What is a Harmonic Balancer? Complete Guide 2023

What is a harmonic balancer, and what does it do?

A harmonic balancer is an essential part of your engine. Contrary to what the name sounds like, a harmonic balancer does not balance your engine literally. Instead, it removes and absorbs unwanted vibrations. This vibration it absorbs comes from the torsional twisting of your engine's crankshaft. This balancer is simply a circular device made of rubber and steel. It is located and bolted at the front end of your engine's crankshaft, absorbing vibrations.

Harmonic balancers are often called dampeners, and in truth, they are dampeners in their effect. In operation, Dampeners are similar to a torsional shock absorber, which helps prevent vibration from the engine and dampen torsional twist. This torsional vibration (or twisting vibration) emanating from the engine is a product of the firing pulses produced from each combustion event.

The force the combustion process produces makes the crank deflect to a certain extent in the force's direction. When this force goes away, the crank springs back slightly. In some scenarios, the crank may resonate and, in turn, make the vibration worse. As the cylinders in your engine fire, they move upward and downward.

They generate the torque that gets transferred to the crankshaft. It is common knowledge that the crankshaft is responsible for converting the engine's power into a rotational movement that pioneers the turning motion of the wheels of a car exhibits. Have it in mind that with the eight cylinders in the engine firing, these forces are constantly interacting with each other, moving back and forth. Nonetheless, all of its effects dissipate because of the presence and operation of the harmonic dampener.

Crankshaft function

External Balancing

The harmonic balancer has a unique function in some engines. This function is to aid in the engine balancing strategy. Additional weights are attached to the harmonic balancer that helps offset the rods and pistons' existing weights. This process of adding weights to the harmonic balancer is known as External Balancing. This external balancing feature is what differentiates a damper from a harmonic balancer.

Harmonic Balancer VS Harmonic Damper

A harmonic balancer is also known as a crankshaft damper, torsional damper, or vibration damper. However, the only difference the harmonic balance has with the harmonic damper is the counterweight the balancer has, helping it balance the rotating system.

When managing the torsional and resonance vibration from your crankshaft, the presence of a harmonic damper is crucial. We connect this device to the free or accessory drive end of your internal combustion engine's crankshaft.

Your harmonic balancer or damper must be an interference fit to the crankshaft. This feature will help the balancer to do its job correctly without restraint and hiccups. In other words, an interference fit means the harmonic damper will work in perfect step with the crankshaft.

Harmonic Balancer vs Harmonic Damper

An interference fit is suitable for v8 engines with cross-plane cranks or generally for engines with a long crankshaft. Typical examples of such engines include the straight-6 and straight-8 machines. The life span of your crankshaft is significantly dependent on the harmonic and torsional vibrations. These forces can lead to your crankshaft's instantaneous damage or failure if the crankshaft runs at or through an amplified resonance.

The balancer often uses a pulley for the accessory drive belts, which turns the alternator, water pump, and other crankshaft-driven devices.

The damper components

Damper components

Damper components

The damper comprises two key elements: an energy-dissipating element and an inertia mass. Dampers predominantly consist of rubber, a synthetic elastomer, a spring or fluid, and a clutch.The dissipating element is concerned principally with absorbing the harmonic vibrations. At the same time, the inertia mass deals with the torsional crank motions. Dampers must always be fit to perform these inhibiting tasks to work correctly.

Furthermore, dampers come with a specific weight (mass) and a particular diameter. The diameter and exact mass depend primarily on the damping method or material used to reduce the damp and crankshaft resonances.

During combustion

Pressure rises from within the combustion chamber. This pressure forces each piston to initiate a downward movement within the cylinder. With each stroke, a rotational force is created suddenly towards the crankshaft. The crankshaft may be a stout component, but it is not rigid. As a result, during these combustion processes, the crank twists a little in response to the applied pressure, which could run into thousands of pounds.

A crank twist is akin or similar to a simple torsion bar having a lever arm at one end. With this in mind, let's say you hit a lever arm with a hammer. There will presumably be a slight impact on the lever arm.

However, the lever arm will spring back into position and vibrate for a while before assuming a rest state. We can see that we both have a torsional twist that inadvertently births a torsional vibration. This vibration is visible during the spring back effect after an impact.

A torsional twist is a product of the thickness and part length (inline engines generally have a longer crankshaft than V-configurations), the material shear modulus (this is the material stiffness), and torque (from the combustion and crank throw force).In the same light, torsional vibration is also dependent on the torsional stiffness, part length, and the object's ability to withstand or resist torsion (known as moment of inertia).

In operation


Once the engine begins to run, harmonics produced by the combustion process begin to resonate through the engine's crank. In this situation, the harmonic balancer has one function to perform: dispense these harmonics immediately before it creates a bigger problem. The circular device here comprises of metal and rubber principally.

This device is attached to the crankshaft's front end to help absorb the vibrations. It usually connects to the crankshaft's pulley, responsible for driving other accessories like the air conditioner. The rubber component within the pulley absorbs the vibration.

This device keeps the vibration at a safe level and protects the crankshaft from damage. However, this rubber does not last forever; it deteriorates with time. As a result of the deterioration of this rubber, your harmonic balancer can go bad. A bad harmonic balancer with mean disturbing or violent engine vibrations cracks to your crankshaft, and you make also experience a fault on your serpentine belt if it gets thrown off track.

Types of Harmonic Balancers

There are three major types of harmonic balancers:

  • Elastomer

The elastomer damper comprises a ring of rubber installed between the outer inertia ring and the inner hub. The common complaint associated with the elastomer damper is the deterioration of the elastomer interface. As time progresses, the components get affected by age, temperature differences, oil exposure, and chemical exposure. You can observe with your optical eyes for signs such as bulging of the elastomer, separation or cracking or wobbling while running. Once you notice this, then it’s time for a change.

  • Fluid

The fluid damper has no elastomer present. In operation, it uses fluid to absorb flexing energy coming from the running engine. They are often associated with racing cars and are not really need in streetcars.

  • Friction balancers

Finally, the friction balancers or dampers rely on internal clutch discs to get rid of harmonics. it is the most adapted harmonic damper for race cars especially the all-aluminum clutch-style with 360-degree calibrations.

How to replace and install a Harmonic Balancer

how to install

how to install[/caption]Well, replacing and installing a harmonic balancer is both an easy task and a tedious one. For starters, installing a new harmonic balancer will hardly cause you to break a sweat. However, this process's flip side, or the tedious part, involves is removing the old harmonic balancer.

Removing the old harmonic balancer is a pretty much rigor task. This process will often demand that you remove your bumper or front fender, and sometimes you may need to remove your radiator. To do this, you must adequately equip yourself with the necessary tool for this exercise.

You may need to purchase if you do not have the tools. An example of such a tool you will have to buy is a harmonic balancer puller. A harmonic balancer puller is an essential tool that will help smoothen your process and make it somewhat seamless. This tool is also useful when dealing with gear pulleys and steering wheels.

A harmonic balancer puller is affordable and ranges around $25 in cost. However, take some time out to make sure you purchase the right puller for your device.

Removing old harmonic balancer

Every car comes with a different engine and most especially its orientation. Therefore, the process of removing and installing a harmonic balancer will be different for various car engines. We advise that you visit your manufacturer's website or another forum to note how to go about the process for your car specifically.

A general approach to installing a harmonic balancer

In a general sense, removing your harmonic balancer, you will have to take out the belt from the crankshaft pulley. After which, you will then remove the harmonic balancer mounting bolt off with a socket and ratchet. After removing them, you will need to use the harmonic balancer puller.

This tool that you have purchased will help you remove the harmonic balancer from the crankshaft. Installing a new harmonic balancer is pretty much the same procedure in reverse. It would be best to make sure the new balancer and the old one you intend to remove are the same. Take note of the bolt hole location and size. Remember to look carefully at the torque settings to avoid a mistake.

After installing, try to start your engine. If your engine starts without unusual vibrations going over the roof, then you have done a great job installing your new harmonic balancer.

Signs of a failing harmonic balancer

A harmonic balancer's failure can be a nightmare to not just the driver alone but passengers as well. Therefore, a driver must look out for these signs, which indicate a failing harmonic balancer. We have a well-written article on top signs of a bad harmonic balancer and how to fix it. Nonetheless, let us briefly look at some of the symptoms here.

Damper failure symptom

Damper failure symptom[/caption]

  • Noise from drive belts: this is a result of slipping drive belts or squealing drive belts. The noise emanating from the belt can also be a result of damage to the belt or prolonged belt wear.
  • Leaks from the front main seal: this leak occurs when the oil seal and the timing cover wear leak into the harmonic balancer's metallic component. Thereby allowing oil to slip off.
  • Poor engine performance: poor engine performance and irregular idle common with old engines with electronic ignition are typical with a faulty harmonic balancer.
  • Wobbling ring effect: you can see a visible wobbling caused by rubber failure of the inner hubs outer ring.
  • Rubber ring depletion: factors such as cold, dirt, heat, chemicals, and oil can affect the efficiency of the rubber ring. These factors are a result of engine harmonics. You can see the effect on the rubber ring between the inner hub and outer ring. The balancer hub and outer ring will also have visible cracks and warps.
  • Unusual engine vibration: rough vibrations than what you are conversant to may come from your engine as a warning sign of a faulty harmonic balancer. We only advise that it is wise to look at your balancer and your front-end accessory drive components when you notice excessive vibrations. If a fault is on your harmonic balancer, you must replace your vehicle's balancer with immediate effect.

Key Takeaways!

  • A harmonic balancer is a crucial part of your vehicle's engine, and the life span of your crankshaft depends on it.
  • The balancer has a principal function of the dampening effect on the vibrations coming from the engine. These vibrations emanating from the engine will be too much for the crankshaft to bear without a balancer.
  • A harmonic balancer or damper must be interference fit to the crankshaft. This feature will help your balancer to perform its job correctly without restraint and hiccups.
  • The signs of a failing harmonic balancer include an excessive vibration from your engine, a wobbling ring, rubber ring depletion, and poor engine performance. You'll also notice noise from the drive belts and leaks from the front main seal.
  • The process of replacing and reinstalling a harmonic balancer can be an easy task and a tedious one at the same time.

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