I recently purchased a 55 F100 with V8. I'm having difficulty getting spark. It's a 6 volt system. I've been troubleshooting and need some direction cause things ain't working out.
Here's what I know.
The truck turns over
The 6 volt battery is new and reads 6.3 volts accross the terminals
The negative terminal goes to the block and the positive goes to the solenoid
I get 6.3 volts on a meter when I check the "+" on the coil. I also get 6.3 at the end of the coil wire that goes to the cap.
I get a spark when I touch a screwdriver to the distributor and points

Question:
To check the plugs and the coil I tried sticking a spark plug in the end of the coil to cap wire and touching it to the manifold (or any ground I could find). I thought this would give me a spark but it doesn't??
Are 6 volts different? what am I missing here.

Any guidance appreciated
Tks

 

Of course, you cleaned the test ground spot to get through any surface rust.
Did you test for spark at the plug end of any one of the plug wires?
AL.

 

No, The six volt system is the same in every way as a 12v system.

Rotate the engine until the points are open, using a screwdriver, touch the arm to ground, it should create a spark when you remove the jumper, if so, good.

rotate the engine until the points are closed, using a fingernail or some other NON conducting tool, manually open and close the points, it should create a spark when you open the points, if so, it should run, if not, replace the point set.

hope this helps.

 

He could have a bad capacitor also.

 

Have you checked to see if the shaft in the distributor is turning? If it is, I would replace the points and the condensor (capacitor).

 

Interesting. My 53 f100 was positive ground 6 volt.

 

Tks for the repsonses, to answer a few of the questions:
1 -Yes the grounding area was clear of rust
2 - Yes I checked for spark at the end of the spark plug wire - there was none at that time
3 - I did what FSC suggested as well last night and got spark at the points
4 - Yes the distributor shaft is turning

I didn't get a chance to work on the truck tonight but did some research and found the following.
- Apparently as Franklin2 suggested this 1955 is supposed to be a 6 volt positive ground system. Ford changed over in 1956. If true problem #1 is I had the battery connected backwards. Do I have a 6 volt positive ground system and how can I check. The books tell me I do.
- I didn;t mention last night that I changed the coil. The old coil for some reason would only read 5.1 volts when connected. I thought this was the problem and changed it out. I never checked for spark at the end of the wires after that. I got hung up on the thought that I should get spark by sticking a plug in the main coil wire itself and touching it to ground. I found out today that this will never work. In order to test the coil this way you need to touch the spark plug to ground, keep it there and break the positive to coil circuit. So instead of tapping the spark plug, tap the wire on and off of the coil lead and watch the spark plug for spark. In essence your copying what the points are doing. I haven;t tried this yet but will put the theory to test tomorrow night.
- Next I asked a guy at work why then did I still have spark at the points when I tested as FSC suggested. If the coil was faulty which we now suspect it will allow current to pass to the points but possibly will not sufficiently supply power to induce the coil and provide the big volts to spark to the plugs.

This is what I have learned so far. I don't know if it's right or wrong but will update if it works. Feel free to add your 2 cents.
And Oh ya connect the battery properly

later

 

What kind of coil are you using? I am wondering how the coil is wired internally. The one I had hooked the positive to the dist, and the negative to the keyswitch.

The thing is, you have two coils inside a coil. You have the primary coil that gets the 6 or 12 volts. Each end of this coil is hooked to the two small terminals.

Then you have the high voltage secondary coil. One end of this coil is hooked to the center port where the sparkplug wire goes to the distributor. But whats interesting is the the other side of this secondary coil is hooked internally to the small terminal that goes to the points to complete the circuit.

I am not sure, but I am thinking on a normal negative ground coil, the - terminal is the common for both coils. I wonder if a positive ground coil is hooked with the + as the common for both coils.

I am a little confused how it might work out, but I am thinking if you have a more modern coil, you may need to try the wires both ways to see what works for your set-up. Hook the keyswitch lead to the positive of the coil, and the dist to the negative, and if that doesn't work, swap them.