Parts Inventory > Silicone viscous Crank Dampers and Mercury Filled Crank Balancers > Pittsburgh Power > Inspection Sheet 


When to replace your stock damper....

The tell-tale signs your stock damper is going bad.

  • Bulged or Raised Cover (Protruding Sealant)
  • Heat build-up due to other components rubbing on damper
  • Fluid leakage from damper around the cover seams or filler plugs
  • Failure or excessive wear of crank, bearings or other rotating components.
  • Thrown or slapping belts
  • Rattling sound coming from damper
  • Dents or damage on damper.

The Problem: Torsional Vibration

Each time the air fuel mixture inside a cylinder is ignited, the combustion that results creates a torque spike - an extremely rapid rise in cylinder pressure. This pressure is applied to the top of the piston, which becomes the force that is applied to the crankshaft through the connecting rod. Each torque spike is like a hemmer blow. It hits with enough intensity that it not only causes the crankshaft to turn , it actually deflects, or twists the crankshaft ahead of its rotation. This twisting acting and rebound is known as torsional vibration.

Unchecked torsional vibrations can cause:

  • Crankshaft Cracking or Failure
  • Excessive Bearing Wear
  • Excessive Gear Wear or Failure
  • Broken Accessory Drives
  • Thrown or Slapping of Belts

Vibratech TVD's Viscous Torsional Vibration Damper

The Vibratech TVD viscous damper is a simple design consisting of a free rotating inertia ring surrounded by a high viscosity silicone fluid enclosed in a totaly sealed leakproof housing.

When crankshaft torsional vibrations occur, the outter hiusing of the damper eacts with the crankshaft, twisting while it rotates, while the inertia ring inside moves out of the phase with the housing. This relative motion between the inertia ring and the housing causes the inertia ring to shear the silicone fluid, which reduces the vibration.

Viscous Damper Inspaction and Replacement

The nature of silicone fluid results in a high energy dissipation, which makes it an excelent damping medium. However, over extended periods of time under heavy duty operation, the damper may waer out, resulting in the need to replace it.

A worn out viscuos damaper leaves crankshaft torsional vibration unchecked and can cause costly engine damage. That why regular damper replacement is critical to longer engine life. While recommended replacement intervals may vary, the average is about 500,000 miles (15,000 hours) or at major engine overhauls and in-frame rebuilds, regardless of condition.

Dampers that utilize rubber or elastomer rings to dampen vibrations are prone to deterioration that may destroy engine components in as little as 1 to 3 years. Rubber damper rings dry out and crack over time, reducing the effectiveness of the damper. Exposure to oils and solvents can cuase rubber damper rings to swell and quickly breakdown. These changes in durometer, overtime, will cause damper failure and damage to costly engine components.