In theory, it's trivial. In practice, not so easy. As others have said,
first you have to come up with a power supply suitable for modern
electronics (car electrical systems are _very_ nasty places for digital
electronics), then you have to come up with a conditioning circuit that
will handle the noise, high voltage, reverse voltage, etc. that comes from
the points, then you have to be sure the output of your circuit will drive
the input of the existing circuit.
Then, you have to worry about the fact that at least some British
tachometers used a current loop arrangement, where the power supply to the
coil actually ran through the back of the tachometer.
Then you have to find somewhere to hide all this new electronics.
By the time you are done, it would have been much simpler to find the
component to change to correct the original calibration <g>
Randall
On Tuesday, July 06, 1999 10:57 AM, Arthur H. Smith
[SMTP:arthurhsmith@compuserve.com] wrote:
>
> >> TeriAnn Wakeman wrote:
> > >
> > > ...How hard would it be for a gauge shop to convert the 4
> > > cyl tach to an 8 cyl tach?<
>
> how about divide by two. the points opening and closeing sends the
pulses
> to the electric tach and since there are twice as many pulses per
> revolution divide by two.......
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