Aluminum Crank Pulley ?'s

[high-psi-tsi]

Hey guys,
I jsut stumbled upon a great deal for a aluminum crank pulley. Mine stock one is pretty shot so I'm seriously considering picking this up. Could running it have any negative affects upon my engine? Thanks

 

[turbo90gsx]

Does it have a harmonic damper on it?

 

[high-psi-tsi]

nope

 

[4GSixty3]

not good...

 

[turbo90gsx]

Is your motor fully balanced? Cause I heard some grousome stories about no dampers, or dampers going bad. If it doesn't have a harmonic damper I myself wouldn't put it on my car. Any other opinons out there?

 

[Bluebyu96Tsi]

fully balanced motor, Maybe. Unbalanced motor, not for me thank you. Your bearings would not appreciate that vibration. I have a fully balanced rebuilt motor and i still would be scared to pull one of those things on. Vector sells a lightweight crank pully with dampering but its very price $350, but in my opinion thats the only way id go Wish you luck with it though if you decide to pick it up

 

[Car Cannibal]

Regardless of if its balanced or unbalanced, not running a dampener is a horrible idea. The vibrations multiply as it travels towards the opposite end of the crank. With most DSM's turning 7,500 rpm with no problem, not running a dampener makes for some crazy crank vibrations.

I would only do the water and alt pulleys to save some reciprocating weight.

 

[4wd-Eclipse]

Hey guys,
..... Could running it have any negative affects upon my engine? Thanks

See this:
http://dinan.tempdomainname.com/html/danger_of_power_pulleys.htm

 

[high-psi-tsi]

Thanks guy for the quick replies. You may have saved me some serious engine damage. It may be worth considering machining my own with a dampener built in if the cheapest one out there is $350

 

[JiveMasterT]

i to thought about getting one of those solid ones because my crankshaft pulley split in half (luckily no damage) but i guess its better to just keep an eye on that pulley than have your motor explode on your because a bearing siezed because there was too much vibration.

 

[doug]

I don't get it. There's a thin strip of rubber around the middle of the stock crank pulley that supposedly absorbs vibrations or whatever. Wouldn't the timing belt and accessory belts also absorb these allegedly "dangerous" vibrations too? I'm just not convinced about the whole harmonic dampening thing, especially on comparatively short (as compared to the ones in the Dinan article) 4-cylinder crankshafts like ours.

Like I've mentioned in several threads, I've been using a one-piece aluminum crank pulley for about three years. I haven't had any weirdness or problems so far, but I'd be curious to tear the engine down and see for sure. I'll be selling this car in about a year anyway, so I doubt that'll happen. Another thing that I know won't happen is the stock pulley separating and causing all other kinds of damage.

 

[JiveMasterT]

I don't get it. There's a thin strip of rubber around the middle of the stock crank pulley that supposedly absorbs vibrations or whatever. Wouldn't the timing belt and accessory belts also absorb these allegedly "dangerous" vibrations too? I'm just not convinced about the whole harmonic dampening thing, especially on comparatively short (as compared to the ones in the Dinan article) 4-cylinder crankshafts like ours.

Like I've mentioned in several threads, I've been using a one-piece aluminum crank pulley for about three years. I haven't had any weirdness or problems so far, but I'd be curious to tear the engine down and see for sure. I'll be selling this car in about a year anyway, so I doubt that'll happen. Another thing that I know won't happen is the stock pulley separating and causing all other kinds of damage.

it doesnt make sense that it would damage your motor with the vibrations, but ive heard of people's motors getting totally fubar after having one of those thigns on there, especially high revving motors.

 

[Car Cannibal]

Thats an informative article.

I think Eric at AMS installed a crank pulley and not to long after he busted his crank. I wonder what rod had the most damage or where it broke? Maybe he will come on here and say.

I think the damper is to small on these cars and could use an aftermarket piece to absorb more. I would of bought one of these but they are not available for us.

Check out these links
http://www.fluidampr.com/problem.htm
http://www.fluidampr.com/testresults.htm ( this is just to show how much more it can absorb over another good aftermarket damper ).

My factory damper seperated from the pulley on start up one night, totally sucked. But this motors trashed already with the fuel problems I had with a bad fuel pressure gauge so maybe I will look into getting one made for us. I know I will need one in the next year or two after the rebuild.

 

[Defiant]

I don't get it. There's a thin strip of rubber around the middle of the stock crank pulley that supposedly absorbs vibrations or whatever. Wouldn't the timing belt and accessory belts also absorb these allegedly "dangerous" vibrations too?

Not well enough. The coupling and weight are figured out by guys who do math. There's more to it than absorbing vibration, it's also returning windup.

 

[Eagle 5]

heres one way of looking at it. take your engine mounts for example. Your engine makes lots of virbations, and ALL the mounts are rubber. The rubber allows the engine to move some and they absorb some of the vibration from the engine. When dampening (as engine mounts do) is put on something, the peak or max amplitude is decreased, however the vibration is spread out over a longer period. When you replace the rubber mounts with solid motor mounts. Your dampening (yes technically dampening is not a word but whatever) value is decreased significantly. The peak or max amplitude value goes WAY up, but the vibration dies off much quicker than with dampening. Dampening is based on the velocity of something. basic formula for vibration is

ma + cv + kx = f where m = mass, a = acceleration, c = dampening coefficient, v = velocity, k = spring stiffness, x = distance, f = forcing force.

solid mounts make the c value very small. that rubber in your harmonic damener has a higher c value than a solid one letting it abosrb more of the vibrations. going with a solid one makes your vibration amplitude much higher. Guys with solid motor mounts know how the vibration feels and how bad it can be, usually only for a short rpm range though.

There is more to this but im at work and cant go too in depth. If I get time ill post up some pictures later of some graphs to help explain this and also throw in some stuff on natural frequencies and such.

 

[doug]

I would of bought one of these but they are not available for us.

Check out these links
http://www.fluidampr.com/problem.htm

Actually, I e-mailed them just the other day and they said they have a 4G63 model in the works and should be available in a couple of months.