Ignition: Coil?

[ozarkman]

Well I needed a tow last night. Looks like it's the coil. It doesn't seem to ohm out right. The old coil stays use without external resistor. The new one says use with external resistor. Now I'm scared to start the car! I don't recall ever seeing an external resistor anywhere in the engine compartment. Is there a resistor wire in the harness? Do I need to install a resistor? We have a '57 Hawk harness from SI installed.

[StudeRich]

If that is a '56 Power Hawk V8, it is mounted on the Firewall pinch weld Lip just to the passenger side of center, a white ceramic rectangular Block.

A correct reproduction '57 Hawk Harness made by Studebakers West as sold by S.I. , would not have a Pink Resister wire.

However Coils are not usually a high failure rate Part, the problem is usually in the Dist.
Further testing is required.

Pull the Dist. Cap and check for a rotating Rotor while cranking the Engine, you may have a stripped Timing Gear.

[ozarkman]

It's the Flight Hawk with the flat 6. Distributor does rotate and points open and close. Seeing 12v on both + and - on the coil wire studs. No spark at the points.

[TWChamp]

You could also have a condenser that failed. Is the resistor block before the 12 volts goes to the coil, or is it between the coil and points? I would assume it's before the 12 volts reaches the coil, like most cars, but if someone messes with the wiring you may have something different. Anyway if the points are closed and the key is on the resistor should drop about half the voltage, so you should show about 6 volts on one coil primary, and zero volts on the coil primary terminal that leads to the points. If the points are open (or have dirty contacts), then you should show the full 12 volts on both coil terminals. Remember, resistors only drop the voltage when current is flowing through them.

Most 6 volt coils have about 1 1/2 ohms, so with the engine stopped, key on, and points closed, they would draw about 4 amps on a 6 volt battery. A 12 volt coil with no external resistor should have about 3 ohms, so it would also draw about 4 amps with the points closed, and key on. A 12 volt coil that uses an external resistor would have about 1 1/2 ohms and the resistor would also have about 1 1/2 ohms.

[Bud]

It sounds like the condenser has failed causing your no spark condition. The 12 volt coil used on the 6 cylinder engines has an internal resistor and does not need an external ballast resistor. If you install a coil that requires an external resistor, then one will have to be installed and an extra wire from the I terminal on the starter solenoid will have to be connected to the positive side of the coil to bypass the external resistor when starting the engine. Bud

[acolds]

In a regards to this I was looking at my parts book and my 57 clipper(6484685) lists a different resistor than other model (439553). Also see that the coil on sedans different than C K could the coil be different because of different location? The resistor looks the same as the one on my brothers 1956 President Classic. Guess I should quit looking at the parts manual

[rstrasser]

If as you say you are measuring 12 volts on both the + and - terminals of the coil to the negative terminal on the battery with the points closed. Then there is a open in the wire between the - terminal on the coil and the points. You should read 12 volts on both terminals with the points open.
If the condenser shorts; then there would not be 12 volts on the _ terminal with the points open
If the condenser fails open then there would be a very weak to no spark out of the secondary terminal of the coil.

Ron

[studebakerkid]

some of you guys are scary...a ballist resistor between the points and ignition coil oh my..........

[TWChamp]

some of you guys are scary...a ballist resistor between the points and ignition coil oh my..........

I've seen it happen and all kinds of messed up wiring over the years. It's too bad everyone doesn't learn at least basic automotive wiring of older cars, but there are some people that can't even use a test light. A couple people have said they find the multimeter too hard to understand and read the scale. Well, for those people the answer is to buy a simple 1-15 VDC volt meter. They can be found on ebay for under $6 delivered. You just have to add two wires and clip leads.

[jclary]

I've seen it happen and all kinds of messed up wiring over the years. It's too bad everyone doesn't learn at least basic automotive wiring of older cars, but there are some people that can't even use a test light. A couple people have said they find the multimeter too hard to understand and read the scale. Well, for those people the answer is to buy a simple 1-15 VDC volt meter. They can be found on ebay for under $6 delivered. You just have to add two wires and clip leads.

Well...I've often used the expression, "I know enough to get myself into trouble. Just not enough to know how to get out of trouble!"

A simple (for me it has to be simple) way to check coils is to get one of those cheap inline spark test devices. It looks like some type of goofy bulb with spark plug connections on each end.


You can stick one end in the high voltage discharge of the coil, the other to ground. Then, power up the coil +/- contacts with jumper wires. Every time you touch the small primary (or is it secondary) wire to ground and release...you should get a big spark in that tester bulb. If the coil fires a good, healthy, bright spark...it is OK. Then you can look elsewhere for the problem, like condenser, or shorted points, etc.

I use a VOM. But, being old fashioned and numbers challenged...I use analog. I understand the motion of a moving needle better than the number values. I probably use it more for continuity checks than any other reason.

One other thing...it is my understanding that there are "Internal resistor" coils, and "External resistor" coils. If you don't see a resistor, you probably have the internal type.

[StudegaryB]

Lack of spark when cranking the engine with the starter can also be a failed starter solonoid/switch. Along with the ballast resister on the firewall there is a circuit from the starter solonoid/switch which jumps the voltage to the coil while cranking the engine. The starter solonoid switch has two terminals on it for small wires, one marked "S" and the other marked "I". The "S" terminal when it has 12V applied to it engages the starter, at that time it should also output 12V to the "I" terminal, which bypasses the ballast resister and sends 12V direct to the coil terminal. I've had instances of that starter solonoid/switch failing to output the 12V to the coil thus having no spark while cranking. Easy to get and replace since Ford and some other cars use the same switch.