<VV> Response to Harmonic lab sheets from GM on Dale MFG. website

[Paul Fox]

So what type of rubber and or hardness is used to rebuild a damper can make a big difference? What about fluid type of dampers?
Paul Fox (so far no broken cranks)
--- On Tue, 6/14/11, Ken Pepke <kenpepke at juno.com> wrote:


From: Ken Pepke <kenpepke at juno.com>
Subject: <VV> Response to Harmonic lab sheets from GM on Dale MFG. website
To: "Vair Views" <virtualvairs at corvair.org>
Date: Tuesday, June 14, 2011, 7:40 AM



Too bad the charts are not so easy to read, at least for my eyesight.

Most interesting assessments!  I wonder at what point in time these tests were made?  It look like the year says 65.  Bob Kirkman would have been a fountain of knowledge had we thought to ask.

First item of interest to me is the limited number of peaks and valleys throughout the RPM range.  Far different from the V8 results ... but that may be because of the basic engine design.  After all, the Corvair crank does not have the heavy counterweights of the V8.

Also of interest is the WOT #3 spike at around 1500 RPM. And the somewhat lower magnitude spike just shy of 2800 RPM in test WOT 6.  This may well be the basis for Smitty's memory of a 2700 RPM danger point.  

>From the Text:
"..Our own testing of used GM harmonic balancers has shown that as the factory rubber begins to harden with age and temperature, the tuned frequency of the harmonic balancer increased as much as 26% with the unit still appearing to be intact and serviceable."

For some strange reason with as many times as I have durometer tested the rubber in both Corvair and V8s I have not come across one that was harder than new out of the box, with the softest reading coming from a failed unit.  I have scrapped units with low readings in the belief they could be too close to failure.  Perhaps my simple test is somehow invalid ... not sure how or why. 

It would be really interesting to see similar charts using the solid inertia wheel pulley.

Ken P
Wyandotte, MI
Worry looks around; Sorry looks back, Faith looks up.

***************************

> From: Matt Nall <patiomatt at aol.com>
> Date: June 14, 2011 12:31:15 AM EDT
> To: virtualvairs at corvair.org
> Subject: Re: <VV> Harmonic lab sheets from GM on Dale MFG. website
> 
> 
> for some reason this was just posted over on FastVairs....
> 
> 
> 
> http://www.dalemfg.com/harmonicbalancer_008.htm
> 
> 
> Matt Nall
> Charleston, Oregon
> http://mysite.ncnetwork.net/reswr0kp/





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