Dynamic dampening front pulley

nkaminar

nkaminar

Well-known member
Has anyone tried installing a dynamic dampening front pulley. I am trying to reduce torsional vibrations under certain conditions for my engine. A dynamic dampening pulley is used on modern engines. It has a viscus or rubber coupling to a heavy pulley that absorbs torsional vibrations. They were first used on straight 6 and 8 cylinder engines to eliminate broken cranks.

I have located a dynamic dampening pulley from a company in New Zealand, photo below. I am trying to decide whether to buy it or not.
 

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I should add that it is a direct replacement for the standard pulley without modification to the engine.
 
I have fitted one on an engine I haven't driven without the Dynamic Balancer so comparison is a little difficult. I have, however driven many other Model As over the years for comparison. I believe it has made a difference - this is my smoothest running (of 4) engines. Would I do it again? Yes!
BTW, the pullies come with an option. For those with the original ripe style front seal, there is a reverse scroll machined into the pulley available to help reduce leakage. For those with the modern style seal, the pulley is plain for the seal to seat against.
The only negative I can give is they are a little closer to the front cross member which means fitting a fan belt will take a little fudging.
 
I agree with Synchro909, the pulley did make a difference on my engine which had harmonic vibrations at 1500 and 2200 RPMs before I installed the pulley. Like Synchno909 said, installing a fan belt becomes a bit of a chore.
 
There are a couple of threads on 'Harmonic Balancers' or 'Vibration Dampers'. I have one on my Town Sedan. I believe it works well for what it is designed for but if you have an engine that is out of balance the Harmonic Balancer is not going to cure your vibrations.

I use a segmented belt with my HB so I can get it off or on while on the road. The segmented belt also seems to help some with vibrations.

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Murray Horn.. email horn@extra.co.nz..

A nice balancer, quality unit and a good man to do business with.. torsional vibration has a 'tuning fork' effect. Herm Kohnke felt that the torsional vibration caused a .001 deviation at center main at 2400rpm.I figure the pain of belt replacement a small price for extended bearing life.
 

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Thank you all for you comments. Based on what people have said, I am going to order the pulley. I will report the results to the forum with I have it installed in a few weeks.
 
That pulley may help a very small amount. It is no where near heavy enough to really do any good though. In theory the front pulley needs to be as close to the flywheel/clutch weight as possible for maximum torsional vibration dampening. This is not possible in the real world but in some cases of race engines it can be close and definitely helps.
The heavier the damper, the better.
Here is a pic of a 12 lb. big block Chev one adapted to a B circle track engine.
 

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Y-Blockhead said:
There are a couple of threads on 'Harmonic Balancers' or 'Vibration Dampers'. I have one on my Town Sedan. I believe it works well for what it is designed for but if you have an engine that is out of balance the Harmonic Balancer is not going to cure your vibrations.

I use a segmented belt with my HB so I can get it off or on while on the road. The segmented belt also seems to help some with vibrations.

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I’m curious. Where did you purchase your segmented fan belt? I looked online and didn’t see any obvious site offering them. That would be handy to keep in the car.


Sent from my iPhone using Tapatalk
 
Many flavors except licorice. Harbor Freight has lime.


Sent from my Western Electric crank phone on my kitchen wall using Crankatalk.
 
Use a standard black fan belt and keep a rainbow belt under the seat for emergency to get home. If you have the extra belt with you Murphy says you will never need it!
 
It takes a little persuasion but I was able to work a B belt under the balancer., to me its a small price if the balancer saves bearings.
 
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