| Ira,
BJ8 tach is electrical, no cable from the distributor drive.  So you 
would need to simulate the primary circuit through the induction coil of 
the tachometer.
Just guessing, a zero to 12 volt square wave at a frequency of something 
like:
    3000 engine rev/min   1 dizzy revolution
    ------------------- * ------------------- * 6 cylinder  = 150 Hz.
      60 sec/min          2 engine revolution
As Kees suggested - in a car would probably be easier.
Cheers,
Bob Haskell
AHCA 3000 MkI registrar
http://www.ciahc.org/registry_3000mk1.php
On 12/24/2017 06:41 PM, i erbs wrote:
> Drill motor connected to cable. Or just spin the cable with your fingers 
> to detect movement. If it spins,? could be? angle drive or bad cable.
> 
> On Dec 24, 2017 3:08 PM, "Bruce Peters" <rv9aplane at gmail.com 
> 
>     How does one go about testing a tachometer (?67 BJ8) to see if it?s
>     functional?
> 
>     Thanks and Merry Christmas!
> 
>     Bruce
> 
>     Sent from my iPad
>     _______________________________________________
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