<VV> Re: [FC] [VV] Harmonic balancers....

[corvairs]

All rotating shafts set up harmonic distortion - The distortion has peak 
points where damage is accumulated. The reason the early Corvairs do not 
need it is because the harmonic distortion points are not reached in 
normal rotation (Let's just say, for example, the first peak distortion 
point would be 6,000 rpms - obviously not an issue).

When the engine was stroked in 1964, a number of factors lowered the 
peak point(s) into normal operating range. Not just the additional throw 
itself (because then why would the same cu 95hp engine not need a 
balancer?)  but also changes in the force due to the increased horsepower.

It seems possible that if you made substantial hp modifications to an 
early 145 cu motor that you might end up with distortion issues under 
normal rpms - but that has never been researched or proven. Putting a 
balancer on an early motor won't hurt anything, but costs extra money 
and could be a maintainance problem down the road (unless it's a dale 
balancer of course).

The argument is that GM and everone else putting these much more 
expensive balancers on millions of engines would not have done it if it 
wasn't  necessary. Sometimes modern technology  can prove that such 
things were unnecessary. But that doesn't seem the case here. It's 
pretty hard to get away from real physical properties of rotating 
shafts. If anything, someone may develop a much cheaper, easier way to 
mitigate the problem. But, for Corvairs at least, that hasn't happened.

Lon
www.corvairunderground.com

Rick Loving wrote:

>Has any thought been applied to using or not using HB on larger than
>164cu motors?
>
>Was it the longer throw of the stroked motor that required the HB?
>
>If you stroke a 164 motor, will the stock HB still function? Would the
>harmonic's and damping effects still cancel themselves out?
>
>Rick Loving
><SNIP>
>
>
>Subject: <VV> Re: [FC] [VV] Harmonic balancers....
>
> 
>In a message dated 6/29/2007 7:49:57 PM US Mountain Standard Time,  
>noahsarkinc at earthlink.net writes:
>
>If it  isn't broke, then why mess with it.  The balancers were
>neccessary 
>when  GM went to the larger displacement engines to smooth out
>vibrations.  If  
>you don't have a problem, why spend the money?  Paul in  CT
>
>
>
>Paul,
>With all respect, I must disagree with you here. The Harmonic  Dampers
>are 
>there to dampen the torsional vibrations caused by the power  stroke
>impulses 
>twisting the  crankshaft and causing oscillations of  the crank. They
>are really 
>not balancers but are dampers. These dampers  were necessary on all 164
>CID 
>engines. The problem is that running without a HD  causes minute cracks
>to 
>develop in the crank, and then grow each time undamped  oscillations
>occur. These 
>cracks expand and grow for each occurance of the  undamped oscillations,
>until 
>one day the crankshaft just breaks in two.  By  then it's too late to
>fix the 
>problem. So while you might think there is no  problem prior to a crank 
>breaking, you will know for sure you have a problem  after it does. My 
>recommendation is to always run a HD on a 164 CID  engine....ALWAYS.
>Regards,
>Bob Helt
>_____
>
>
> _______________________________________________
>This message was sent by the VirtualVairs mailing list, all copyrights are the property
>of the writer, please attribute properly. For help, mailto:vv-help at corvair.org
>This list sponsored by the Corvair Society of America, http://www.corvair.org/
>Post messages to: VirtualVairs at corvair.org
>Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs 
> _______________________________________________
>
>
>  
>