Jcapp3078

After researching pulley systems for over three months now, I have completely blown my mind with all of the information. I spoke to ASP Racing, Renntech, and Klemmann. One area of concern that was mentioned by Renntech was the harmonic balancing of the new pulley. It was explained to me as follows: the Renntech pulley is a two piece system similiar to the pulley that is on the vehicle. I was told my the sales rep. that without a harmonic balancer the pulley would eventually cause problems. However, when talking to ASP Racing. He explained to me how their system deals with this. He stated that the lighter alloy and the belts help deal with the harmonics--I guess that wouls hold true for the Klemmann since they are similiar. Can anyone shed some light to a laymen on theses terms, and there ultimate influence on engine an kompressor failure.

mdp c230k

A harmonic balancer absorbs vibration usually within the rubber coupling between its two sections. A harmonically balanced engine has been adjusted by removing material from its parts to create a rotationally balanced system. A balancer is a mass production solution to true balancing which must be done on every engine and is very time consuming. This is why Ferraris are such smooth engines. A balanced engine will make more power and rev higher and last longer.

young

i don't understand exactly how important the harmonic damper/balancer is either.

i was told that dinan had written a paper on the importance of maintaining the harmonic damper/balancer but i could not find that reference. w/out a long term study on the engine, who knows?

Buellwinkle

I think there's some misinformation floating around. A harmonic balancer is a mechanical device with counter weights inside that pulse in opposition to the pulses of the engine to make it not vibrate as much. I had harmonic balancer put in my Harley to reduce engine vibrations for comfort. These were common on V8's to reduce vibration.

What the factory pulley has is a rubber like damper. It's basically a groove cut into it that you can see from the back and is filled with some kind of flexible material (maybe rubber or a synthetic rubber, I don't know). I took pics of it before and posted it but it's hard to see the black rubber on a black pulley. Check my install instruction for the rear view picture of the pulleys. The slighly uneven ring of rubber can be seen there. What I've been told that it's to dampen vibrations from the pulleys and belts to the crankshaft at certain rpms. Yes ASP has taken this into consideration and designed it in a way to mitigate this issue. They make crankshaft and supercharger pullies for various cars, many with way more power than the coupe and that's what they do best. I would assume that Kleemann with his vast experience with MB motors factored this into his pulley.

mdp c230k

Not all harmonic balancers use moving counterweights, most don't actually, they use a weighted ring that is suspended by rubber like the stock unit does. The idea is that this suspended mass is tuned to vibrate at given resonances specific to each engine to dampen the flexure of the crankshaft. If there is no suspended mass, as on a solid pulley it would have to be rotationally balanced with the rest of the reciprocating parts of the engine (as in the phrase 'balanced and blueprinted', blueprinted is where every part matches the weight of the others of its type i.e. piston=piston, rod=rod). The need for perfect balance is less on a motor with heavy duty main bearings to control the crank flexure. The power an engine creates is not a factor here. The desired max rpm and the weight of piston/rods and the stroke are all factors.

Buellwinkle

Have you seen, touched, smelled the factory pulley off the car? For all I know, this rubber like strip is only about 1/2" deep at most. The factory pulley is one solid piece of metal with a groove cut into it for this rubber. It is not a harmonic balancer in any sense of the word. There is nothing floating. This is not like the V6 MB dampers what are 2 seperate pieces of metal joined by the rubber damper. The only non-mechanical balancers I've seen have a hollow tube filled with Mercury to balance the vibrations.

For those that come to the BBQ this weekend in San Diego, I'll bring the factory pulley/damper. See that bugger for youself.