some very good information going on at c32life.com

http://members5.board*********/MBC32/msg/32535.html

http://www.dinanbmw.com/html/danger_...er_pulleys.htm

obviously, it is important to note that there are 2 schools of thought here. kleemann has had his pulley (no damper) for quite a while now, and of course, they've tested it in other cars w/out a problem. the renntech has the damper, but vadim@evosport points out that the way the pulley is designed, renntech has effectively created a no-damper pulley (not sure why or how? i asked renntech about this but i find it hard to believe that they would obviate the effects of the damper like that). also, note that the c32 guys are talking about a V-6 engine vs the I-4 of the coupes... again, not sure about the ramifications. however, kleemann says that the I-4 is inherently more unbalanced(?) than a V-6 (which to me, implies that the damper is more critical...)

anyway, i'd like to hear from people w/ more expertise on this.

or is this a subject with inherently different schools of thought and the subject is moot?

also, i do not intend to disparage any pulley. i think any pulley upgrade has risks and you should be making the most informed decision. i say that if you are in any way concerned, do not get a pulley upgrade and save up for an amg

 

Adding a heavy weight ring to the factory pulley is going to alter it's harmonic characteristics. Can any of the pulley ring tuners show us a chart of crankshaft twisting across the rev range before and after adding a ring? If none can show this then it's all B.S., they don't have "real engineers" and haven't done all the math and testing.

I slight understanding of why the damper is there would help since most are good at buzz words but have no idea what they are saying, heck I'm probably one of them. When a cylinder fires it puts pressure on the crankshaft and it causes it to twist slightly. It is considered normal if the crankshaft twists up to a 1/2 degree. Depending on the rev range, usually at the higher RPMS the crankshaft may twist more and there is usually a peak for a short duration at where this may exceed a 1/2 degree. On cars with long driveshafts and a long stroke like an inline 6 on BMWs, the twisting is more pronounced and a damper is more critical. On a small sturdy engine like the MB 2.3l, the crankshaft is relatively short and the torsional vibrations are not severe enough to cause a crankshaft failure or Kleemann alloy pulleys that have been made for a while on C230K sedans and older SLK230s would be experienceing crankshaft failures. Now if this was happening, why would Kleemann introduce a whole new alloy pulley for the Coupe? So why did MB put a harmonic damper on the pulley? Most likely to reduce vibration for comfort reasons and probably to a lesser degree, increased engine life.

I've owned what many considered to be the most unbalanced engine in the world, a Harley. The engine vibrates so bad that many companies like Honda strive to make their engines vibrate as much so it feels like a Harley. Harley's vibrate mainly because of their single pin crankshaft and no vibration damper. Yet these engines last a long time. The crankshaft doesn't self destruct, at least none that I've heard about. What blows up Harley motors? Arrogant tuners that sell intakes, exhausts, cams and such without taking into consideration air fuel ratios causing cracked cylinders and pistons and that I have seen. Now I added a Fisher Damper to the crank on my hog and that reduced vibrations considerably but like MB, I did it for comfort and not engine life.

The issue will keep coming up over and over again as some like to stir up the mud. So if you feel the factory damper is still valid even after adding a ring, then for $599 you can't beat the Kleemann ring. If you want the extra ponies that an alloy pulley like ASP or Kleemann can give and you believe like I do that nothing really bad will happen then go that way. Whichever way you go, make sure you addressed the air fuel ratio issue, either through a fuel regulator, fuel pump calibration or ECU programming because that will without doubt cause you big time grief. And lastly, whatever you do, do not but a solid pulley on a BMW or Supra.

 

Buellwinkle,
You are very wrong on so many counts it would be futal to try and explain where. I suggest that you stop mis-informing the people on this board until you get a true understanding of what you are talking about. As just a starting point, it has little to do with crank failure, its about the bearings. I had mentioned harmonic balance a long time ago in a post and told some of its importance. Talk to the builder of good hi-perf engines about the importance of proper balance throughout the system. Yes, the ring does something your solid pulley can't, it maintains the original balance, not resonance, of the engine. You will find that your HD example is plain old nonsequatorial as a two cylinder two stroke(even 4 stroke) has zilch in common with a inline 4 as far as balance goes. For true balance your statement of the inline 6 being too long is a load of crap. The inline 6 is the most inherently balanced engine short of a rotary. In short stick to something you know about, it ain't cars.

 

Sorry but you have an understanding of it from muscle car days and yes an old Chevy 350 that's been worked up would require a damper and in some cases a fluid or mechanical damper and not the cheezy rubber one the factory gives you. But take today's really high performance inline 4 like that on the very high reving Honda S2000. Honda realized that to make fast, high reving engines they had to eliminate the damper and use lightweight solid alloy pullies. But lets assume that you are correct and the factory pulley with the harmonic balancer ring on the back was necessary. Wouldn't adding a few pound ring to the pulley and crankshaft shift the natural frequency of the vibrations and render the modified pulley not only useless but possible cause resonation at other frequencies? Also wouldn't the rubber compound harden over time making it less effective?

As for your remark on causing bearing failures, has anyone in the 5 or so years that the 2.3L motor has been out with aftermarket pulleys complained about bearing failures or is this some wild **** theory of yours and not reality? Who's missinforming who? Do you have proof for this motor?

By replacing the easy to manufacture cast iron pulley with a CNC machined balanced lightweight solid alloy pulley you are putting less strain on the bearings from both lighter weight and better balancing. Adding a heavy ring to the outside perimeter of a factory pulley would seem like it would put more stress on the crankshaft bearings and cause more torsional vibrations.

 

You are wrong again! My knowledge is of current high perf engines, when did I say anything about big blocks or american metal? The Honda S2000 uses very light components and has a very well balanced crank to acheive their goal. The resonance of the damper is not changed by the addition of pulley ring as the mass of the rubber isolated sub unit is not changed. It is the subunit that damps the vibration. The ring is balanced by the nature of a circle and will not change the relative balance of the crankshaft. Yes, rubber does harden over time, but it will be no worse than your head after as many years. Next, I said nothing about someones bearings failing, I said this is where the concern would lie, not in a crankshaft braking as you implied. Someone recently mentioned that when he took his engine apart the bearings got worse as you went from back to front on the engine. I find you gleeful ingnorance amusing. You should really read some books or take a class before making ignorant statements as if they are fact. I grow tired of you foolishness now. Til the next time I see you writing about what you do not know...

 

We has discussed this issues so many time !!!! If the "harmonic Balancer" does not do anything then WHY ON EARTH MERCEDES INSTALLED ON THE ENGINE !!! Why do we need to put weight on the wheel when we balance the tire? Why do Mercedes used "shock absorb" on the pulley tensioner? Why do Mercedes used fluid fill engine mount and not solid engine mount? Everything was design is for a reason.

 

ok, i now understand that the harmonic damper is not obviated by adding a ring to the oem pulley.

kleemann says, "For once and for all- for a crank pulley to have a "damper" it has to be a mass isolated (suspened or whatever you want to say) from the pulley- period! Adding mass near the front main bearing (while being a contiguous whole with the pulley) DOES NOTHING!"

 

Young, thats right.. The ring maintains the damper. It also does nothing to the balance as the ring goes around the crankshafts axis of rotation.