Harmonic balancer /crank damper mods

[bhearts]

Got this big nose crank in the mail from a fellow member. I wanted to buy an ati damper this time for my build but for the sake of never ending money spending, I'm using the factory pulley. The serp pulley has those 8 slots in it that indicate big nose, and behind them it's hollow. Are you thinking what I'm thinking? If guys buy lightened pulleys and flywheels and that's the worst possible thing you could do for your harmonics, then adding weight to them should be the best as long as it's balanced. I'm thinking about filling the serpentine pulley with some sort of weight additive, maybe a really light weight and flexible silicone rubber material. Whats anyone think about it?

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[azgtx]

I am sure Chuck will chime in on this one...in harmonics is his specialty..among others.

[bhearts]

Who's Chuck, paging Chuck

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[azgtx]

Charlie lol

[bhearts]

Charlie lol

O, lol

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[bhearts]

Could you imagine revving a b6ze to 8k. I wonder if the cam profile would support that rpm

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[ryanprins13]

Harmonic balancer /crank damper mods

What materiel would you plan to use? Most silicon i know of does not adhere to metal very well on something that gets stressed. You dont want it coming off. Are you thinking a shore A rubber? a shore D urethane will probably shrink too much to adhere well. If it shrinks at all it tends to pull away from the metal. You would have to clean the pully with solvent, then sand it with course (like 40grit) sandpaper to give it something to adhere to. You would have to plug all the holes evenly which would be easy, then when you fill it it would have to sit perfectly and absolutely level. That would be harder. Even the very slightest tilt would result in one side being heavier.
What about melting lead and pouring it in? I have never done anything with lead, it may cool too fast to flow out evenly. You can get aluminum filled urethane that is heavy, but it still shrinks a bit. I think you need to go with something heavier. How many cc's or cubic inches will this take? I think most silicons and urethanes are only about 1.1-1.3 grams/cc. How much weight do you want? I would think lots. You can get adhesion promoter for metal that is meant for urethane to metal bonding if you want to use a shore D urethane and are worried about it shrinking away from the metal. I wouldnt use anything that shrinks more than 0.005inches per inch. Look for something that has a really long demould time. In general the longer the demould time the less shrinkage. Something longer than 4 hours probly.


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[bhearts]

What materiel would you plan to use? Most silicon i know of does not adhere to metal very well on something that gets stressed. You dont want it coming off. Are you thinking a shore A rubber? a shore D urethane will probably shrink too much to adhere well. If it shrinks at all it tends to pull away from the metal. You would have to clean the pully with solvent, then sand it with course (like 40grit) sandpaper to give it something to adhere to. You would have to plug all the holes evenly which would be easy, then when you fill it it would have to sit perfectly and absolutely level. That would be harder. Even the very slightest tilt would result in one side being heavier.
What about melting lead and pouring it in? I have never done anything with lead, it may cool too fast to flow out evenly. You can get aluminum filled urethane that is heavy, but it still shrinks a bit. I think you need to go with something heavier. How many cc's or cubic inches will this take? I think most silicons and urethanes are only about 1.1-1.3 grams/cc. How much weight do you want? I would think lots. You can get adhesion promoter for metal that is meant for urethane to metal bonding if you want to use a shore D urethane and are worried about it shrinking away from the metal. I wouldnt use anything that shrinks more than 0.005inches per inch. Look for something that has a really long demould time. In general the longer the demould time the less shrinkage. Something longer than 4 hours probly.


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I was thinking something like a window weld, which is what lots of folks use to fill motor mounts. But you're using names of stuff I'm not familiar with at all. But lead has selling points to me, that's heavy

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[bhearts]

If you look at the cutaway of a damper product like fluidamper, they don't have insane amounts of fluid rubber material in their products.

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[bhearts]

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[ryanprins13]

I was thinking something like a window weld, which is what lots of folks use to fill motor mounts. But you're using names of stuff I'm not familiar with at all. But lead has selling points to me, that's heavy

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Ok, never heard of it. As long as it adheres good and flows well. Something that glues windows sounds like it should adhere well. Have a look at the products for sale on this website. https://bjbenterprises.com
Maybe not what you need or want but its what i was thinking.

If you look at the cutaway of a damper product like fluidamper, they don't have insane amounts of fluid rubber material in their products.

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Ok, but are they after the exact same thing you are or just something close? Also it may not be a lot of fluid but what is the density of it? That can make a big difference.

[ryanprins13]

Did you end up trying this?


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[Advancedynamix]

The ATI product uses rubber O rings. The math is in the weight of the damper and the diameter. I wish I was a master of harmonics. I only know enough to understand the critical results of excessive harmonic forces.
I'm not even sure what frequency is responsible for the damage to the b series oil pump, but I know that the factory pulley is tuned to reduce that frequency. If you install a lightweight aluminum main pulley and run the engine hard over 5500rpm you are in great risk of shattering the oil pump.
The trick is to know what frequency that your trying to eliminate and then knowing how to do that.
My good friend Johnny West once told me, "save your ass with mass" when I asked him how they put down 6+ thousand HP in the funny cars without exploding the hardened gearsets in the rear end. They try to shave weight wherever they can on those cars, but the gearsets are not the place to shed a few pounds. In recent years, the gears have been made heavier than in the past.
One thing to keep in mind. You don't want to pour hot led into that balancer. It has bonded rubber inside it already and the heat will ruin the damper.

[Dragonhealer]

Charlie was kind enough to lend us a Miata calibrated ATI damper for testing on our 8200rpm engines.
it works well with the "O" ring durometer supplied, main bearings at the front have the least wear.
if anyone needs hydraulic 1600 cams that will support 180hp, feel free to PM, our testing normally asperated is done

[Advancedynamix]

That is awesome news Ryal. I'd like to do a write up on some of your development in the near future. With respect to your trade secrets of coarse. Many people would seriously question a 180hp NA b6 that's still running on factory fuel injection, but I've seen and driven these engines myself and this is no B.S. Ryal is a wizard.