Coil has constant power
 

I have a 1929 Tudor without cowl lights. I have been running this car for a couple weeks and today it wouldn't start. No spark is what I found. I have noticed that no matter if the ignition switch is off or on I have a full 6v to the coil. Did this burn my coil out which equals no sparky? What would cause constant voltage to the coil? The ignition switch bench tests good. Is it possible a wire got switched around and it has just taken this long for the coil to finally give out? The coil looks old but that doesn't mean it wasn't put on right before I bought the car. Also I noticed I have a full 6v to the generator when the car is not running. Is this right?

Re: Coil has constant power
 

Yes, the coil is always connected to the battery. It's no more of a problem for the wires IN the coil than it is for the wire ON THE WAY to the coil, as long as there is no current flow. If the ignition key/switch is good, there will be no current flow and no possible harm UNLESS there's a short, which will show up more spectacularly elsewhere, or, at the very least, a dead battery!

CHeck for loose connections in the primary ignition circuit--the connections to the ammeter or the ammeter itself are frequent culprits. Putting a jumper wire (e.g., alligator clip leads) across the two junction box wing nuts will bypass the ammeter and permit an easy test without pulling the dash panel, ASSUMING the car has original wiring setup. Another notorious actor is a "pigtail" wire in the bottom of the distributor, which tends to short out to ground after rubbing against the distributor base a million times during spark advance/retardings.

Otherwise, condensers regularly go bad and less frequently coils do too. Typically, when either of these fail you get weak spark and crappy running rather than total absence of spark. Google or Search for test procedures or try another one.

Re: Coil has constant power
 

Steve is right. Also 6V to the generator is correct on the cutout side of the generator. 6V on the generator side of the cutout would be bad and indicate that the cutout is not working.

Re: Coil has constant power
 

Turn on the ignition switch, as you slowly turn the engine over with the crank, the point side of the coil should go to ground. If its not, check points/ignition switch/etc. Easy to trace with a voltmeter.

Re: Coil has constant power
 

This car was running good the day before yesterday. It has been cutting out a bit under a load. Today I did replace the a meter with a new one because the old one was no where near calibrated as in the needle was way off of zero. I have bypassed the new ammeter and there is still no spark. I did emery cloth the points just a bit to clean them up but other than that I've done nothing today. I pull the main wire from the top of the distributor and hold it close to ground while cranking and there is no spark still yet. I'm thinking my coil just took a dump.

Re: Coil has constant power
 

DON'T start replacing parts until you find out what is wrong. Use a voltmeter and a wiring diagram and go through it step-by-step. If you start throwing parts at it you will introduce issues and it will make it much harder to troubleshoot. 6V on both side of the coil is normal. The point side of the coil goes to 0v only when points are closed and ignition switch is ON.

Re: Coil has constant power
 

I've traced voltage from the battery, to the fuse on the starter, to the coil, to the ignition switch and back. What would cause the coil to not put out? I'm rechecking the points now. Nothing has been changed but I'm gonna recheck.

Re: Coil has constant power
 

So this is what I found. The point gap is .020. The ignition side of the coil does go to ground when the points close. When the points open with the key on there is a very pronounced spark. Ideas?

Re: Coil has constant power
 

Key On, engine stopped with points open. Now short the points contacts off and on with a screwdriver while holding the coil wire 1/4" from a head nut. Do you have spark?

Re: Coil has constant power
 

No.

Re: Coil has constant power
 

I'm going to pick up a new coil and condenser today.

Re: Coil has constant power
 

I guess the reason for my initial question was why would the coil have voltage constantly. It is just a different setup than all the antique tractors I have worked on. When the ignition switch is off there is no voltage to the coil. I was always under the impression that voltage to the coil constantly would burn it out. I guess I was wrong because the way the A is laid out there is always voltage there.

Re: Coil has constant power
 

Now you're getting somewhere. With points closed, the coil should have 6 v on one side, zero on the other kids (relatively close anyway) if still no spark out of coil, then yes, bad coil. However, I would do as Tom suggested, short across open points, watch for spark.

Re: Coil has constant power
 

But on a stock A, the circuit is not completed unless the ignition key is on and the points are closed. So no current flows until then, no burnt out coil. The switch is just in the ground leg of the circuit, rather than the hot leg.

Re: Coil has constant power
 

That suggests a bad condensor.

Re: Coil has constant power
 

So I came out to the shed today. All the testing I did yesterday was in the evening and keep in mind it was 103 degrees today. No spark at all. Grounding the points, nothing from the coil. Came out to the shed this morning. It's in the upper 80s temp wise, nice morning. I was fixing to take the coil off to take it to the parts house and figured "what the heck" I'll try it one more time. Son of a gun fired right up. What gives? The only think I can think of is bad coil and/or condenser. As cheap as they both are I'm replacing them both. I have had an inkling thinking the coil was getting weak because at loads and after the car is hot it has been cutting out a bit.

Re: Coil has constant power
 

103 yesterday, not today yet.

Re: Coil has constant power
 

In your second post you said you replaced the meter because its calibration was way off. I assume you mean ammeter and it may have shown a substantial discharge because the cutout points were stuck. This would kill the battery. When it started at a later time maybe the cutout points were no longer closed. Also any time you file the points run a pice of paper between them to clear debris. The old timers found a paper matchbook cover to be ideal.

Re: Coil has constant power
 

The ammeter was showing wrong because when I was fixing the gas gauge it fell out onto the concrete floor not because there was a discharge. My battery hasn't gone dead at all.

Re: Coil has constant power
 

There is a need to get to the cause! That takes a bit of effort with a voltmeter and an ohm meter! You can also set up a little test bench with 6 volts applied on the coil, with a condenser across the connection wires and open the wires (what maybe a paper clip in the center high voltage port to one of the terminals, and when you open the wire if you can get a good solid quarter inch spark, you coil and capacitor are OK. If not, it is one or the other, Coil or capacitor. If it is not the coil or capacitor, then you need to reinstall, and start checking with a voltmeter for continuity and open circuits not getting power and ground to the coil. Good luck