No spark at plugs - 41 Dodge 6V

[miker]

I have a  completely stock 41 Dodge Business coupe (6V).  Was hard starting but ran ok, parked it and now no spark at any of the plugs.  I've cleaned the points, checked for the little wire grounding inside the distributor and changed the condensor. With ignition on and I put a screwdriver at points to 'arc' them I have a strong spark.  When i disconnect the high tension coil wire from the distributor, hold it to a ground and crank the engine i get nothing.  I'm thinking i have a bad coil (it's the original type with the wires on both ends for the armored ignition cable).   

 

Is there a simple way to make sure it's the coil, before I buy a new one? Am i missing something obvious?

 

Thanks in advance for your help.

[Plymouthy Adams]

you need to get up to speed with the ignition system and what creates the spark and trouble shoot from there....if you get a strong spark with the screwdriver arcing the points, your coil is working.....sounds like you points are not opening at all (this is when the spark is created on collapse of the field inside the coil) OR you have shorted the two contacts at the wiring connector at the points.  By your note you saying you are holding the high tension at the distributor to ground....it must not be ground but a gap so you can see the secondary voltage spark as it jumps the gap.   Again, check for short in distributor.

[LazyK]

Also check the rotor and the contact point in the distributor cap.

When was the last time the cap and rotor were replaced as a set.

Edited October 4 by LazyK

[Los_Control]

I'm coming out of left field here .... my issue is not very common.

 

I noticed with my no spark to the plugs issue, I had power going to the points and could create a spark with a screwdriver.

 

I ended up taking the distributor out and bench testing it I had a extra battery and rotating the shaft to operate the points .... the points caught on fire.

The issue was the rubber insulator pad that insulates the points plate from the body of distributor ... when you connect coil wire to the distributor.

 

The old rubber insulator was rock hard and failed. Connecting power to the points it was connecting power to the distributor body and a direct short.

The only thing that makes sense to me, with the distributor installed the engine was a huge heat sink and absorbed the electricity .... so no fire or obvious reason for no spark to plugs.

 

Once the distributor was removed and tested on the bench, the points literaly burst into flames 2" tall. It no longer had a huge heat sink to absorb the power.

To correct this you need to remove the points plate and insulate the electricity from the body of the distributor.

 

Not a huge deal, but there are a few different insulating points to look at. .... Lets not hope it is your issue .... these distributors are always easier to work on when on the bench .... same story as a bad ground wire that needs repaired inside distributor .... just a little more involved to repair.

 

Again, just a posibility when you run out of ideas.

[Merle Coggins]

The distributor body wasn’t a heat sink. What’s more likely is that when installed your power was routed through the coil, so your distributor short just created a ground for the coil circuit. When you bench tested it you likely connected the battery directly to the distributor terminal. This caused a direct short with no load to protect the circuit. Also, the fact that the points are what burnt tells me that the current was passing through terminal without shorting through the bushing. The points are supposed to ground the circuit when closed, and when they did they couldn’t handle the full current load that you applied to them. The next time you bench test a distributor put a light bulb between your power source and the connection to the distributor. This will simulate the coil being connected into the circuit. The bulb will also blink on and off as the points open and close, as a visual confirmation that all is right. 

[miker]

Thanks all. Upon closer inspection it looks like one of the small wires was shorted to the distributor housing.  Going to replace that wire and test again.