Bought a non-running 58 F100 with the inline 6. It has no spark. I replaced the coil, coil said no resistor needed so not sure if I should get one that does need a resistor? I dont think my truck has any resistor currently. There are two wires running to the positive side of the coil, one red and one brown. Then the negative side of the coil runs to the bottom side of the distributor. I had to rerun that wire cause it broke while I was replacing the coil. Using a test light I did verify that there is power running to the coil when the key is in the on position and the engine is cranking. The other side however did not light up...not sure if that's how it should be. I also replaced the cap, rotor, points and condenser. Any help is much appreciated.

 

The resistor in many Fords is part of the wiring harness itself, called the "pink wire" because, you guessed it - it's pink, when it leaves the ignition switch anyway.

Somewhere in the wiring harness at the firewall it gets spliced into a conventional red wire and then coninues on to the solenoid. Coils will usually specify "Use With External Resistor". You can measure across terminals to get an idea.

This ballast or resistor business is mainly to protect the points from excess current, the voltage doesn't really matter. On startup the resistor is bypassed briefly for a hotter spark. When running though, the resistor is in circuit and drops the voltage down to 6 or 8 volts, say.

What you don't want is a high resistance coil AND an external resistor both together (like in the harness), so measure if you are not completely sure. While running.

With all that out of the way, try a known good condenser. If a good one is installed many mechanics "back in the day" would leave it as they replaced the points. Try the original if you have it. Today almost all of the brand new ones for sale, usually from you know where, are defective. The people selling them have to know this, and should be flogged. The points themselves aren't much better. Motorcraft still offers good quality points and condensers afaik. Echlin and Blue Streak were good too. No idea anymore.

 

Resistor/pink wires were not used in pre 1960 fords. A 58 would use a ballast resistor and coil marked for external resistor. Like mentioned I would try replacing the condenser.

 

I'm now getting some spark but it's very weak. How can I tell if my truck has a resistor in it somewhere?

 

I've replaced the coil, cap, rotor, condensor and the points. Not sure if the points are correctly set though.

 

If the points are old and haven't been used in a while they can get a layer of skunge on them. Drag a crisp, new dollar bill through them several times to clean if nothing else.

Check for eight volts or thereabouts when key is set to "Run" but it really should be measured while running. If there is not an internal ballast in the wiring, it should be mounted on the firewall, a ceramic wirewound.

 

You are using a coil that doesn't require an external resistor and should have at least 12V going into the coil. I'f you are only getting around 8V there is a resistor in the circut, either on the fire wall or could even be on the engine and looks like this. Without knowing if your points are set correctly you are fighting an uphill battle.

 

To set the points, get the rubbing block on one of the high spots on the distributor cam. It's important to get it on the very highest point, but use any of the 6 high spots. Some people used to use a match book cover as a feelers gauge. I would guess about .018 on a 6 cylinder. If a person was used to working with points, they could eyeball the setting and get it close enough so the engine would run well.

To check if you are getting fire through the points, get the engine turned so the points are OFF of a high spot and just take something and manually open the points. If they are firing you will see a spark. Best to be in a shady place to do this. It beats cranking the engine and putting wear and tear on everything.

 

223 six cylinder point gap is .025 NOT .018. Dwell 35-38

 

The way I heard it not sure if this is strictly true, but setting the gap is just a ballpark number to get close enough for engine to start and run. Setting the dwell, is actually what counts.

 

Thats basically correct, but if you get the points set correctly the dwell usually comes out pretty much right on. Many people use to set the points by gap and never owned a dwell meter and they ran just fine..
Todays younger people probably don't even know what a dwell meter is, I don't know if you can still buy them

 

Definitely want as hot an ignition as practical. Spark should be bluish white and audibly snap or crackle in the open air. Red or yellow spark is no good.