This is a nice brass cased beveled glass unit that I would like to run but have no idea what the engine side hookup looks like. Any input as to how to go about getting this thing working on a T would be most appreciated.
Where could you possibly hook it up? Some weird timer cover & drive comes to mind, after that I'm blank.
Easiest would be to run it off the back of the generator like some english cars did. I don't know the tooth count so you might have to hide a ratio box somewhere.
Cool Tach. Try using an idler wheel against the fan belt near the crank pulley. John
The first thing you need to do is determine what the actual rpm speed to unit rpm measurement speed ratio is. Find or make up a connector to fit into the unit and run from an electric drill. Start with a variable speed drill at low speed to make certain the gauge isn't a low rpm unit internally (and determine direction). Do not take the gauge up over about 20 (2000rpm reading).
slowly take the variable speed drill up to determine roughly how high the input can be. If, and only if, the gauge can take the full speed of the drill without turning the gauge needle too high. Then you may hook it up to a fixed speed drill (usually about 1500rpm). Under light load, it will run very close to that fixed speed. A little math should then be able to tell you what the actual input speed ratio is.
If the unit will not run safely at the full speed of the drill, you will need to find a lower speed fixed speed to determine the input to reading ratio. Many drill presses have fixed speeds that may be low enough. I think my cheapo has a speed chart.
Another good possibility for you, is I have an old planetary gear tapping head that I run in a drill press. It could be used on a standard hand drill and has a fixed speed reduction (more math) as well as direction reversal. I could get it to you and probably give you a hand with it.
Once you have determined the direction and ratio of the input to reading display, then with a little math, you can determine the gear ratios and location to mount the take-off from the motor. The most likely points are generator, timer/distributor, or water pump/fan belt. Some water pumps could be easily gutted to run the car on thermal-siphon and provide a perfect fan-belt mount. A fan-belt mount is of course not a hundred percent accurate, if that matters.
Once all that is figured. Figuring a drive/takeoff should not be too difficult. You could probably incorporate parts of a broken-beyond-repair speedometer and cable/housing.
I remember when a good friend of mine found a tachometer at a swap meet about forty years ago. Almost nobody even knew such things existed that early. It is on his car to this day.
Great item! Thank you, Jay, for sharing with us! Let me know if I can help.
Drive carefully, and enjoy, W2
Jay, If you figure out a place from which to drive it, and need a cable, check with an older established heavy duty truck parts store. Our local truck parts store has the inner cable, outer housing, cable ends, angle drives, transmissions and the change gears to calibrate speedometers. Their supply is pretty well picked over and they are not replenishing the stock; there isn't much call for the mechanical drives since everything became electronic some years ago. I'm sure the stuff is still out there, but it's getting harder to find.
BTW early Corvette tachs were driven off the back of the generator.