 2500HD, 3500HD; Sierra 2500HD, 3500HD; Express / Savana vans; and other GM 3/4-ton & 1-ton chassis using the 6.6 L LML/LGH Duramax

Features

• Viscous damper design - controls harmful crankshaft torsional vibrations across the full RPM range
• Precision CNC-machined, computer-balanced steel housing for smooth, vibration-free operation
• Externally balanced - suitable for stock and modified diesel engines
• Durable black zinc-coated finish for corrosion resistance and long service life
• Engraved timing/degree markings for accurate ignition and timing reference
• SFI 18.1 certified - built to meet performance and competition standards
• No maintenance or tuning required - sealed design maintains damping across engine life
• Reduces stress on crankshaft, main bearings, and timing components - ideal for heavy loads, towing, or high-torque applications

Specifications

• Outside Diameter (OD): 8-3/8" (8.375")
• Bore Diameter: 1.9300"
• Overall Length / Depth: 2.858"
• Rotating Weight: approx. 16.0 lb; Total Weight: approx. 24.0 lb
• Engine Balance: External balance
• Material: High-grade steel damper housing
• Finish: Black zinc chromate coating for corrosion resistance
• Keyway: Single 5 mm crank keyway - matches stock crankshaft key slot
• Safety / Performance Rating: SFI 18.1 certified
• Position: Front crankshaft pulley / harmonic balancer

Included Components

• 1x Fluidampr 830121 Performance Diesel Series Harmonic Balancer
• 1x Timing mark washer (for proper installation alignment)

Product Description

The Fluidampr 830121 is a heavy-duty viscous harmonic balancer engineered specifically for 2011-2016 GM / Chevy / GMC 6.6 L Duramax LML and LGH diesel engines. Unlike stock elastomer-style dampers that degrade over time and lose effectiveness, the 830121 uses a sealed, fluid-coupled internal mechanism to continuously absorb and dissipate destructive crankshaft torsional vibrations across the entire RPM range. This results in smoother engine operation, reduced risk of crank or bearing failure, and improved overall engine longevity - especially under heavy load, towing, or high-torque conditions.

CNC-machined, computer-balanced components and a robust steel housing with corrosion-resistant coating ensure that this balancer can withstand years of abuse in demanding diesel applications. With an 8.375" outside diameter, precise 1.930" bore, and externally balanced design, the 830121 is a direct, bolt-on replacement for the factory damper on LML/LGH engines - making installation straightforward. Its SFI 18.1 certification means it's trusted for both street and performance use. Whether you're building a heavy-duty tow rig, a performance diesel, or simply replacing a worn or failed stock damper - the Fluidampr 830121 delivers reliable, maintenance-free vibration control and engine protection for the life of your truck.