Bosch Magneto help

[Guest junkyardcar]

Hello everyone. I opened a thread earlyer but I can't find it so I'm posting it again. I have a Bosch ZR4 ed.19 #3582910. I understand I can use it on my 1916 DB. It works but how do I test it's output. How do I know if it's a 6 or 12 volt? I'm including some pics hope they can be opened.

Thank for everything.

[hchris]

Magnetos are self generating spark devices, they have no connection to the cars electrics other than an on/off switch so there is no issue with 6,12 or any other voltage.

Simply hook up a spark plug from the distributor cap and hand spin the magneto, you will soon know if it sparks or not.

Fitting it to the engine (assuming you have the appropriate engine drive) is the same as a normal distributor as regards timing etc.

[Guest junkyardcar]

Hchris thanks for your help. Another stuped question.

[Guest junkyardcar]

hchris, The stuped question a wanted to ask. Is there a separate charging system for the batt? If I still need a genarator/starter what is the advantage of a magnito.

Thanks again,

[JACK M]

When you hook up that spark plug be sure to ground it to the body of the mag.

[JACK M]

With a magneto you will still be able to drive it if your battery goes dead.

[TonyAus]

The quick way of testing a magneto is to remove the large cap. Below the cap you will see a bobbin-like device (the slip ring) on which the brush at the bottom of the cap rests. Hold the point of a screwdriver about 1/4" from the brass track on the slip ring with the shaft against the magneto body and give the amature a couple of quick turns. You should get a healthy spark from the slip ring to the screwdriver. There may also be sparks to the safety gap - a brass pin adjacent to the slip ring which is designed to release the spark from the armature if spark plugs are not attached.

You may get an apparently good spark from this process but nothing when the magneto is attached to the car. This may be caused by the armature insulation breaking down when the magneto is turned at greater speed. In this case, a rewind is the only fix.

Yes, the car can be run on magneto without a battery - but do not attempt to use the lights or horn - the full charging rate of the starter/generator will blow them to kingdom come (ask me how I know!)

[hchris]

As TonyAus says, yes there is a battery/starter/generator required just as in your more modern vehicles, however this electrical system has no connection to the ignition system.

A magneto is simply a spark producing generator which was in use before technology introduced the coil ignition system as we know it today.

There are pros and cons for both systems (most aircraft piston engines still use magnetos) but in the automobile field coil ignition systems became much more reliable and less complex than magnetos.

[Guest junkyardcar]

Thanks for the fast reply you have all been a great help.