Can anyone explain the weird crank pulley?

[scottm]

Not the damper, but the pulley mounted to the damper. It's weird how it has the 4 spokes with a big rubber washer filling the space behind the spokes. Anyone know why it's built like that? Is it for additional vibration damping on the accessory drive? ATI will make me a neutral-balanced damper from a bbc damper for my theoretical high-rpm and internally balanced 6.5 diesel, which I would have to adapt a regular crank pulley to fit. But now I wonder if the stock 6.5 pulley is designed to do something special, or if it is just weird for no good reason..

 

[schiker]

To absorb any pulses from the Diesel harmonics is what I have always heard. The 6.5 tends to stretch out a serpentine belt pretty quick if its not high quality.

 

[ak diesel driver]

from a conversation I had with a fluid damper tech, to get the proper order of the conversation start at the bottom


Les,

There wasn't any link in the email you sent. We do make a couple non-sfi dampers for other applications but honestly we don't sell very many at all. With the performance diesel dampers, it is better to use a SFI rated material as the horsepower/torque of the vehicles works the damper pretty hard. Using a non-SFI steel "may" compromise the structural integrity of the damper, we have never tried it but I am just assuming it may not be strong enough.

Paul @ Fluidampr



-----Original Message-----
From: Les
Sent: Thursday, April 19, 2012 4:46 PM
To: Paul Bennett
Subject: RE: Fluidampr.com Tech Support Request

Here is the link to the thread I posted it in. It's too bad you guys don't make a non sfi rated damper. The lesser price of the non rated one would probably double or even triple their sales as the aftermarket one from the parts stores are pretty much junk, even the OEM ones are made in China now.

-----Original Message-----
From: Paul Bennett [mailto[email protected]]
Sent: Thursday, April 19, 2012 9:51 AM
To: Les
Subject: RE: Fluidampr.com Tech Support Request

Sure,

Post a link if you can, I would be interested to see the article. The pulley is a OEM GM part, and I am no GM engineer but from what ive researched in the part, that's the information I found.

Paul



-----Original Message-----
From: Les
Sent: Wednesday, April 18, 2012 4:04 PM
To: Paul Bennett
Subject: RE: Fluidampr.com Tech Support Request

Do you mind if I post this on a forum?

-----Original Message-----
From: Paul Bennett [mailto[email protected]]
Sent: Wednesday, April 18, 2012 11:26 AM
To: Les
Subject: RE: Fluidampr.com Tech Support Request

The rubber that is inside of the pulley acts more as a torsional spike reducer. This makes sure the belt does not slip or chirp when it's running.
The rubber in the pulley serves as a decoupler mostly, but does not serve much use in reducing engine torsional vibrations. Hope this clears things up.

Paul @ Fluidampr




-----Original Message-----
From: Les
Sent: Tuesday, April 17, 2012 4:36 PM
To: Paul Bennett
Subject: RE: Fluidampr.com Tech Support Request


Thanks for the reply. So what would you say the purpose of the rubber in the accessory pulley if for, shock loading??

-----Original Message-----
From: Paul Bennett [mailto[email protected]]
Sent: Tuesday, April 17, 2012 12:27 PM
To: Les
Subject: RE: Fluidampr.com Tech Support Request

Les,

Sorry for the delay, I was out of the office for surgery. I am not sure if you called the office or not while I was gone but I'll try my best to answer your question.

The accessory pulley is part of the damper, but it does NOT function in any way to dampen vibrations. Its only purpose is to drive the belts. Like I said in my previous email, some pulleys are removable while some are machined into the housing as 1 unit. The pulleys are machined to strict tolerances as to make sure there will be no wobbling of any sorts.

Hope this helps,

Paul





-----Original Message-----
From: Les
Sent: Wednesday, April 11, 2012 2:05 AM
To: Paul Bennett
Subject: RE: Fluidampr.com Tech Support Request

I understand that I need to use my oem pulley but you didn't answer my ?. Is the accessory pulley, which has rubber isolation built into it considered part of the harmonic balancer system?

-----Original Message-----
From: Paul Bennett [mailto[email protected]]
Sent: Tuesday, April 10, 2012 12:26 PM
To:
Subject: RE: Fluidampr.com Tech Support Request

Les,

Thank you for contacting Fluidamr's tech support.

Depending on the application/engine, the serpentine belts will vary. Some of our dampers have serpentine/v belt grooves while others do not. Our 6.5 chevy damper does not come with belt grooves, you will use our OEM pulleys/belts on this application. If there is anything else I can help you with please feel free to ask.

Thanks,

Paul @ Fluidampr




-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Monday, April 09, 2012 4:54 PM
To: Ivan Snyder; Pete Dandrea; Paul Bennett
Subject: Fluidampr.com Tech Support Request

First Name: Les

Last Name:

Email:

Phone:

Engine: chevy 6.5 diesel

Comments: was wanting to know if the accessory belt pulley that bolts to the harmonic balancer is considered part of the harmonic balancing system?

Engage: Submit

Redirect: THANKYOU.htm



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[scottm]

The pulley mounts directly to the inner hub of the damper, so it makes sense if the spokes are there to protect the belt and accessories from crank vibrations and shock. That protection will not be there on aftermarket dampers with built-in pulleys. As anyone with a fluidamper noticed shorter belt life?

 

[ak diesel driver]

I read that differently. the rubber in the crank pulley is used to dampen the accessories

 

[3500GMC]

Has anyone with a fluidamper noticed shorter belt life?

I've noticed the belt doesn't flop around on the slack side as much. Running the 4 spoke dampened pulley and 6.2/5 spec FD.

 

[scottm]

Does anyone have a FD damper with the built-in pulley?

 

[3500GMC]

Have not seen such an animal on a 6.2/5. All are the same on these. One difference is the spacer if you are mech inj. Takes the place of the reluctor.

 

[turbovanman]

The pulley mounts directly to the inner hub of the damper, so it makes sense if the spokes are there to protect the belt and accessories from crank vibrations and shock. That protection will not be there on aftermarket dampers with built-in pulleys. As anyone with a fluidamper noticed shorter belt life?

I installed a FD years ago and the first thing I noticed was belt wrap/movement was big time reduced, my belts are living longer which is great as the quality has taken a nose dive.

The pulley on the 6.5 is to dampen the sudden acceleration/decel of the belt due to the firing order and harmonics, hence why V belts don't last long.

 

[Chevypoor]

I agree on the belt. My understanding was to help with belt harmonics... have heard the older non serpentine 6.2s will throw a belt in a heartbeat.