Hey guys. Just trying to get my 55 F-250 started and running some before disassembly and restoration. So, it's a 239 y block with points ignition. I feel like I have everything hooked up correctly, but I must be overlooking something. I have no spark coming out of coil. Would someone please check this hook up and advise me what I've overlooked. First of all, I have a new battery. The wiring is as follows: On coil +, I have wire going to Batt terminal of ignition switch, and I have verified current to the coil with a test light. On coil -, I have primary wire going to distributor, and I have verified current to the points with a test light. I have new points, correctly gapped at .016. New condenser and rotor. New plugs , correctly gapped, and new plug wires. Engine rotates perfectly and I have a new fuel pump-- plenty of fuel is getting to carb. I've held a plug wire and even the coil wire close to the block (using a block of wood as insulator) to check if spark is present, and there is none. I have used 2 different coils, and still end up with the same "no spark" result. I really would be surprised if both coils are bad. Any suggestions?? Thanks, David

 

Are you running the original 6 volt positive ground, or are you converted to 12 volts negative ground?

 

My plan is to do the conversion to 12 volts completely. But for now, the only wiring I have installed is this ignition component and I do have that set up as negative ground. Do you think the coil hook ups should be reversed? Thanks.

 

run a wire directly from the battery to the coil plus side see if that helps. will eliminate all the truck wiring

 

I guess I can try that, but the only other wiring is for the ignition circuit. : starter,solenoid,alternator,start button. But could it be as simple as switching the primary wire from neg of coil to the pos? I feel like the problem has to do with 6 volt pos ground vs 12 volt neg ground.

 

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We used to call that “hot wiring” a car.

 

6V+ground has the + coil terminal going to the distributor, the - to power. While it's supposed to still work reversed, just not as good, I'd certainly start with reversing those wires if they're wrong. Make sure your coil is also a 6V coil.

 

So I direct wired the battery to coil + and still no spark out of coil. I have 12.4 volts going to coil +. Could I have a short in the primary wire? Also, I will recheck point gap. Any other suggestions? David

 

I take it you are using a volt meter? what type analog or ?
I would use a old school test light for this.

You said you have power, 12 volts (test light on) as you are using a 12 volt battery, to the + side of coil, 12 volt coil?
Then you said you had power, 12 volts? (test light on?) on the coil - side with points open or closed?
If open turn the motor till the points close what happen to volts / test light on the coil - side?

If you crank the motor and test light on the coil - side it should blink and this blinking is what makes the coil charge and discharge / spark.
Meter dose not really work to good for the above test and why I use a light.
If the light dose not blink when cranking the motor when hooked to the coil - side the points are not grounded.
Some dist. have a ground wire from the breaker plate to the dist. body to ground it.
This wire has to flex easily as the plate moves to advance timing.

Also make sure the points contacts are clean. Any oil / grease / etc.can stop the points from grounding.
From sitting I have see funk build upon them and no spark.
Dave ----

 

When doing the "blinking test light" test, one probe to -coil, and the other probe goes where exactly? Stationary point, fixed point, or does it matter? Thanks, David

 

Dave has you on the right track. His suggestion about using a test light flashing is a good one. Myself, I would first double check your power wiring to your coil. Using your test light, with a test lead connected to a good battery ground, and the ignition switch in the On position, do you get power to the battery or ignition switch side of your coil?
If Yes, now disconnect the distributor primary wire to the coil, and then take one lead of your test light and connect it to the lead you just disconnected and the other lead or probe connects again to the battery or ignition switch side of your coil. With the ignition switch on, Is the test light on? If so Good, you just verified you have a ground connection inside your distributor. If not, let's see if the test light "flashes" indicating the points are installed and working correctly. With the transmission in Neutral, wheels chocked, e-brake on, have someone, turn on the ignition switch, press the starter button to turn over the engine. Your test light should be flashing as the engine spins. If it doesn't your missing a ground connection to the breaker plate inside the distributor. There is usually a little ground strap that attaches to one of the mounting bolts on the points set. If it doesn't flash, but stays on all the time, double check your points wiring. Sometimes folks connect that little ground strap to the points' insulated armature terminal, (same place the condenser is conncted) and then connect the primary wire to the points base. If that is the case swap those two connections and re-test. If those check out, and your test light stays on all the time, then make sure that your primary wire connections are not shorting out while running through the insulated stud connector on the distributor body. Sometimes the nylon/plastic bushings are broken or missing altogether. Sorry this is so long. We just need to take a step by step approach to isolate things. Sorting out what is good leading us to what is bad.

 

Thanks for the info hooler1! So I verified power to coil+ per your suggestion. For part 2, I disconnected primary wire from coil-, hooked a test light lead to that wire and the other lead to coil+, and light did not come on with ign switch on. So apparently, I do not have a good ground inside distributor. It's a puzzler because the ground strap is present and is attached via one of the hold down screws for the points and I carefully traced the primary wire for any breaks or exposed wire and it looks good. When someone is available to crank motor, I will check for blinking light but do I leave the primary wire disconnected and the test leads connected like it is (( one lead to the primary wire and other to coil+ when doing blinking light test?

 

Your points are probably open and on the high point on the cam but, yes.... Primary wire disconnected from the coil, with the test light connected to it, and the + terminal of your coil. If you don't want to wait you could put a socket on the end of your crankshaft damper bolt, and turn the engine over manually. That should give you a flashing test light too.
If you do see flashes, then it could be a bad coil wire or coil itself.

 

Hooler1, so there is a happy ending. When I did the blinking test light test, it would not blink. That is what I would expect if the points were open (like you said). However, the light would not blink when they were seemingly closed either (off the high point of the cam). I barely touched the movable point when they visually looked closed, and the light came on. So I changed the point gap from .016 to .015, thinking that was still within the acceptable range. BAM! Truck started in a split second. I guess that thousandth of an inch was just enough to keep the points from contacting to complete the circuit. Anyways, it's all good now. Thanks so much for your help! David

 

That's Great to hear David! This is a great and fun hobby especially when you fix something to help you enjoy your truck. Thanks for letting us know what you found!
Stuart