See full version: What is a Harmonic Balancer? Complete Guide 2021
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.
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). here
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. [links]
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 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. here
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. more
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. more
Harmonic Balancer Puller and Installation here
But consider for a second the forces that are acting on the crankshaft -- they're tremendous. Each time a cylinder fires, a force acts upon the crankshaft, causing it to twist. But this force also causes vibrations in the crankshaft, and at certain frequencies, the shaft can resonate, which makes the vibrations even worse [source: Mach V].
However, the rubber material can deteriorate over time. So if your harmonic balancer is going bad, you could get rough engine vibrations, a cracked crankshaft, or even a serpentine belt that gets thrown off its track. Replacing one is excellent preventative maintenance, and that's exactly what we'll talk about next. here
Every engine is different, so if you want to change the harmonic balancer on your car, you'll need to search around various car forums and Web sites to see how it's done on your specific model. Generally, you'll want to remove the belt from the crankshaft pulley and then take the harmonic balancer mounting bolt off with a socket and ratchet. From there, you'll use the puller tool you just bought to take the balancer itself off the crankshaft [source: Auto MD].
First, you'll probably need to go out and buy a tool you might not have -- a harmonic balancer puller. That's a specialized tool that's used to safely remove harmonic balancers without damaging your vehicle, and it also works on things like gear pulleys and steering wheels. Search around to find the right puller for your needs. They're usually around $25 or so.
Orefice added, “[In many classes], racers are required to have an SFI-approved harmonic balancer to participate in sanctioned drag racing. Performance parts and power adders change the harmonics of the engine. Factory balancers come tuned to a specific frequency. Once you change your engine’s harmonics, the factory balancer is no longer doing its job. Drag cars have complete custom-built engines, there is no OE damper that will properly protect their engine.”
We were also curious about the effects on a supercharged engine because there is extra load from the drive belt. “On older Roots-style superchargers when using a rubber cogged belt, it is still somewhat common to run without a damper,” said Rose. “The constant drag of the supercharger along with the rubber belt stretching helped to dampen the engine. However, with today’s more efficient superchargers (screw, centrifugal, etc.), the new technology belts (Kevlar, composite, serpentine, etc.), and newer engines with lighter-duty parts inside them, the use of a harmonic damper is highly recommended. A harmonic damper will help to protect that expensive engine against those harmonics and should help reduce or eliminate the change of failure from those same harmonics.” more
A V-8 fires every 90 degrees of crankshaft rotation, so the power is applied in short, continuous bursts. And while your engine provides continuous power through the rpm range, it’s actually a series of power pulses that keeps the crank moving. For example, imagine pedaling a bicycle briskly. In this case, you’ll be applying maximum force for only a short period (in degrees of crankshaft rotation) as you push past TDC, however, the power seems to be applied seamlessly. Now, imagine your legs firing as pistons rather than the smooth flow of a human pedaling.
As you can imagine, the force within a race engine is far greater than what you can generate with your legs, and at times, it’s much more abrupt. Because of this extreme force, the crankshaft is subject to torsional deflection. This twisting, followed by the metal rebounding, causes harmonics, even on robust aftermarket crankshafts. here