I want fit a ballast resistor on my car. I have a Lucas dizze converted to electronic. Two wires go from the dizzie to the coil, one for positive and one for negative. Do I put the resistor between the dizzie and coil or in the supply to the dizzie.

And before you ask, the reason is the alternator is tired and is ramping up the battery voltage and consequently cooking the coil. I can't afford a new new alternator but the resistor should'nt cost much

If the Alternator is putting out too much voltage your battery as well as the coil will soon be knackered... I wouldn't try to hide a problem by altering something else and a ballast resistor is old tech probably not compatible with an electronic distrubutor.

JC

Are you sure your alternator is sticking out high volts. If its above about 15/16V then its knackered, and you should get a new one.

Is your battery OK? ie showing 12/13V without the engine running, and then an increase when the engine is running.
Is there sufficient fluid in the battery, ie covering the plates (unless its a maintenance free jobby)

If the coil is cooking, ie getting very hot, then you either need a coil that does not need a ballast resistor, or get the correct ballast resistor for the coil you have. bear in mind there are different resistors for different coils.

Diagnose the problem and fix that first. As treating the symptom instead of the cause will only lead to more tears later.

ok, as ^^^ say.

alternator woltagr when running hsould not go about 14 V; if it does, then alternator is duff.

this is usually the voltage regulatr that is gone; these can be replaced for lucase type, typically a tenner.

faling that, you can get alternator from scappy - be cheaper and easier than messing with a ballast resistor.

as ^^^ , it will kill the battery given enough time as well as blowing lamp bulbs, idea if you are driving at night.

13.4 to 14.9 is the normal alternator output range --- test at 2,500 rpm without load and underload (eg switch headlamps on and off).

Also be aware that most DMM (digtial multi meters) read high if the DMM's internal battery is on the way out.

[Edited on 3/7/08 by britishtrident]