Ignition switch

[Woodie1]

We have a Tudor that decided to not get us home today. I recently put in a modern upper distributor plate with the condenser on it. I'm suspecting the ignition switch is faulty but I'm wondering if anyone has used a jumper on the new upper plate. With the key on & points open, I can't get a spark from the movable arm to the upper plate. Pulling a plug connector also shows no spark when cranking. Just wondering if the new style plate can be jumpered. Thanks.

[Patrick L.]

I don't see why it can't be jumped, but, it might not help. I'm one of the few that has no problem using the modern plate as long as it isn't the wireless version. They appear to have their issues. If you jumper the upper plate to the housing do you get power to the points ? If you remove the distributor cable from the distributor housing do you have power at the end terminal ? If so, the switch isn't the problem.

[Woodie1]

I will check that shortly.

[Woodie1]

I have nothing at the end of the cable & now it blows my fuse. Looks like cable.

[Woodie1]

I did get the car to start but now the fuse blows if I try the lights. It will let the horn blow when the engine is running but I see no movement on the ammeter. It sits on zero.

[Drive Shaft Dave]

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Disconnect the light and horn wire from the cut out then try it, you most likely have socket grounded .

[larrys40]

Check your voltages from starter at the fuse and see what that is, then both terminal Box lugs, should be same voltage. If different you have a bad connection at the terminal box or ammeter. Switch off you should have same voltage st both coil terminals.

With switch on and points open you should have 6 volts at moveable point arm.
If not you have a switch issue or possible short in distributor. As was said make sure you do NOT use a wireless plate . They cause more issues than they solve. If you have a popout temwmber when the switch his pushed in the points are grounded with the cable. If it’s not a pop out you are only switching the hot lead on and off.
Of course you need to use a multimeter to check and find the issue. Should be pretty quick to pinpoint.

Larry Shepard

[Patrick L.]

Which distributor cable are you using ? Just curious. Either way, it sounds as though there is an insulation problem. Over the years the insulation can go bad allowing for a ground/short to the outside housing.

[MAG]

A internal short in the distributor cable will create a circuit that turns the coil ON continually. It will cause the coil to heat up and will prevent the engine from starting.
Should not blow a 20 amp fuse. ASSUMING the system is wired as original.