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Message: <blockquote data-quote="hulkv6tt" data-source="post: 1063432002" data-attributes="member: 78589">Guys, i was offered a full set of lighten pulley yesterday,....but my concern is "harmonic vibration" that can coz a huge RM later in the future....con rod sleeves, crank shaft bearing...etc.my question ...how true is it? any of you guys out there alraedy using it?....i know basically it will improve our acceration just like a lighten flywheel kinda improvement....just need your expert/experience opinion....Thanks in advance :hmmmm:---------- Post added at 10:32 PM ---------- 6 hour anti-bump limit - Previous post was at 10:17 PM ----------this is the info that make me think twice....A harmonic balancer (also called crank pulley damper, crankshaft damper, torsional damper, or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration and serves as a pulley for drive belts.Every time the cylinders fire, torque is imparted to the crankshaft. The crankshaft deflects under this torque, which sets up vibrations when the torque is released. At certain engine speeds the torques imparted by the cylinders are in synch with the vibrations in the crankshaft, which results in a phenomenon called resonance. This resonance causes stress beyond what the crankshaft can withstand, resulting in crankshaft failure.To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The damper is composed of two elements: a mass and an energy dissipating element. The mass resists the acceleration of the vibration and the energy dissipating (rubber/clutch/fluid) element absorbs the vibrations.Additionally the energy transferred from the piston to the crankshaft can induce as much as 2 degrees of twist in the crankshaft, which has many follow-on effects on all engine elements that require adequate timing such as valve opening, cam timing, ignition timing etc.Over time, the energy dissipating (rubber/clutch/fluid) element can deteriorate from age, heat, cold, or exposure to oil or chemicals. Unless rebuilt or replaced, this can cause the crankshaft to develop cracks, resulting in crankshaft failure.Performance enthusiasts have been known to remove harmonic balancers, usually when the balancer is attached to the crank pulley, deciding that they aren't necessary and their mass reduces the performance of the engine. However, this is unproven and potentially very risky because the danger of damage to the engine from the vibrations the damper is intended to prevent is too high.Certain cars, however, do not come equipped with an external balancer on the crank pulley, and as such, can have the pulley replaced with a performance oriented product which counter-acts these resonance frequencies.---------- Post added at 11:35 PM ---------- 6 hour anti-bump limit - Previous post was at 10:32 PM ----------it's a NO! NO! ...for meAlthough an aspect of vehicles that 95 per cent of the car community knows nothing about, you’ll find a harmonic balancer mated to the bulk of modern day metal rolling around our streets. A harmonic balancer, also commonly referred to as a crank pulley damper, a torsional damper or a vibration damper, is a nice lump of metal that connects to the crankshaft. The damper aids in reducing the torsional vibration that your engine experiences on a daily basis.Each time an engine fires into life and the cylinders tick over, torque heads the way of the crankshaft. And every time torque is applied then removed from the crankshaft, vibrations form. These vibrations resonate through all of the components in the engine block. At certain engine speeds the vibrations, when joined with the torque forced upon them, can form what’s known as resonance. If strong enough, this resonating energy can be an inherent risk to the well-being of the crankshaft. And the last thing you want is to damage your car’s main rotating assembly, right?Many vehicle manufacturers fit a device to overcome this problem. That’s where the harmonic balancer comes into play. The idea behind the harmonic balancer is to suppress and then absorb any excessive resonance and vibration experienced by the crankshaft. Its role is to then dissipate vibrations safely to avoid crankshaft damage. In most cases the internal section of a harmonic balancer is constructed from a rubber-like material, and the unit can be found fitted up to the end of the crankshaft, behind the crank pulley.Some argue that the addition of a lightweight harmonic balancer not only aids engine longevity, it can also increase acceleration. However, many people opt to remove the harmonic balancer from their cars in a bid to aid performance, since the large, heavy unit can sometimes affect motor performance. It’s not an uncommon practice, but it can lead to premature damage to the crankshaft. So if you’re thinking of removing the balancer, be sure to seek professional advice first.</blockquote>