<VV> Harmonic Balancer

[Hugo Miller]

That's got to be over 100mph, isn't it?

On 2020-03-21 23:39, James Davis via VirtualVairs wrote:
> If you look at the initial SAE engineering paper, the 140 cuin 
> Corvair
> engine showed a huge crankshaft resonance at around 4,400 rpm, enough 
> to
> propagate cracks in the crankshaft.   Thus only the engines with the
> ability to sustain operation at and above 4,400 rpm were equipped 
> with a
> harmonic balancer initially.
> Jim Davis
>
> On Sat, Mar 21, 2020 at 11:32 AM kevin nash via VirtualVairs <
> virtualvairs at corvair.org> wrote:
>
>>
>>
>>
>> Message: 4
>> Date: Sat, 21 Mar 2020 13:36:26 GMT
>> From: "Brian" <bmoneill at juno.com>
>> To: VirtualVairs at corvair.org,    fastvair at yahoogroups.com
>> Subject: <VV> Harmonic Balancer
>> Message-ID: <20200321.093626.14512.7 at webmail09.vgs.untd.com>
>> Content-Type: text/plain; charset=windows-1252
>>
>> Just to take a break from all the carburetor mystery talk, here's 
>> today's
>> question.  What are the pros and cons of installing a Harmonic 
>> Balancer on
>> a 145 ci engine?
>>
>>
>>  The only "demonstratable" advantage of installing a Harmonic 
>> Balancer on
>> a short stroke engine is if you want a crank triggered ignition, and 
>> would
>> prefer to use a Hall effect sensor. These sensor's rely on a magnet 
>> moving
>> over them to detect the crank position. A neat, clean and really 
>> solid
>> location to mount one of these sensors on a Corvair engine is the 
>> rear
>> accessory cover, essentially "hard mounting" the sensor to the 
>> engine.
>> Mounted like that, the magnets must be placed on the crank pulley, 
>> and
>> should be around .080" away from the sensor. The magnets used are 
>> long
>> enough that the only reasonable way of securely mounting them is to 
>> use the
>> H/B, and drill close fitting holes on a hole circle. There's not 
>> enough
>> metal on the stamped steel crank pulleys to do this. Some 
>> "theoretical"
>> advantages are, that it may be possible to get a slightly nicer 
>> dynamic
>> balance of the crank/flywheel and pressure plate, and crank pulley 
>> assembly
>> because some material can be taken off the HB and c
>>  ant on the solid one. Also, the HB probably has a truer running 
>> v-groove
>> that the stamped steel pulley, and because of the torsional damping 
>> may
>> slightly further reduce crank fatigue. The only reason I run the H/B 
>> on
>> mine though is because I had to for my ignition set-up, and no other 
>> reason.
>> Kevin Nash
>> 63 Turbo EFI daily driver
>> Baddest fan on the planet!!
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