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Stutz in the UK

Magneto and coil question 1917 cars

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Dear All, does anyone know please what Magneto was original equipment on my car (1917 Roadster with Wisconsin engine)

I am informed it should be a BOSCH ZR4 twin, my car has a BOSCH ZR4 Dual. so, I have a dual ignition system (one set of plugs) and a BOSCH Trembler coil, with a rotary switch on the dash board to switch it from one to the other.

The serial number of my Magneto is 1390819 and its stamped marked NEW YORK, I am told this magneto may date from March 1912?

The coil on my car has number 122838 stamped on the switch face, along with 4 volts. I have been told this dates from 1910/11?

I am informed the correct serial number for the magneto I need to find would be from the range 1900000 to 2300000

This information can come to me from a long term magneto expert in Italy, but he suggested I check with the club and other experts before looking to source a replacement. Did Stutz use 4 volt coils or 6 volt please?

Thank you in advance for any replies.

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1917 sales catalog for roadster says " Bosch waterproof". I would take that to be model ZR. The parts catalog for touring, Bulldog and roadster shows " Bosch magneto-single". That would be one set of spark plugs. The original examples I am familiar with all have a set of priming cups in the valve plugs on one side of the engine and spark plugs ( 1 per cylinder) on the other.

To the best of my knowledge no Stutz cars of any year came with the Bosch dual system to start on battery. The examples we see today are most likely owner additions to ease starting with such a slow turning starter ( or hand crank).

Those Bosch magnetos that fire 2 spark plugs per cylinder are called and labeled 2 spark. Twin at this time period referred to something else.

This list is supposed to be from Robert Bosch Germany records:


I do not know if this is calendar year or model year. I have not seen a list for later years.

4 or 6 volt dual coil, all American Bosch seem to be 6 volt. I believe the 4 volt are all Robert Bosch ( Germany). I don't know if certain countries or car makes favored 4 or 6 volts but Robert Bosch made both.

I have never seen a serial number list for the dual coils.

It can be difficult to impossible to tell where some magnetos or dual coils were manufactured as they are all metric and built to the same dimensions. Not all are marked as to place of manufacture. Some of the Robert Bosch items do have a big clue on the front. Some are marked in British English as opposed to American English, some in German and some in French.

post-34894-143142433342_thumb.jpgThis switch is marked in German ANLASS over the 1 and French FABRIQUE A STUTTGART on the flange.

Hope all this answers more questions than it raises!

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This dual coil is much like yours, 4 volts and marked with what I call British English, on the flange mine is marked M for magneto and B for battery, I can see yours is M for magneto and A for accumulator ( a rose by any other name). Mine is marked GERMANY on the back side of the mounting flange.

Most American Bosch dual coils have a face like this one:


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