ballast resistor wire

[tjk]

Hi

Can anyone tell me why I'm getting 12 volts at the coil end of my ballast resistor wire. The wire is the right colour code i.e pink white. the second wire from the starter shows 12 volts only when cranking as it should. This may be why my 6 volts coils are breaking down. Any ideas would be very helpful.

Tim

[marshman]

How are you measuring the 12v? If you have disconnected the wire from the coil then it will measure 12V. It needs a current to flow through the resistance of the wire to "drop" the voltage. Here I am assuming you have the later MK2 where the resistance is in the wire in the loom. Also even if the wire is connected to the coil unless current is flowing it will still measure 12V. If you have conventional points then you simply have to rotate the engine until the points close, then measure the voltage on the wire. If you have electronic ignition then I would disconnect the -ve side of the coil and temporarily run a earth wire to it to complete the circuit. Don't leave current flowing through the coil for too long as it will get hot and probably be damaged.

Roger

[tjk]

Hi Roger
Did as you suggested and 6 volts was registered. Yes I now see the light. Many thanks for your quick and will explained answer.
Tim

[marshman]

Hi Tim,
Pleased to help.
What are the symptoms/problems with your coils? I assume its not a heat problem caused by them being mounted too low and touching the top of the block?

Roger