Ignition: Distributor problem

[Bill s]

I have power to the coil, but as soon as I hook up the distributor wire to the coil shorts out. 1948 Champion Flathead.

[Jeffry Cassel]

Not sure what you mean 'shorts out' The distributor can be a mysterious thing. First, in a 6 v system (which I try to avoid) the distributor connects to the + side of the coil and the ign to the neg side. If the points are closed and you connect the coil to DC current you have a short. That's why you don't ever want to leave the switch on--if the points happen to be closed, you'll burn them up. I bet if you crank it over to where the points are open, your 'short ' will go away.

[yeroldad]

You sure the wire from the dist to the coil is good? Could be shorted to the dist housing where the wire goes through the hole, or shorting anywhere else, like insulation coming off the wire. Did you check to see if the points are opening and closing by taking the dist cap off and cranking/turning the motor over?

[Bill s]

Yes I've turned it over the points open coil, cap router all good, yes I checked the wire from the distributor to the coil all good , with my test light and the key on I have power on the positive side of the coil here's the issue when I hook up that distributor wire to the positive side of the coil I get no light from positive post on the coil when I disconnect the wire from the posiypost it will light up the test light as soon as I touch it to the distributor wire it's dead

[christophe]

Did you respect the polarity of the coil? With à 6V positive ground system, the wire coming from the distributor must be hooked to the + side of the coil.

[christophe]

If you get à spark at the points while opening them with the ignition on, everything should be OK unless the coil is overheating.

[gordr]

The ignition switch supplies -6 volts DC to the (-) terminal on the ignition coil. One job of the distributor is to supply an intermittent ground (via the points) to the (+) terminal on the ignition coil. With the distributor cap off, turn the engine by hand, or bump the starter, until you see the points open. If you still see a spark when connecting the primary wire to the coil (+) terminal, you may have a shorted condenser or a wiring fault somewhere on the primary wire. With the primary wire connected, and a test lamp between coil (+) and ground, you should see the test lamp flash each time the points open as the engine is cranked.

[Ross]

Uh, when your points are closed and you touch the positive side of the coil you will get no voltage reading. That is normal. The points are providing a ground as they are supposed to and so there is nothing left over to light your tester. It is not really a short in the usual sense of the word as the coil is acting as a resistor. Like Gordr says, your light will come back on every time the points open.

[altair]

I have had the small wire from the points to the supply ground out and break inside the insolation. This small wire is continuously flexing and can break or can chaff on the distributor housing. It is a good policy to assure the wire is free and clear of chaffing. I had this wire break inside the insolation while motoring down the road, you could not physically see the break as it was inside the insolation. I found the break by SH luck by probing in the distributor and noticed a spark inside the insolation. It would also be a good policy to replace the insolated wire with a new one at regular intervals because of the flexing action. I have also had this wire exposed because of detreated insolation. It is small but mighty. Also as mentioned above the conductor passing through the distributor housing is insolated with a very small insulator sleeve, this should be replaced at regular intervals or inspected.