Hello All, I just got a tach so that I can see the health of the engine as it shifts gears etc. You can see it in the 'What did you buy' thread in the antiquated section of this forum. Anyhow, it is good for 4/6/8 cyl. engines but is 6v. I know I will need a step down resistor of some type-something along the lines of the gauge resistor that my 57 Ford uses. The back has wiring spots for ground, dist. and neg I believe-I don't have it in front of me while at work. Are they that hard to wire up? I am thinking that it needs a tap into the (-) side of the coil (already 6V), a 12V power source run through a 12 to 6V resistor and then a ground. Am I correct in my thinking? I will add pics when I get home of the back. Mike
Well, to me ""ground" and "negative" say a positive ground unit to me. "dist" is encouraging, since it suggests a tachometer that doesn't need a sending unit, like a lot of old units do. So far so good. You may be home if the tach has a plastic body and you can mount it so it is completely insulated and you can run positive to positive and negative to negative (after dropping the voltage). To drop the voltage, I would suggest a unit specifically designed for that purpose rather than a resistor. The are readily available from Amazon and not expensive. A metal case probably complicates the project beyond practicality. One last thing that may blow the whole project out of the water. Ten years ago, my partner and I developed a "black box" that allowed any common 12 volt tach to operate on 6 volts positive ground. One thing we ran into is that the polarity of the signal from the distributor has to match the polarity of the tach logic or most the tach's wouldn't work. When this is the case, there is no ground available for the signal and you are S.O.L. Given the small but steady demand for 6 volt positive ground tach's out there (old Fords, GMC's, and Studebakers a**** others), I feel your best bet would be to sell the existing unit and buy a suitable 12 volt unit. Do it before you destroy the logic circuits (if they're not already burned out).
I only paid $22 for it as I thought what the heck I will take a chance. I have time before I would like to install it. Thank you. Mike
If it needs a signal generator then it will go in the for sale section. If it is a + ground and doesn't need a generator it may end up in my Model A-just for laughs. This way I can tell people I tach her up at the drag strip
Technical - Wiring diagram needed for Vintage Westach Tach 6V + ground | The H.A.M.B. Someone else found one and has the same questions as me. Mike
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