<VV> Fwd: Harmonic Balancer / Solid Pulley on 140

[Ken Pepke]

It is true that Corvair engines are NOT externally balanced.  Corvair balancing consists primarily of getting all the like reciprocal parts to weigh the same.  Rotating parts are balanced to turn about their center.  The majority of Corvair dynamic balancing comes from its opposed cylinder design.  It has been suggested there is a magical point of 4300 in the RPM range where the harmonic balancer becomes effective.  In reality, harmonics run through the whole RPM range like a sine wave.  There is a degree of stress added to the internal parts even if the driver cannot hear or feel the vibrations.  Apparently, GM thought to save a little money on certain low performance / low option models by equipping them with the inertia pulleys.  Fact is, it was an 'accounting' improvement rather than an engineering improvement.  

Corvair owners have long been accused of being cheap; some even brag about it.  Perhaps some are so proud of their 'cheap' status they might employ the inertia wheel / pulley to demonstrate their devotion to that principal.  But, why on earth would any real 'car enthusiast' even think about choosing such a substandard part?  

As for externally balanced engines [such as 454 Chevies, etc.] that have mass added to part of rotating mass of the harmonic dampener and flywheel, the first step by any serious engine builder is to rework the engine to INTERNAL balancing.  They ALL use a harmonic balancer and NOT an inertia wheel in these applications.

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

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

> From: Frank DuVal <corvairduval at cox.net>
> Date: June 12, 2011 9:31:26 PM EDT
> To: virtualvairs at corvair.org
> Subject: Re: <VV> Harmonic Balancer / Solid Pulley on 140
> 
> Rodney, while there is nothing wrong in your approach, it goes waaayyy 
> over the top for most Corvairs. GM never balanced the harmonic balancer 
> for use with only one set of crank, rods, etc. They were replacement 
> items from the parts bin at a dealer. Each balancer was balanced when 
> made to itself. So every balancer is exchangeable on any engine without 
> upsetting balance. Unless you have drilled the balancer on a particular 
> engine to improve things, then when your balancer fails, you must start 
> all over again with all the separate parts. Way too much work.
> 
> Same with Corvair flywheel. It should be balanced to itself, not to 
> correct internal parts imbalance. The next clutch job and you will have 
> to start all over again. I have my flywheels balanced after I replace 
> the rivets with bolts.
> 
> Corvairs are not externally balanced engines. Some others are.
> 
> Maybe I just didn't understand your comment?
> 
> Frank DuVal
> 
> On 6/12/2011 12:00 PM, Rodney Sampson wrote:
>> I'd only use on an engine that's been balanced with the rest of the engine components.
>> When I send my motor out to be balanced, pulley, crank, pistons, rods and flywheel
>>   go.
>> 
>> Thanks
>> Rodney Sampson
>> HACOA
>> 
>> Message: 9
>> Date: Sun, 12 Jun 2011 11:49:00 EDT
>> From: HallGrenn at aol.com
>> Subject: Re:<VV>  Harmonic Balancer / Solid Pulley on 140
>> To: hennerfeind_joe at yahoo.com, virtualvairs at corvair.org
>> Message-ID:<143a5.72fa9318.3b2639ec at aol.com>
>> Content-Type: text/plain; charset="US-ASCII"
>> 
>> 
>> In a message dated 6/12/2011 9:12:46 A.M. Eastern Daylight Time,
>> hennerfeind_joe at yahoo.com writes:
>> 
>> I picked  up my 140/manual that I am going to install in my 110/PG car and
>> noticed the  harmonic balancer is probably on its last leg.  With cost in
>> mind, what  is the concensus on putting a solid pulley on it?  The 110 I am
>> pulling  has a solid pulley.  Thanks again, Joe
>> 
>> 
>> 
>> The extra cost of the harmonic balancer was warranted to protect the lower
>> end from harmonic vibrations that could damage or destroy the crank and/or
>> bearings according to my information.  My local Chevy dealer put a solid
>> one on my '68 110 Monza 4 spd in the early '70s that I removed a few months
>> later because I could feel a roughness when the engine was revved to the
>> upper  RPMs.  The good, used harmonic balancer I got from a junk yard and
>> installed cured the issue.  I later learned that GM's engineers specified  the
>> harmonic balancer for this reason (as they did on other GM  engines).
>> 
>> Bob Hall
>> Group Corvair
>> Corvanatics
>> 





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