Harmonic Dampener Diagnostics -

Harmonic Dampener Diagnostics

Every time a cylinder fires, the crankshaft speeds up a very small amount for a short period of time. It is then slowed down as the next cylinder in the firing order compresses air and fuel for the next combustion event.

Harmonic-dampener-marauder4.6LV8 harmonic-dampener

Every time a cylinder fires, the crankshaft speeds up a very small amount for a short period of time. It is then slowed down as the next cylinder in the firing order compresses air and fuel for the next combustion event.

The speeding up and slowing down of the crankshaft produces torsional vibration or twisting force, which can put stress on the crankshaft and the connected components. If the stress is great enough, the crankshaft will eventually fail.

Adding mass to the crankshaft assembly is one solution for minimizing vibrations in some engines, but this approach increases rotating mass of the crank and overall weight of the vehicle. The other cure is a crankshaft pulley with a harmonic dampener/balancer.

A harmonic balancer is like a punching bag for the crankshaft. There are two basic components in a harmonic balancer: inertial mass and an energy-dissipating element. The inertial mass consists of an outer ring that could have the grooves for the belts and an inner hub that connects to the crankshaft. The outer ring contains the mass to cancel out the vibrational forces.

Between the two metal components is the energy-dissipating element, which is a rubber or elastomeric compound. This ring of rubber can cause the two metal parts to go out of phase as much as 1º to 2º as it absorbs the vibrations in the crankshaft. When the energy-dissipating element flexes, it changes the motion into heat.

On the surface, a harmonic dampener may seem simple, but tuning the unit to an engine over a specific range of rpms is complicated engineering.

 

For more on harmonic dampeners, click here and here.

You May Also Like

Diagnostic Procedures For Stop/Start Systems

Stop/start technology is more than just a switch wired to the brake pedal and starter.

When trying to resolve a complaint, code or no-start/no-crank condition on a stop/start vehicle, it is essential to know how the system operates. The problem may not have a complicated reason – something simple may be causing the stop/start system not to work.

The greatest obstacle to the advancement of stop/start technology is the driver’s and technician’s lack of trust in and knowledge of the technology. Many older drivers and technicians fear that stopping and starting the engine will cause a shorter life for the battery, starter and engine. But the real fear is that the engine will not start again at a green light. 

Brake Pad Wear Sensors

Brake pad wear sensors have been around for years and continue to evolve.

Topology and Your Scan Tool

Topology influences how you access the modules with your scan tool.

Ride Control Diagnostics From Tire Wear Clues

Learning how to read the tire and communicate your findings is the key to ride control service.

Understanding Engine Timing- Chains, Gears and Belts

Engine timing is critical for overall performance.

Other Posts

Air Filters and Fuel Trims

Modern engines rely on precise airflow and oxygen sensor data for optimal performance.

Mercedes Ignition Coil Pack Diagnostics

Replacing a single coil might not be the best approach to curing an engine of a chronic misfire.

Understanding Fuel Injection

Though many different terms have been used for the technology, it really just comes down to indirect or direct.

Brake Line Replacement Options

We’ve got all the rules for replacing brake lines for you right here.