Here goes!! Why Couldn't you run a distributor equipped T on magneto with proper rectification and current limiting. After starting on battery, could you adapt the system to switch over to magneto by rectifying the AC magneto output and adding a series resistance for current limiting (similar to a John Regan magneto charger)? A basic 6v coil/distributor ignition draws anywhere from 2 to 6 amps - very broad estimate! After extensive research on this forum and other sources, the T magneto should be capable of supplying up to 200 W at 1800 rpm. I understand this may be a best case approximation depending on input and output impedance, and other very involved electrical parameters. I am aware this is an complicated calculation, hence there is little written by Ford, or others specifying magneto power output. RPM would also have to be high enough for required minimum output, but there seems to be enough headroom in the magneto, and circuitry could be modified (possible series battery) to supply adequate power until RPM increased. I am also aware of the potential damage which could result from inducing 6v into the magneto circuit! Don't ask me why I am considering attempting this, but why couldn't this be done? PLEASE BE EASY ON ME!!!
......you're a brave man Jim.........!!!
The easy route would be to use a Model T coil in conjunction with the magneto. There is a good amount of information on setting up and using a distributor in Murray Fahnestock's book "The Model T Ford Owner" using the T coil. If you can get or barrow a copy there is a lot of information in it on other stuff too.
While a T coil is made to handle the different AC voltages from the magneto and can fire at low AC volts I wouldn't think that a modern coil could handle the 0 to 30+ or so input volts even if you added a diode/bridge rectifier etc, they are made to run at steady 6/12 volts with internal/external resistor that drops the voltage to something 4 volts output after the coil warms up.
Layden, very interesting. Thank you. This is exactly what I had in mind. They appear to use one ford coil to obtain high voltage. It's possible the Bosch coil draws too much current. They may have eliminated the need for points with this setup. I wish I could see one of these.
Thank you Mark.
Welcome! Another thing to add, when using the T coil the points are set open and close in the distributor differently if the points on the coil are left to function of closed down. It would require some reading to check.
There is a way to charge a battery from the magneto. You can find it by searching the forum. A battery makes a very good voltage regulator and will keep the voltage correct for your distributor.
A Model T with a distributor ignition uses too much power to keep the battery charged by using the magneto.
There are Model T timers that look like a distributor if you are just looking to have a different appearance under the hood. If you have a functioning magneto the stock ignition system is very reliable and nearly zero maintenance up to any reasonable RPM that the engine is capable of achieving. Far superior to any distributor setup in terms of reliability.
I've run a T motor with a distributor powered off of the flywheel magneto. It worked without any modification. No need for rectification or current limiting. As I recall (this was probably 30 years ago), it is important to have the distributor somewhat sync'ed to the voltage pulses of the mag.
In The "Model T Ford Owner", by Murray Fahnestock, there is a chapter on distributors for Ford cars. One shows the Bosch distributor set up for battery use and the points closing to load the coil, ten breaking so the coil dumps to the spark plugs. The other solution is the same distributor wired to the Ford magneto and the points stay open, then close to fire the spark plugs. With a battery system, the points open to fire the plugs, with the magneto the setup is reversed and the you set the distributor point to close on the cam to fire the plugs. Check the chapter on "Modern Ignition Systems," page 289.
Joe R. Independence, Mo.
Tom, that is interesting! I would love to hear from
anyone else who has done that. The standard ignition coil would act as a transformer if driven with AC. I think you would still need points to provide an adequate spark pulse. Without the intermittent pulse to the coil primary, and without current limiting, I would think you would quickly overheat the coil. Sinking the distributor timing to the AC magneto and engine timing may be a daunting task!
Royce, my intention is simply to see if it can be done. I do have a working magneto and Ford generator. I carry a homemade magneto charging circuit as a backup, just for fun. I have been running an 009 distributor-6V for years, and don't think I could improve performance or reliability with Ford coils. Authenticity? Not so much, but the '23 came with the distributor. A good set of tuned Ford coils and timer would set me back another $350. Knowing me, I would also have to get a hcct, ecct or Strobo-Spark! I am an incessant tinkerer!!
Thanks Joseph. That's basically what I had in mind. I'll have to get that book!
I think you could use a 6v zener in series with a resistor to get your six volts. You might need a capacitor in the circuit to smooth out the ripple. I think some of the early Ford V8 engines used a 3 volt coil, that might make starting a bit easier. Sounds like a fun experiment to me, have at it!
James Bodkin, the syncing is not as difficult as you might think. The T magneto is designed to provide maximum current right when you need it. The distributor is going to "pick off" a single pulse so you are in fact running on DC.
Here is a 'scope trace that shows it.