Stock harmonic balancer information, heat and other data that may be usefull..

[meminto]

Hi all, As I am quite specific about data and information, a recent post about powdercoating and the affect heat may have on the rubber within the balancer, has provided the oppurtunity for me to gather some information that others may use as they please

All measurements are in millimeters, oven is fan forced and set at 260 degress celcius (500 f)...

First off, here is the stock balancer, this one is quite dead, however the rubber dampener was still in quite good condition. The material is soildly attatched to the balancer, was very difficult to push in with a blunt object and has very minimal elastic properties..



As you can see, the crank has made a lovely imprint in the balancer itself, so a measurement is easily obtained referring to the diameter present on the balancer...



The thickness of the dampening material is plainly visible in this shot...



The OD of the dampening material, you can work out the ID of the material using the thickness and OD figures..



I used a small drill bit to measure the depth of the material, I have found the balancer is solid, with the material not as deep as the balancers height. One thing I noticed was I had to apply a slight downforce to the drill to drill through to the end of the material, so the material itself seem rather solid..



And this is the balancer as it went into the oven, as I write this it has been in there for 55 minutes to simulate the heat of powdercoating, I will be taking it out when it hits 1:15..



Conclusion shortly...

[themadscientist]

Holy crap, pull it off with a sledgehammer?

Every one I pull on CAs and RBs is chipped up on the edges like that.

THIS is what I like, this kind of "drop the BS and let's test this" activity. These are the things that seperate speculation from hard evidence and thank you for doing the work.

We should have set up betting though, what's Vegas saying on this?

[meminto]

Okie Dokie..

Out of the oven and here is the first shot, so far I have noticed that the material itself has raised about 1.5mm from its original postion and there is some surface cracking, which looks to be about maybe two or three thou in depth. When you consider the thickness of the material this is absolutely negligable..

There is no difference in the elasticity test I performed, no bubbling, no melting, no detatchment from the balancer, its almost come out how it went in...

As I let it cool at room temp which is currently 31 degrees celcius in the QLD Aussie summer, the material is slowly recessing and taking its original form...



I will edit this post once its completely cool...

and lol @ TMS...

Ok here is the result...

After 3 odd hours of cooling, it is back to room temperature. The first thing I noticed is the material was still raised 1mm from the original position, this would be a result of the heat. The surface fractures in the material did not get larger or smaller during cooling.

These fractures I believe are a combination of the heat and the age of the material, however as they are very small in depth they are not of any concern, if they were say 5-7 mm in depth it may have been a very different story..



I got out the drill and drilled into the material in two places to check the depth, the depth increased 1mm, due to the raise in the material. I then drilled in two locations so I could retrieve a sample of the material. It was quite difficult to cut out as it was still firmly adhered to the surrounding casing. I had to remove some more material to the left of the sample I took so I could physically remove it lol...



The sample I wanted is the square above the triangle piece (the triangle piece was the bit i hacked up without care to remove the square sample). As you can see there are still casting marks in the rubber, as I do not know how the balancers were made in the factory, to me it looks as though it may have been some sort of injection moulding, but only speculation....



As you can see the material does have some elasticity, even after many years of operation and a bake in the oven, it is not so brittle..



I cut away approx 4mm off the top of the material, this was still quite difficult as it was firmly attatched to the outer casing, I did my best to obtain a smooth cut, but it was near on impossible...



I hope this provides some useful information on the balancer for the folk out there looking for it

Thanks to niscort for providing the cross section cut of the balancer...

Cheers...

Modified by meminto at 8:59 PM 1/24/2009
Modified by meminto at 9:02 PM 1/24/2009

[themadscientist]

Us Americans will bet on anything. They take side bets on the coin toss at the superball for crying out loud; heads or tails, 50/50 action.

[niscort]

fwiw

stock pulley

I see your pov thumb and raise you

[meminto]

Crazy lot you guys are... Side bets on the coin toss lol....

[meminto]

Nice one on the balancer cross section, yeah but my povo thumb is from me biting the nail down so self inflicted

But my birdie finger looks like yours at the moment

[themadscientist]

I was going to mention that knarly finger of yours.

[float_6969]

That cross section surprised me. I assumed the pulley was isolated from the crank via the rubber dampener. I didn't expect to see that the crank is directly running the accessories, and the dampener is simply attached to the crank pulley on the inside.

[bentvalves]

the rubber bulging 1mm after a 500 degree F oven bake would be enough for me to warrant the pulley totaled.

im sorry thats how I see it? because you seem to be getting rather upset about me voicing my opinions in your other thread.

[meminto]

Fair call, if you believe so your perogative..

I had no problem with you voicing an opinion, but you had absolutely no data to back up your opinion...
Modified by meminto at 3:48 PM 1/25/2009

[themadscientist]

That cross section surprised me. I assumed the pulley was isolated from the crank via the rubber dampener. I didn't expect to see that the crank is directly running the accessories, and the dampener is simply attached to the crank pulley on the inside.

If the pulleys were isolated from the crank the elastomer would deflect under the load of the belts on the pulley. The front section also needs to be free to vibrate so it can actually dampen.

[zero_gripS13]

thanks for the info, and all the work. glad to atleast have this info available as any info is good info.. i will reusing my oem balancer id like to get a new oem one or the ross one but its out of my budget.

[float_6969]

If the pulleys were isolated from the crank the elastomer would deflect under the load of the belts on the pulley. The front section also needs to be free to vibrate so it can actually dampen.

I thought of that, but I also thought that was part of it's purpose. Especially the A/C when it kicks on and off, I would think that would put a pretty decent shock load to the crank, and part of the pullies purpose was to dampen that. Apparently not.

What do you mean by the last part?

If the pulleys were isolated from the crank the elastomer would deflect under the load of the belts on the pulley. The front section also needs to be free to vibrate so it can actually dampen.

[themadscientist]

Well the idea of the elastomer balancer is to cancel out the vibrations of the crank. In order to do that when the crank flexes one way something must go the other way in an equivalent fashion. That would be the ring that floats freely. When the pulley vibrates to the left the ring that is not firmly attached and wants to continue spinning as it has been can stay centered and resist it. The elastomer compresses as the crank tries to pass its movement to the ring dampening the vibration. It functions like a 360 degree shock absorber. In much the same way a shock controls suspension movement the balancer brings crank movement under control.



If it was encoumbered with a pulley than the tension of the belt would deflect the ring on the elastomer and prevent it from vibrating freely so it could not do its job. It would just vibrate with the crank making the situation worse as yet more mass would be out of balance.