Harmonic balancer discussion from "Info on powder pulleys" thread

[Tygen1]

Also, what are the effects of eliminating the harmonic balencer? Won't overdriving the alternator just cut into that 5hp gain?

[TheGhostInTheMachine]

ZX2's don't have a harmonic balancer.

[Tygen1]

I believe I remember there being a rubber area between the pulley and the inner part of the crank pulley, seems like that'd be a harmonic balencer? Is this correct?

[powder]

More like a dampener than a harmonic balancer. The zetec is internally balanced and there is no need for a harmonic balancer.

[Tygen1]

More like a dampener than a harmonic balancer. The zetec is internally balanced and there is no need for a harmonic balancer.

Internally balenced only means the rotating assembly does not need an external weight balence the rotating assembly. The harmonic balencer (dampner) counteracts the rotational acceleration and deceleration of the crank.

From Wikipedia:
"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.

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.

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.

There has been a trend at times by some "performance enthusiasts" to remove the harmonic balancers on their cars, usually when the balancer is attached to the crank pulley. The argument is that they aren't necessary and their mass reduces the performance of the engine. Others[who?] argue that this is not worth it, 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.

While net engine output can be increased without harmonic balancers, in professional race cars harmonic balancers are still commonly equipped, for reasons ranging from safety concerns to regulations. Almost all modern car manufacturers, even "performance" car makers and specialty tuners, include a harmonic balancer on their vehicles, and removal voids vehicle warranty."

It's been awhile since I was in school learning this stuff, but I recall having a discusion with my teacher about this subject of removing the harmonic balencer. He was a mechinic from the '60's and had seen a few cranks break, but in those days the Harmonic balencer was also used to balence the motor, ie: externally balenced. You were also dealing with 300hp V8's, so a 5 hp increase was so minimal that it didn't justify the possible breakage. It may not be such a big deal with our modern, stronger materials, and better balence, and interanaly balenced motors. I suppose the proof is in the pudding and if no one elses has broken a crank, then I will probably be the first ;)

[TheGhostInTheMachine]

We can all quote wikipedia too. We have yet to hear of a single Zetec that has failed because of a UDP. I had powder's UDP on my boosted ZX2, no problem.

[powder]

Internally balenced only means the rotating assembly does not need an external weight balence the rotating assembly. The harmonic balencer (dampner) counteracts the rotational acceleration and deceleration of the crank.

From Wikipedia:
"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.

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.

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.

There has been a trend at times by some "performance enthusiasts" to remove the harmonic balancers on their cars, usually when the balancer is attached to the crank pulley. The argument is that they aren't necessary and their mass reduces the performance of the engine. Others[who?] argue that this is not worth it, 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.

While net engine output can be increased without harmonic balancers, in professional race cars harmonic balancers are still commonly equipped, for reasons ranging from safety concerns to regulations. Almost all modern car manufacturers, even "performance" car makers and specialty tuners, include a harmonic balancer on their vehicles, and removal voids vehicle warranty."

It's been awhile since I was in school learning this stuff, but I recall having a discusion with my teacher about this subject of removing the harmonic balencer. He was a mechinic from the '60's and had seen a few cranks break, but in those days the Harmonic balencer was also used to balence the motor, ie: externally balenced. You were also dealing with 300hp V8's, so a 5 hp increase was so minimal that it didn't justify the possible breakage. It may not be such a big deal with our modern, stronger materials, and better balence, and interanaly balenced motors. I suppose the proof is in the pudding and if no one elses has broken a crank, then I will probably be the first ;)

That little rubber thing is not a harmonic balancer.

Aluminum naturally absorbs vibration.

[Tygen1]

That little rubber thing is not a harmonic balancer.

Aluminum naturally absorbs vibration.

The whole assembly is the harmonic balencer :) The rubber allows the outer ring to dampen the natural acceleration and deceleration forces twisting the crank. I got no need to quote wikipedia, I just thought it was a good explanation and ctrl-C, ctrl-V is way easier than typing it all out. I don't really understand why you guys don't think this is a harmonic balencer, it looks like every other one I've seen before. Oh well, it's a silly thing to argue anyhow, you can believe what you like, I'd put the UDP on anyway. Like I said the proof is in the pudding. Theory don't count for jack if real life doesn't prove it to be true.
Second point, even if Aluminum was able to "absorb vibrations", it is not vibration that the dampener is absorbing, rotational accelerations and decelerations, like a shock absorber for the crank. Axial not radial motion...you may have to look that one up on Wiki ;) I knew those engineering classes would pay off someday...

[powder]

There is no "if". Aluminum absorbs vibration.

You obviously haven't seen many harmonic balancers. None that i have seen are built into the pulley, they are attached and individually balanced to that pulley.

Please tell me how it is absorbing axial motion. That is not soft rubber, and it does not move to absorb any kind of shock. From what you're saying it is absorbing backlash from reving up and down. If it cannot move, this is not true.

It's a dampening barrier. The sooner you realize and accept this, the better off everyone will be.

[Tygen1]

This is a worth while discussion. Check this out...
http://www.epi-eng.com/propeller_reduction_technology/torsional_vibration_issues.htm
http://www.economicexpert.com/a/Harmonic:balancer.html
http://www.partstrain.com/ShopByDepartment/Harmonic_Balancer
http://www.carpartswholesale.com/cpw/harmonic_balancer.html
Seem like I'm not the only who thinks this is a harmonic balencer...

[powder]

There is no "if". Aluminum absorbs vibration.

You obviously haven't seen many harmonic balancers. None that i have seen are built into the pulley, they are attached and individually balanced to that pulley.

Please tell me how it is absorbing axial motion. That is not soft rubber, and it does not move to absorb any kind of shock. From what you're saying it is absorbing backlash from reving up and down. If it cannot move, this is not true.

It's a dampening barrier. The sooner you realize and accept this, the better off everyone will be.

You forgot to address that.

Also, if that is a harmonic balancer, why is the pulley balanced? Also, why when put on an indicator does the ID to OD run out exceed .02 on some stock crank pulleys. It would seem to me that this dampening barrier creates the very vibration you're saying it's made to absorb.

You can trust that i have done my research on this, as i designed my pulley myself, off of a half dozen stock crank pulleys and the average dimensions between all of them.

You seem to just be quoting other people's research and experience, and not your own. I would highly advise against this.

Lastly, i cannot click your links because i'm not going to jeopardize my job. If it's not about the ZX2 though, any point made is moot.

[TheGhostInTheMachine]

This is a worth while discussion. Check this out...
http://www.epi-eng.com/propeller_reduction_technology/torsional_vibration_issues.htm
http://www.economicexpert.com/a/Harmonic:balancer.html
http://www.partstrain.com/ShopByDepartment/Harmonic_Balancer
http://www.carpartswholesale.com/cpw/harmonic_balancer.html
Seem like I'm not the only who thinks this is a harmonic balencer...

None of those parts sites list anything that even remotely resembles the OEM ZX2 crank pulley. lol



Please tell me how it is absorbing axial motion. That is not soft rubber, and it does not move to absorb any kind of shock. From what you're saying it is absorbing backlash from reving up and down. If it cannot move, this is not true.

It's a dampening barrier. The sooner you realize and accept this, the better off everyone will be.

What he said ^

[Tygen1]

Maybe this will help explain how axial acceleration and deceleration act on a crankshaft. I've also included a screen shot from Alldata listing the crankshaft pulley as a harmonic balencer, it has the part number if you wish to double check.
It is not possible for me to not quote others work because I have not the means to prove or disprove either of our ideas about the "crankshaft pulley". It seems some very educated folks believe that the device attached to the nose of the crankshaft, with a rubber sleeve and steel ring on the rubber sleeve is called a harmonic balencer. I have done my research many years ago to figure out what a harmonic balencer is, why it is there and how does it work, well before such great info was availble on the net. I hope the attached article explains what a harmonic balancer is and it's purpose so we can all better understand.
Yea, Vit, it is inevitably that the guys trying to sell the parts are trying to prove they are right. Thus the links to parts sites. Not ripping on you Powder, it's just that most of the info that is easily accesable on the net is from guys trying to sell stuff. Maybe you guys remmber the mid to late eighties model GM turbo diesels breaking the nose off thier cranks regularly. Seems the harmonic balencer was not large enough to dampen that big torque. I was hoping the links I provided would encourage you guys to do some more research to bring evidence that what you are saying is correct. Let's not get into an arguement of opinion. This issue is a mater of science and physics and can be proven or disproven without opinion. I should have no need to give an opinon on how soft the rubber is, or how aluminum is not abosrbing any significan amount of vibration, or how any rotating assembly must be balence to some degree when the info is easily available. I trust we have all read up and have a good understanding of how stuff works, please bring me some hard evidence that will make me re-consider this crankshaft pulley not being a dampner other than opinions about how stuff works.
Although this might stir up a little anger, take it with a grain of salt and do some reading. I will have no shame or hesitation to admit I was wrong if you are able to prove your point with evidence.

[Tygen1]

Here's some info on the ability of Aluminum to absorb vibration, no quotation here, came up with this myself in order that you might believe I am not some 15 year old pimpled punk sitting in home room linking to useless info from the net.
In order to absorb any type of vibration, or rotational torque vibrations, the crankshaft pulley center must accelerate at a force great enough that the load (this load can be expressed as the resistance to movement by the inertia of the pulley plus the accessories) at the outside of the crankshaft pulley will be sufficient to cause the metal to deflect, either axially or radialy. Similar to a rubber band expanding then springing back. The normal measure of this type of "elastic" movement is called the Youngs Modulus. This measure can be expressed in lbft/inch squared. The Modulus of Aluminum is 10,000,000 lbft/inch squared, the Modulus of Rubber is between 1,500 and 15,000 lbft/inch squared. If you are able to do the math, you will see that the tiny aluminum pulley will not be able to absorb any significant amount of energy, vibration or torque vibration. I can do the math for you if you would like to see just how much energy it would take for ten million lbft/inch squared of resistance to "absorb" it. It is evident just from the Modulus of Rubber that the engineers who have been designing cars for years believe that the rubber ring of a harmonic dampener is able to deflect at the forces generated by the motor.
Are you still not convinced this crankshaft pulley is not a harmonic balencer?

[TheGhostInTheMachine]

You can call that crank pulley whatever you want if it makes you happy. However it is not 2 pieces, hence it cannot move and function as you believe it can.

[powder]

Here's some info on the ability of Aluminum to absorb vibration, no quotation here, came up with this myself in order that you might believe I am not some 15 year old pimpled punk sitting in home room linking to useless info from the net.
In order to absorb any type of vibration, or rotational torque vibrations, the crankshaft pulley center must accelerate at a force great enough that the load (this load can be expressed as the resistance to movement by the inertia of the pulley plus the accessories) at the outside of the crankshaft pulley will be sufficient to cause the metal to deflect, either axially or radialy. Similar to a rubber band expanding then springing back. The normal measure of this type of "elastic" movement is called the Youngs Modulus. This measure can be expressed in lbft/inch squared. The Modulus of Aluminum is 10,000,000 lbft/inch squared, the Modulus of Rubber is between 1,500 and 15,000 lbft/inch squared. If you are able to do the math, you will see that the tiny aluminum pulley will not be able to absorb any significant amount of energy, vibration or torque vibration. I can do the math for you if you would like to see just how much energy it would take for ten million lbft/inch squared of resistance to "absorb" it. It is evident just from the Modulus of Rubber that the engineers who have been designing cars for years believe that the rubber ring of a harmonic dampener is able to deflect at the forces generated by the motor.
Are you still not convinced this crankshaft pulley is not a harmonic balencer?

No i'm not actually.

And you're quoting aluminum as a whole, i'm saying in a zx2's rotating assembly, aluminum will absorb the little amount of vibration that one of my pulleys may transmit, much better than steel will.

It's about time to stop cluttering my info thread, so i'm going to move this whole conversation to it's own thread.

[Tygen1]

You can call that crank pulley whatever you want if it makes you happy. However it is not 2 pieces, hence it cannot move and function as you believe it can.

I'm not the only one calling it a harmonic balencer, Ford does also. Yep, I checked, the pulley is not 2 pc's it's 3. An inner hub, a rubber ring and an outer steel ring. Pic attached.

[QUOTE=And you're quoting aluminum as a whole, i'm saying in a zx2's rotating assembly, aluminum will absorb the little amount of vibration that one of my pulleys may transmit, much better than steel will.[QUOTE]

This doesn't really make sence. Yes Aluminum is able to absorb vibration better than Steel, but both are way off the charts in how much energy is required to make the metal elasticly move. Thus the rubber ring on a harmonic balencer. Have you read the article I posted up? Please read it, it is a very very good explaination.

Mech, what do you say? Can you settle this for good?

[scort2498]

mech knows alot of stuff but is not all god at zetecs or harmonic dampeners... i would ask john p if anyone.

[carguy07]

if you think his pulley will mess up your car don't buy one.

i think it's that simple.

[ImCrazy]

if you think his pulley will mess up your car don't buy one.

i think it's that simple.

yeah why a n00b would come in and question vit, and powder is beyond me... upds won't hurt the zx2's motor end of story.

[capitalcrew]

Hey fool. Stop posting. As soon as one of us has a problem with powders pulley we'll be sure to post about it. Since he has been making them for a few years now, with no problems, I doubt we will have any though.

Cutting into the gain? The gain was figured out on a dyno, not from a guess.

[capitalcrew]

Oh and by the way, fool, if powder is doing it wrong then why does esslinger and ford racing do it the SAME WAY.

[Kilroy]

Guys... WTF? It's not like this dude is coming in here acting like an idiot, he is presenting himself in a very clear and mature manner. No need to jump down his back, he's just sparking discussion and I for one think it's cool that someone is trying to figure out the exact physics instead of us all just taking someones word for it. I've used UDPs with no problem in the past and will continue to do so, but at least he's taking the time to type out well thought out responses and not just two liners that you guys are throwing at him.

Game on.

[Tygen1]

Yep I'm a noob here....so that makes me not know what I'm doing huh, right? I'm not gonna brag about what I've done, you guys will just have to figure that out. :)
Again, not questioning Powders product. Just curious about if there have been any problems with removing the harmonic balencer, apparently not, like I said the proof is in the pudding. The question at hand now is if the pulley on the nose of the crank is a harmoinic balencer or not.
The question still in the back of my mind is the mpg and hp gain worth the possible problems in the future. I doubt most of you guys intend to put the number of miles on this car as I do. I am currently at 226K and will continue to pile up the miles until the car is completely done for. I wonder what the effect on the crank and bearings would be after another 100K? I'm definatly wanting to try and find out for myself.

John P., you out there???
Anyone care to contribute something other than pointing out my ubber noobness :)

[TheGhostInTheMachine]

My first engine had crankwalk well before I started modding it. Ditching the stock pulley actually helped my car idle and run smoother. Then I boosted my second engine... again using powder's UDP. You know... only 3x more torque than a stock engine makes... and no problem. Whether or not the stock crank pulley is a harmonic balancer, it's worthless and just a huge weight on the ZX2. Heck I don't even remember what it looks like since I haven't seen a ZX2 for over 2 years, lawl.

[ZX2Fast]

I've been under a lot of ZX2's and not once have I seen a crank pulley that looks like that one. Unless you bought this car new, I would guess this was put on it after market. Perhaps the stock pulley failed and they used a replacement that happens to be a 3-piece.

[TheGhostInTheMachine]

I've been under a lot of ZX2's and not once have I seen a crank pulley that looks like that one. Unless you bought this car new, I would guess this was put on it after market. Perhaps the stock pulley failed and they used a replacement that happens to be a 3-piece.

Thank you. None of mine looked like that one either. They were all solid one piece units.

[wifeszx2]

When I pulled the stock pulley off my ZX2 and installed the UDP I remember the stock pulley being 1 piece, or atleast the pulley came off in 1 piece. It very well could have been 2 or 3 pieces assembled as 1 and just came off that way. I never had any problems with the UDP. It was not only smaller but lighter too. The only problem I heard with Powder's was lights dimming at idle because it was so small it turned the alt too slow, but this could be cured with an Alt ODP and/or SCT.

[gunman_sr5]

The rubber ring is an elastomeric bearing. On the Thunderbird SC they are notorious for failing. With that motor it is the balancer and the motors don't last but a few seconds after it fails. There are aftermarket one piece billet units that are recommended replacement for the SC. With the Zetec being internally balanced there is no need for a larger balancer (counter weight).

[Tygen1]

The picture is the original motor, my wife bought the car new in '98. Last fall I put another motor in it, bought from Yellow2000SR. It was also a '98 motor and has the exact same pulley. I replaced the original motor because of excessive crank walk after 215K. Odds are that the dangerous harmonics for the Zetec are at an rpm range that the motor hardly ever opperates at. My understanding is that the dampener is critical on some motors that have intencse harmonics at engine speeds it normally turns at, ie: mid eighties turbo diesel GM's, T-bird SC's etc... If this is the case, then this is why we don't see the nose of the cranks snaping like twigs when UDP is installed.
A harmonic balencer is not a counter wieght or any sort of device used to balence a motor (although some are used in that fashion also if the motor is externally balenced). Please read the atached article. It more than explains why harmonic balencers exist.

[capitalcrew]

I go through quite a healthy range of RPMs daily, and have no problems.

Explain to me why if this is a critical part esslinger and ford racing both leave it out.

[ZX2Fast]

I've removed the engine from my wife's 98 (manufactured in 3/97) and it had a one piece. The pulley in my 98 (manufactured 8/97) was a one piece. My car sees 7200 rpm upshifts daily with a Ford Racing UDP. It has over 170,000 miles on it and has been boosted for two years. No signs of failure or any hints of bearing noise. Maybe you got a left over Contour engine in your car.

[iceracer]

For what it is worth, Ford calls it a pulley. I too drive at varying rpms. Do consideable high rpm 4k to 7+k rpms for hours. I have the Esslinger udp and absolutely no problems.
After looking at my stock pulley. It does have a pastic/rubber ring between the inner and outer pieces. It is also balanced. Since it is a drive Pulley I am thinking it has more to do with driving the accessories. It is not a harmonic balancer since a balancer does nothing else, the accesory pulley is a seperate piece.
I have seen thousands of four cylinder engines that had no form of a balancer and no broken cranks.

[iceracer]

It is not a harmonic balancer. Even Ford calls it a pulley. My 2000 stock pulley has a plastic/rubber ring betwen the inner and outer pieces. I an thinking this may have something to do with driving the accessories. How can it do any harmonic balancing while it is driving the accessories ?
A harmonic balancer serves no other purpose, the accesory drive is a seperate pulley.
I have seen thousands of 4cyl. engines that had no sort of balancer and no broken cranks.
I also run my engine at hight rpms a lot and no problems with my Esslinger UDP.

[iceracer]

Sorry for the double post. Just had some more thoughts on the subject.

[Kilroy]

Sorry for the double post. Just had some more thoughts on the subject.

So you triple posted to apologize for a double post? ROFL! :partynanas:

[Tygen1]

It is great to hear so many guys that have high miles with the UDP and no problems, gives me confidence in the pudding.
I will still stand by the pulley being a harmonic balencer because this part meets every description of harmonic balencer that I have ever read. Check my previous post for the Alldata screen shot calling it a harmonic balencer. The term balencer is a misnomer though, it is really a dampener. A shock absorber, if you will, to deal with crank twist under the severe impact of the rod banging down on the journal during the power stroke.

[Tygen1]

Someone needs to write up a how to on double posting so I can get my post count up :)

[ravensguildassasin]

ok the crank pulley being a harmonic balancer is about as true as the zx2 engine being a interference motor. just because you found one site that says it is does not make it true. im sorry that the reference material that you have read makes you think it is something it is not. i read it to and i still do not think it is a harmonic balancer. now here is the difference you have to look at, when the crank pulley is twisting there is no way for it to do anything else. imagine that the pulley is two pieces, under load it is already twisted to its maximum elasticity, because there is a belt forcing it stay under load. now on a harmonic balancer it is free standing no belt attached there so there is no outside force to hinder it from doing what it should. but the ultimate truth is that you will still say the same couple of lines calming that it is a harmonic balancer.

[xtremecaraudio]

ok the crank pulley being a harmonic balancer is about as true as the zx2 engine being a interference motor. just because you found one site that says it is does not make it true.

ding ding ding, I think we have a winner.

Almost every place you go (including AllData) will tell you the zx2 has an interference engine when we don't. They are not always right.

[Tygen1]

ok the crank pulley being a harmonic balancer is about as true as the zx2 engine being a interference motor. just because you found one site that says it is does not make it true. im sorry that the reference material that you have read makes you think it is something it is not. i read it to and i still do not think it is a harmonic balancer. now here is the difference you have to look at, when the crank pulley is twisting there is no way for it to do anything else. imagine that the pulley is two pieces, under load it is already twisted to its maximum elasticity, because there is a belt forcing it stay under load. now on a harmonic balancer it is free standing no belt attached there so there is no outside force to hinder it from doing what it should. but the ultimate truth is that you will still say the same couple of lines calming that it is a harmonic balancer.

You make good point. It is very reasonable to see that what you are saying can be true. This is the only "harmonic balencer" I have seen that is driving an accesory belt off the outside of it, rather than off an extention from the center hub. So it could stand to reason that this pulley is acting to isolate the crank "vibrations" from the accesories and accesory belt. I would offer a possible reason to run the accesory belt off the outside of a "harmonic balencer" as an effcient way too save space and gain mass for the dampening effect. I'll have to look into this to see if it is the case, rather than state my opinion as a fact.
To the argument [Quote]now here is the difference you have to look at, when the crank pulley is twisting there is no way for it to do anything else. imagine that the pulley is two pieces, under load it is already twisted to its maximum elasticity, because there is a belt forcing it stay under load [Quote] The pulley is not twisting. The crank shaft is deflecting (twisting) under the tremdous presure of the conecting rod pusing on the journal. There is a large instantainious load applied to the crank. As an example: Take a nail and a hammer and try to push the nail into a 2X4, now take the nail and strike it with the hammer with exactly the same amount of force you just attempted to push the nail in with. The nail will be driven into the wood. This same type of incredibly high, but very brief, force is acting upon the crank by twisting the metal, remember Youngs Modulus tells us the metal will elasticly stretch and rebound if enough energy is applied. Why do our cars use shocks and springs in the suspension and not just springs. It is because we need to dampen (absorb) the energy applied to the spring so it doesn't continue to bounce up and down. The shock will absorb some of the energy therby reduceing the total amount of force being applied to the car. This is how the rubber ring works. It is flexible enought that as the hammer force of the rod bangs on the crank, elasticly twisting the metal of the crank with tremendous force, the center of the harmonic balencer attempts to accelerate at the same rate as the crank, but it can not, because a mass (the outer ring) is attached to it via the rubber sleeve (shock), this aborbs the force applied to the crank by the rod. Evidence of the harmonic balencer absorbing energy is found in the article where they had to vent the balencer to keep heat down, energy absorbed as motion is being transformed into heat. I believe a pretty smart fella taught us about the conservation of energy right? I was hoping I wouldn't have to write all of this stuff up, but here it is. I guess you guys wont' let me off easy by copy and paste evidence anymore :)
I had the opinion that this pulley was a harmonic balencer long before quoting any website, the details of the thread should make that evident. I have been using the websites as evidence to attempt to prove my opinion. All the material I have come accross defines a harmonic balencer as being on the nose of the crank, with a center hub surounded by a rubber sleeve with a steel weight on the outside. Regardless of the belt being driven off the outside of the pulley, this fits every definition of a harmonic balencer. Can you quote any information to the contrary, other than your opinion?
I'm not trying to attack anyone, just trying to encourage folks to bring something solid to the table.

[ravensguildassasin]

the problem it that if you read your own statement it does fit the description, until you get to the point of it drives the belt. find me one thing that says a harmonic balancer can drive a belt. a harmonic balancer can not nor has it ever been a pulley. also by twisting i meant the rotation and force applied. as you said your self there is a large instantaneous load applied to the crank, that is also applied to the pulley making it impossible to do anything but be a pulley. for it to dampen it has to be able to move freely. in this case it cannot. i do not need to show reference material to make a point, use common sense and you will see it also. this is not advanced physics it is simple machines. i am not trying to piss you off ether so please do not take it that way.

[Tygen1]

http://cgi.ebay.com/ebaymotors/New-factory-GM-Chevrolet-1251138-balancer-belt-pulley_W0QQitemZ360052244330QQcmdZViewItem
http://www.carpartswholesale.com/parts/nissan/murano/crankshaft_pulley.html
http://www.google.com/products?hl=en&rls=com.microsoft:en-US&resnum=0&q=harmonic+balancer+belt+pulley&safe=active&um=1&ie=UTF-8

This search only took about 1 minute. Seems there are quite a number of Harmonic Balencers acting as accesory drive pulleys from pretty much every manufacture....

[Quote] also by twisting i meant the rotation and force applied. as you said your self there is a large instantaneous load applied to the crank, that is also applied to the pulley making it impossible to do anything but be a pulley. for it to dampen it has to be able to move freely. in this case it cannot. [Quote]
It seems you just don't understand the function of the rubber sleeve, it flexes under the load, not the pulley itself.
I don't take any offence at all, I enjoy this sort of back and forth. It's the "noob watcher" that tend to bug me :)

[Tygen1]

For those of you unwilling to click the link, heres a picture from the last link of a Fluidampner built Harmonic Balencer with the pulley grooves to drive an accesory belt. I hope we can all agree that the company Fluidampner knows what a harmonic balencer is :)

[iceracer]

OK, I deserve the comments on my double/triple post.
How can a pulley that has a load from a belt under tension do any balancing of harmonics ? If you look close at the Fluid damper, the pully is behind the damper. This is the case of all balncers, the belt does not go around the damper.

[Sir William]

Well Tygen1..... I guess the rest of us TZX2 members bow to your vast, albeit singular knowledge of the existence of a harmonic balancer on the Zetec engine that is in the ZX2.

And of course I'd believe "AllData" over the Online Ford workshop manual I have access to through work (Ford motor company of Canada).

We apologize for trying to make you conform to the masses misinformed way of thinking.

I see that you are unlike the rest of us "lemmings" diving to our deaths with the others.

[yellow2000S/R]

I dont have another stock pulley around here.

And BTW, that pulley I put on that 98 engine is the one from the 2000 S/R I had.

Its been too long for me to remember if it had the rubber or not.

[ravensguildassasin]

OK, I deserve the comments on my double/triple post.
How can a pulley that has a load from a belt under tension do any balancing of harmonics ? If you look close at the Fluid damper, the pully is behind the damper. This is the case of all balncers, the belt does not go around the damper.

that is the same point i have been trying to make. but my wording sucks.

[powder]

I'm gonna do you all a favor and take a torch to the stock pulley this weekend and see if it comes apart. If it doesn't, this whole argument sucks.

[iceracer]

Actually, this subject is kind of redundant. There are a lot of ZX2's running an UDP for thousands of miles with no increase in vibration,crank breakage or other related problems.

[Tygen1]

I believe we've pretty much resolved the issue of UDP not causing any problems. I am very anxious to see how Powders torch to the pulley turns out :)
If I have an S/R pulley, it is identicle to the '98 pulley, I checked carefully. I'm headed to the U-pull it today to get some other parts. I'll snap some photos of easy to see pulleys from what ever cars I pass by. I'm curious to see what is going on with these pulleys.
To iceracers point of the belt being tenstioned on the outside of this pulley. It just adds to the mass the inner pulley is trying to accelerate thru the rubber sleeve. I ought to have looked a bit closer at the Fluidampner....silly me. The fluidampner uses a viscous fluid in the pulley, so it is one solid unit. My bad :( However, how do you explain the others?
My knowledge is not singular to harmonic dampners. I know a lot of useless stuff. Any body care to discuss smog pump technology? Maybe Water Pumps? or even Vacuum Pumps :D

[Sir William]

BTW for anyone experiencing excessive vibration at idle speeds. Take a look for TSB #031515. That bulliten came out quite awhile ago dealing with excessive engine vibration.

[JonsZX2SR]

To clear some things up.

A harmonic balancer is a device which is tuned to specific frequency (+/- a range) and harmonics. It is intended to cancel out or damp a vibrational mode of a component which is independent of rpm, speed, etc. Examples are vibrations in the crank throws of the Duratec 2.5 or of some BMW 4 cylinder engines. When these modes are excited transients in the component (in this case the crankshaft) cause premature fatigue failure.

A crankshaft harmonic balanced usually contains a weight suspended from a hub through a flexible element, which could be an elastomeric ring or spring. The weight (or mass) is usually not connected to anything.

Other examples of harmonic dampers are resonators found on various intakes. They are designed to interact with and cancel out resonances in the intake runners and smooth flow over the rpm range. They also quiet the intakes.

Dampers can be filled with a viscous fluid (sometimes called fluidampers) and operate over a wide range. These are detuned or not tuned and are called anharmonic dampers.

An anharmonic or untuned damper is something that is designed to absorb and dissipate vibrations across a very wide range. If you examine the ZX2 pulley the outer ring couples to the accessory drive belt which in turn coupled to different rotating masses (generator, power steering pump, A/C compressor, etc.) and these also present varying loads.

The entire system, crank, pulley with flexible ring, belt, etc. forms a system which is able to damp transient vibrations over a wide range. It probably does more to dampen vibrations in the accessory drive, but it may reduce fatigue on the crank snout and the #1 crank bearing. Without making any measurements, I would guess the reduced load on the crank from a UDP compensates for a slight reduction of damping.

* * * * *
Aluminum is NOT a well damped material at all, and can ring or resonate as badly as most irons and steels. My experience with cast aluminum parts is they ring worse and at higher frequencies (due to lower density) than most cast iron parts. For example, cast aluminum escalator steps ring much worse than cast iron steps, requiring damping treatments.

The ability of a material to damp is the ratio of damping (loss, dissipation) modulus or stiffness (E", G") and elastic (spring) modulus or stiffness (E', G') It is usually expressed as tan delta = G"/G'. The damping factor is 2*tan delta.

Damping of most rigid cast metals is usually less than 0.001 or 0.1%, indicating a poor ability to dissipate or damp vibration. In comparison, rubber or polyurethane, even hard varieties, can have tan delta values of 0.1-0.5 or damping factors of 20-100% range. Even a hard urethane bowling ball typically has damping around 20% which is at least 100-1000 times greater than cast aluminum or steel.

[Tygen1]

Thank you JonsZX2SR. Finally someone that understands and has done some research to be sure of it :) Some of these guys think I'm a know it all and here you are talking about Delta, I thought they went bankrupt?
I took a few pics at the u-pull it. Every make I could find an exposed motor on I took a pic of. The only motor out of them all that did not have the accesorys being driven off the outer ring of the harmonic balencer was the V6 camaros. They had a pulley bolted to the center hub of the harmonic balencer. I'm too lazy to down load the pics from my camera unless. If anyone really want's to see them, let me know and I'll take the time to post them up.

[mechtech]

Ford says our damper on the crank is for accessory damping, not the crank.
At this point, this community is the expert source for crank pulleys.

[Tygen1]

If I were a wise acre, I'd say something about Ford saying the Zetec is an interference motor :D
Can you explain why accesories require dampening? I've worked on many, many cars with out damped accesories. Crank dampening I understand and has been used for a looong time. I don't understand any reason why an Alt. W/P, Power Steering Pump or A/C compressor need to be damped. The belt is already pretty flexable, added to that the automatic tensioner, how could the belt transmit enough force to damage anyone of these components.
No attack here, I am trully curious because I don't understand.

[Tygen1]

This question also just occured to me after re-reading Jons post. Wouldn't a UDP, because it not "dampening the accesories", increase the rate of failure of these components? Maybe a retorical question because no one is reporting any sort of failure associated with UDP.

[Kilroy]

i threw my stock s/r pulley out cause i screwed it up on accident, and put a 99 pulley on, there is no difference =P

[JonsZX2SR]

The damping of the accessories is to reduce noise and vibration caused by resonances in the system which might be excited by pulses from the crankshaft. Recognize the crank 'pulses' twice per rotation because the power stroke is about 160-165 deg and with a 4 cylinder engine there is only one cylinder producing torque (and therefore power) at a given time. The torque to keep the system spinning is made up by the flywheel during the remaining 15-20 deg. (This is less of a problem with 5 cyl or more engines that have overlapping power strokes, and much less of a problem with inherently balanced engines such as an I-6 or a 90 deg. V-8.)

This isn't an unusual phenomenon. An aircraft propeller blade on a wing mounted engine 'pulses' twice per rotation when it passes in front of the wing. If the propeller is rotating at 600 rpm, that means it is rotating 10 times per second. As each blade passes the wing twice per rotation, it is excited at 20 Hz. The effect is very measurable. (I've done it and solved a seal problem at the root of the blade caused by this excitation frequency.)

Since the Zetec doesn't have significant problems with crankshaft whip or harmonic vibrations that cause a fatigue problem, a harmonic damper isn't needed. The primary reason for the damping ring between the crank and the pulley is to isolate the accesory drive system from a vibration source. It isn't that any one component needs to be dampened, but system level vibrations can be excited and radiate noise at certain resonant freq., which manufacturers want to avoid.

(All of this relates to a few of my current work projects, so it's not as if I pulled much of what I share out of thin air or from the internet. I'm currently working on three projects studying noise and vibration in belt drive systems for elevators. One of the projects relates to short closed drive belts, but the other two are concerned with long flat drive belts that replaced wire ropes in elevator systems.)

The drive belt provides some isolation, but tranmission in the linear direction under tension is more effective than most people realize. The damping ring provides additional isolation.

If you can tolerate 3 to 6 dB more noise at certain freq, from the accesory drive then a solid underdrive pulley shouldn't be a problem. Powder's or any other UDP should be fine as long as the pulley firmly attaches to the crank and is concentric, the poly-V grooves match up to the belt and surface damage isn't present.

The term tan(delta) = G"/G' has nothing to do with Delta airlines, Delta faucets, etc. I spelled out 'delta' because we don't have a symbol or Greek font.

[Tygen1]

I was just kidding about the Delta terminoligy, I'm sure you figured that out :D It is refreshing to read your responce. What you have said makes sence, especially considering the lengths car manufacturers go to to for NVH tuning. Although Ford really missed the bus on the Whole motor shake :)
So would you say this dampner could/is functioning as both? I ask, because it seems that the use of this is pretty much universal among the cars I observed at the U-pull It.
I'd not be to quick to say that a harmonic dampner is not nessasary...considering the super conservative state of tune and focus on durability that manufactures also go thru to try and assure there will be no long term recalls or warenty issues. What engineer would want to be the one that recieved the blame for a recall, that engineer might call it nessesary :) I work in the automotive industry and the lengths gone thru to assure they won't have to end up in court and paying out millions is sometimes over the top. It blows me away the miniscule details that are strained after like they will be the end all of the part. Maybe Ford fell into that trap. Focusing on making a great stand alone motor but putting poorly designed motor mounts that can not handle the idle occilations.
Jons, I'm thinking you need a better avatar. Possible a giagantic bicep perched atop your head. Then the words, "Caution, Giant Brain Flexing at Work" Mine is a self portiat :)
Thanks for your input.

Power, how'd the torching go?

[Definition]

JonsZX2SR... ur a wise man..

[mechtech]

Ford could have easily used a counterbalance shaft in our engines - we have a rather large 4 cylinder to not use one.
But for costs and performance, they did not. many Dodge Neon owners[ and others] take the countershaft out of the equation to get a few more [5 HP] HP with a bit of idle vibration as the consequence.
If we had one, taking it out would be a stickied mod to gain power.
Where does Ford say we have an interference engine?

[Tygen1]

Someone made a wise crack earlier in the thread about Ford saying the Zetec is an interference motor, so I was making fun of him.
I understand about the counterbalencer, I got a Focus with a Zetec and it does not vibrate at all, that's why I was comenting on the poor design of motor mounts. Although I have no idea if the Focus has a counter balencer at all.
The use of a rubber ring on the crank pulley to dampen harmonic vibrations/frequencies in the accesory system really makes a lot of sence. However I searched the net like crazy and couldn't find anything about it. Does anyone have some reference material on this subject? Also, Mech would you be able to show the liturature from Ford saying it is to dampen accesories. I believe you, but I'd really like so see it :)
Another question that came to my mind was, "Why dont' motorcycles have harmonic balencers?" Couldn't really find any info why, although some Harelys do and other bikes from the '50's. I guess you could say the much smaller amount of total mass to resist total torsional vibration. The clutchs have rubber or spring cushions and they are directly driven off the crank, but that would not have the same effect at all because of the tolerance between the teeth on the crank gear and basket gear. I'd say pretty much all small motors (lawn mowers, weed wackers, snowmobiles, mini bikes, etc...) don't have harmonic balencers.
Possibly the answer is in the article that I pasted. It showed the amount of crankshaft twist increasing as you travel away from the flywheel. Why is that? I suppose the huge amount of mass the clutch, trans, driveshaft, axle and wheels represent are acting like a brick wall to torsional vibrations and causing them to take the next easiest route of of the crank. So maybe the lower the mass behind the motor = the less dampening required and possibly none in the case of motorcycle which has extremely low mass on both sides of the crank. I have seen a number of Chinese mini bike cranks snap the nose off, but that could be from poor metelurgy and machining.

[mechtech]

Shorts cranks don't need them, or if they are properly counterbalanced.