Has anyone here installed a Tach on their T engine? If so, what did you use? Can you post or email pictures? Thanks, Dan
A suggestion - if your car has been up graded to an alternator, you may be able you use a marine or diesel application.
If you have a distributor, an impulse tach may work.
For reference see: http://faria-instruments.com/site_manuals/IS0100_Tachometers.pdf
I had to install a pair of Tachs recently on a large Drill rig. The rig had been re-powered with a Cummins KTA 600 engine with no mechanical tach drive. Bosch makes a nice Marine diesel programmable Tach with a 0-3000 RPM sweep. The trick was finding a good signal to drive the tachs, which turned out to be the raw AC test pin on the alternator. To calibrate the tach, I established the idle speed with an optical handheld tach reading the speed of the front pulley. I programmed the Bosch tach to this speed and it extrapolated the rest.
At the time I was thinking how easy it would be to do the same on a model T engine, by reading the AC off the mag. The tach would need a 12VDC reference source which could be a small battery.
I am no electronics expert, but it seems to me it would be possible to use a pulse counter on the MAG output and divide by the number of magnets for the read out. I think it has been done before.
This isn't even close to period correct,
But it's easy to install and uninstall.
Not too expensive either.
Yes the Tinytachs work however their non-replaceable internal battery is a drawback. Throw it away and buy a new one when it quits.
I don't understand how the tiny tach would work with standard model T buzz coils. How many sparks per revolution?
Most Tachs just need a train of pulses or AC wave to determine speed. The tach I referred to does it internally no need for any signal conditioning. I think it would handle 0-50VAC, which is within the the output of the Ford mag. The number of cycles per revolution was not an issue either.
I'll bet you could just hook almost any programmable tach to one of the timer wires and wala or points of course. :-)
Hello Dan: Indeed I have successfully installed a very suitable-0-2600 rpm,NOS stock mechanical Stewart Warner tachometer that I found on eBay a few years ago. Although the vintage was 1920-for this unit in a black metal case, I was able to purchase another Stewart Model 26 speedometer brass case -to match the correct speedometer on my '12 Touring. With a bit of close machining and modification to the case I was able to house the tach nicely within.The mechanical tachometers were typically driven at camshaft speed- resulting in less wear on rotating parts. I was able to design such a drive that passed right through the center of my ANCO timer, with a 90 degree angle drive, that just cleared the rotating fan blades. Suitable speedometer/tachometer cables are readily available. Although this installation functioned well, the engine speed readings were always too low- by 50%! Without checking closely, I had assumed the angle drive to be 1:1. Consequently I concluded that this tachometer needed to be driven at crankshaft speed. I proceeded with a new drive from my fan belt using another 3" pulley the same as on my crank. This time round, with no angle drive employed, but cabled direct, I am reading too fast- actually double the engine speed! Only recently did I discover when I retrieved the angle drive from my stock of parts that it is a 2:1 ratio. I am thus presently in the process of mounting the angle drive between the pick-up from the fan belt and the tachometer which will indeed give me the correct input ratio for accurate RPM readings. I have lots of photos I can send you directly by email if your interested. Sincerely, Tom Forsythe