The importance of torsional vibration dampers
Torsional vibration dampers (TVD) or harmonic balancers perform vital roles in accessory belt drive systems (ABDS).
They help to:
- Prevent failure of the crankshaft caused by fatigue
- Decrease wear and tear on the belt, tensioner and other drive system components
- Improve noise, vibration and harshness (NVH) characteristics
When to change torsional vibration dampers
A torsional vibration damper that is worn out cannot properly dampen vibrations. If the vibrations are not controlled, the crankshaft can be compromised, hence the importance of checking the torsional vibration damper at each service interval
The following guidelines will help you to remove and install a harmonic balancer in 8 easy steps. Note that these are general guidelines. Before attempting to install any torsional vibration damper, always refer to the vehicle manufacturer’s recommended procedures for replacement and maintenance.
How to replace a torsional vibration damper in 8 easy steps
Draw a sketch or take a picture of the belt routing.
Unload the belt from the tensioner by rotating the tensioner.
Remove the torsional vibration damper from the crankshaft by fixating it and loosening the mounting bolts.
For TVDs that are fitted with one central expansion bolt it is necessary to block the flywheel. With every replacement the expansion bolt must also be replaced since it cannot be reused.
TVDs that are fitted with more than one mounting bolt can be replaced without having to block the flywheel. In that case, simply hold the TVD. These regular mounting bolts could be reused but it is not advisable to do so since in most cases they are damaged when removing the old TVD from the engine. That is why Gates includes all the bolts in the TVD packaging of its most popular TVDs.
Place the new TVD on the engine.
Torque the mounting bolts to 1/3 of the installation torque (in a star pattern in cases where TVDs are fitted with more than one mounting bolt).
Retighten the bolts to 2/3 torque, then tighten to full torque as specified by the vehicle manufacturer.
Inspect the drive system for wear. Install a new auxiliary belt and make sure the tensioner and overrunning alternator pulley are in perfect condition. Gates recommends the installation of a belt kit as part of a drive system overhaul.
NEVER start the engine without the belt fitted. To do so might cause damage to the newly installed TVD.
Load the belt on to the tensioner by rotating the tensioner to its correct position.
Installer notes: Beware fake pulleys with no damping function. They often have a rubber O-ring on the outside, with no rubber element inside!