Boostless97Lude

yeah, this question has been asked a few times, but no one has ever really answered it all that well

hybridsol

I'm running one now. Haven't seen any bad things... yet. But hey, who knows?

My lights dim when the car idles though....

Sean

Boostless97Lude

do you have a complete pulley set or just the crank pulley??? how many miles on the engine since turbo and pulley???

Canuk_SiR

I've had the pulley on for a while though, a UR crank pulley (ultra R) on a bone stock engine for about 25-30k. no problems with it at all.
It'll see boost this spring

supercompact

Has something to do with the lack of a harmonic balancer. I have heard that the harmonics from a nonharmonically balanced crankshaft pulley will cause the main bearings to wear more quickly. Of course that could be complete BS. Just what I have heard.

Boostless97Lude

um, harmonicly balanced mean what exactly??? stupid question i am sure

hybridsol

Well, all I needed was the alum underdrive pulley- no a/c or p/s (I'm hardcore YO!)

I've put about 500 mi on it so far... no crazy noises yet. I've heard the D-series engines are not balances as good as the B-series, and can couse problems with the #1 main bearing. Called the Mfgr (can't remember- A??) anyway the guy said he never had anyone complain about spinning a bearing, except on a Rotary, and he had other probems... I read a post on DarkSol (Del Sol board) and they ran one for a while on a 13:1 n/a car. When they finally tore it apart after 2 years of 1/4 sprints, they posted pics, no evidence of wear....

supercompact

You know how something that spins sometimes makes a humming noise (washing machines are a good example), that is harmonics. The stock crankshaft pulley has a rubber section between the inside and outside of the pulley that dampens the harmonics of the spinning assembly. Harmonics are pretty much just high pitched noise.

Civic_intent

You're right on the pulley.
Very close, but not exactly. Harmonics are the vibrations caused by the rotational forces and combustion process. Not really high-pitched sounds, they actually range all over the audio spectrum.

Boostless97Lude

ok, that's what i thought actually, i just couldn't come up with the words , could i have one balanced harmonically??

niedejb

Nope. It absorbs the harmonics of the cylinders firing.

These harmonics would be difficult (if not impossible) to simulate on a balancing machine.

servion

Do any aftermarket crank pulleys have a sort of harmonic balancer?

I've got a friend who swears they are great (the lightweight crank pulleys), but I'm afraid to use one... simply because I don't know of any of them that act as a harmonic balancer.

What about the other end of the crank... can lightening a flywheel cause the same sort of concern?

twkdCD595

Honda's need a harmonic damper on the crank pulley... least thats been the general consensus... f/i or not.

The harmonic damper on the pulley is said to prevent fatigue and failure... least thats what I thought.


[Modified by twkdCD595, 10:12 PM 1/23/2003]

paulzy

iTrader: (1)

I remember JG was designing something with edelbrock for hondas...crank pulley with a harmonic balancer

twkdCD595

wish I could remember the site for pics and all but here was a piece written about a similar problem although different car manufacturer and what not... (long, but very intresting).

The Danger of Power Pulleys &
Understanding the Harmonic Damper
By Steve Dinan


I have been threatening for a long time to write a series of technical articles to educate consumers and to dispel misconceptions that exist about automotive after-market technology. Motivated by problems with customer's cars resulting from the installation of power pulleys, I wish to explain the potential dangers of these products and address the damage they cause to engines.
The theory behind the power pulley is that a reduction in the speed of the accessory drive will minimize the parasitic losses that rob power from the engine. Parasitic power losses are a result of the energy that the engine uses to turn accessory components such as the alternator and water pump, instead of producing power for acceleration. In an attempt to minimize this energy loss, many companies claim to produce additional power by removing the harmonic damper and replacing it with a lightweight assembly. While a small power gain can be realized, there are a significant number of potential problems associated with this modification, some that are small and one which is particularly large and damaging!
The popular method for making power pulleys on E36 engines is by removing the harmonic damper and replacing it with a lightweight alloy assembly. This is a very dangerous product because this damper is essential to the longevity of an engine. The substitution of this part often results in severe engine damage.
It is also important to understand that while the engine in a BMW is designed by a team of qualified engineers, these power pulleys are created and installed by people who do not understand some very important principles of physics. I would first like to give a brief explanation of these principles which are critical to the proper operation of an engine.
1) Elastic Deformation
Though it is common belief that large steel parts such as crankshafts are rigid and inflexible, this is not true. When a force acts on a crank it bends, flexes and twists just as a rubber band would. While this movement is often very small, it can have a significant impact on how an engine functions.
2) Natural Frequency
All objects have a natural frequency that they resonate (vibrate) at when struck with a hammer. An everyday example of this is a tuning fork. The sound that a particular fork makes is directly related to the frequency that it is vibrating at. This is its "natural frequency," that is dictated by the size, shape and material of the instrument. Just like a tuning fork, a crankshaft has a natural frequency that it vibrates at when struck. An important aspect of this principle is that when an object is exposed to a heavily amplified order of its own natural frequency, it will begin to resonate with increasing vigor until it vibrates itself to pieces (fatigue failure).
3) Fatigue Failure
Fatigue failure is when a material, metal in this case, breaks from repeated twisting or bending. A paper clip makes a great example. Take a paper clip and flex it back and forth 90° or so. After about 10 oscillations the paper clip will break of fatigue failure.
The explanation of the destructive nature of power pulleys begins with the two basic balance and vibration modes in an internal combustion engine. It is of great importance that these modes are understood as being separate and distinct.
1) The vibration of the engine and its rigid components caused by the imbalance of the rotating and reciprocating parts. This is why we have counterweights on the crankshaft to offset the mass of the piston and rod as well as the reason for balancing the components in the engine.
2) The vibration of the engine components due to their individual elastic deformations. These d

BudaKai

Yeah, btu look at who's doing it again? Think they'll do us good this time around? I don't....

That is one helluva post that I could have said in like 10-15 words.

twkdCD595

sorry but how you say that in 10-15 words... if you meant my post.

I thought it was intresting myself.


[Modified by twkdCD595, 12:04 AM 1/24/2003]

93civEJ1

My car must be out of tune, because there is nothing harmonic about mine!!!!

Boostless97Lude

twkdCD595: i am not sure i fully understand. i don't see how it could affect the water pump or fan on a Honda..... i see how it can affect voltage and what not at idle, but i have a question. if my complete rotating assembly as been balanced and blueprinted, then could an underdrive pulley really affect harmonics all that much? especially since the H22 is equiped with balance shafts. no, i am not questioning you, that was jsut not clarified, and if you could be more specific, please do be

Boostless97Lude

ttt

p0gi

I bought a used japanese d16z6, and it came with a stock honda crank pulley that didnt have a damper on it. So you cant really say that they all need it.

EK9LSTURBO

im running a UR ultra R crank pulley on my fully built turbo motor, and have noticed a couple of problems.. first off my my volts are messed up, if my alarm goes off, than the battery completely dies.. although i have no problems when the car is on, the lights dont dim etc.. so im not sure if my alternator is charging right, have get that checked.. but this is wat Unorthodox had to say about ur question...and ive also noticed that u can actually hear alot of funny noises from the motor alot alouder, dunt know if thats from the internals of my motor, but u can here the crank spinning and stuff and the belts spinning.

heres a pic of my motor with the pulley


from the QA on the there website..

3) "Isn't my stock crank/eccentric pulley a balancer, harmonic/torsional, or vibrational damper?"
A common misconception is that factory crank pulleys on certain vehicles are harmonic dampers. The fact is, on todays late model cars the factory crank pulley is designed to reduce NVH (noise / vibration / harshness), which does not affect crankshaft or bearing life. These are noises and vibrations from the engine compartment that may travel into the cabin of the vehicle when the engine is running and the stock crank pulley is used to reduce NVH for the occupants (similar to the use of resonators in the intake to quiet intake noise). We do not manufacture crank pulleys that replace or eliminate a damper in applications where the factory crank pulley is an actual harmonic damper (such as 90 degree V engines).

Our pulleys are lightweight, CNC-machined 6061-T6 aluminum and are by design "0" balanced. Because of this, owners have called to tell us how much smoother their engine feels after installing our pulleys. Unorthodox Racing has been manufacturing and selling pulleys for over 5 years without a single engine failure due to the replacement of the stock crank pulley. This is testament to the quality and reliability of our products.

Owners who have engines that use balance shafts must understand that if they eliminate their balance shafts their engines must be balanced and blueprinted if they expect to have no long-term engine problems with or without the use of our crank pulleys. This balance shaft elimination is rare and only happens on a few models that are modified for racing only (Eclipse/Talon/Laser/Galant VR4/Conquest TSI/Starion just to name a few).

4) "Will the underdrive pulleys cause my engine to have premature bearing wear ?"


This is a fear many prospective owners have and it is a valid concern since we are dealing directly with the rotating assembly. It is, however, a fear with no basis in fact. The fact is that our pulleys have the opposite effect on engine bearings. The combination of tight tolerances, quality control, perfect balance, and dramatic weight loss versus the stock pulleys reduces the stress on your engine extends the total service life you can expect from your engine. Engine bearing problems are purely associated to poor engine maintenance, use of heavier than factory recommended oils, improper engine building practices which includes poor balancing, excessively revving engines when they are cold, and owners expecting their factory oil pumps to handle engine HP outputs 2-3 times over stock HP levels.

Boostless97Lude

so, basically, this is just another one of those myths, like "NOS is dangerous"

EK9LSTURBO

hahhaha man theres always some type of logic to things people say.. becuase in the wrong hand nos can be very dangerous, and detrementale to ur car.. just do it right the first time and do ur hw. and dunt be cheap about things.. if ur gonna do it.. do it right or dunt do it at all..

zeta_msz_006

Please take anything you read on UR's website with a grain of salt, after all they are the ones who manufactures the crank pulley. That's sort of like asking a used cars sales man if there are problems with the car you are about to buy from him!!

I find that kind of funny that UR claims that "We do not manufacture crank pulleys that replace or eliminate a damper in applications where the factory crank pulley is an actual harmonic damper." Yet the link below shows a documention from Toyota which saids otherwise. Either the UR sites information is not entirly accurate, or UR knows more about Toyota engines than Toyota themselves!!!

http://www.supras.com/~riemer/sonict...atedamper.html




[Modified by zeta_msz_006, 1:21 PM 2/5/2003]