I set the Model A on fire.................AGAIN.

[MCHinson]

Any loose connection in the electical circuit can cause the generator output to increase, possibly as high as 20 volts. This will create heat and can quickly damage the generator and/or other components in the circuit.

Do you have a copy of The Model A Ford Mechanics Handbook? This book explains very clearly the possible problems that you could have and how to fix them.

[rotorwrench]

A short to ground caused by an electrical fire making several wires bare can also make the gen overcharge. All a cut out does is open the circuit to the gen after you turn the ignition off. It keeps the gen from trying to motor. Many cut outs have been replaced with modern diodes which only allow the current to flow out of the gen and not back in. A lot of folks think the cut out has to do with voltage regulation but that all takes place with the adjustment of the third brush in the generator. No voltage regulator in an original model A circuit. The way the gen field coils are wound it can only put out so much voltage. The third brush adjusts the current output (amps). They just barely put out enough to run the lights unless you have bad grounds, then they don't put out enough to even run the lights.

Kerby

[Tom Wesenberg]

I would suspect the problem began with a loose or corroded connection at or inside the amp meter. A poor connection means high resistence and high resistence means HEAT when current is passed through it.

The poor connection at the amp meter could allow the generator to generate more than battery voltage and thus overheat itself. That is why you DON'T want to run an unregulated generator disconnected from the battery, whether it be on purpose, or by accident through a poor connection in the charging circuit.

[Bruce Lancaster]

This seems obvious to me: You have been thoroughly warned by your car that whoever wired it did a baaaad job, probably with careless tightening and careless orientation of terminals, quite possibly aggravated by bad parts. All of this, garbage parts installed by slobs, is very fresh in my mind from debugging a "hopelessly unreliable" A one of my friends bought...
I would:
Remove instrument cluster, remove terninal box, and drop out the light harness.
Lay out parts with someone local who knows A's and examine terminal box, amneter, and big terminal on lights.
Obtain via the people here ORIGINAL ONLY terminal box, light switch harness terminal (this will likely come from a junk harness) and amneter, and a set of original headlight insides, again likely junk parts from which you will salvage the metal sockets and terminals to install onto a repro set.
Replace the little dash harness when you have a good terminal box and amneter.
Get a soldering iron, spend a few minutes learning how to solder, and transfer the wires and fiber socket bottoms of a set of repro headlight sockets onto original steel socket shells, original contact tips and bakelight plug. Nothing hard there, just systematic work to get one terminal at a time into right place. Then transfer the wires from your new main headlight terminal to an original terminal...again, solder one thing at a time.
Put all your cables and wires back in, paying lots of attention to keep electrically live metal away from grounds.
Follow the diagram in the bulletins.
This wiring stuff is well diagrammed and color coded...just careful reading and care in assembly will get it al together.

[Skeezixx]

Originally Posted by MCHinson

Any loose connection in the electical circuit can cause the generator output to increase, possibly as high as 20 volts. This will create heat and can quickly damage the generator and/or other components in the circuit.

Do you have a copy of The Model A Ford Mechanics Handbook? This book explains very clearly the possible problems that you could have and how to fix them.

Yes I have all three of Les Andrews books. The first one becoming more and more smudged with greasy mit prints. I'll check out what he has to say on the subject of smoking ammeters.

The first fire was my fault. I saw that the battery cable was chafing against the frame before I got the car but with everything else I had to fix it just slipped my mind till smoke and flames came up through the floorboard singing the strings of my wingtips.

The second fire was also my negligence; I was attending a local cruise night and didn't want to drive up with only one headlight. The springs under the headlight socket were rusty and not springy anymore. The bulb made intermittent contact with them. In my attempt to make it work temporarily by pulling them forward with a snipe nosed pliers, then twisting the bulb in, they managed to touch, and o'course, I drew a crowd at a redlight.

But in this last conflagration, I was totally blameless. I was innocently standing before the open hood panel blithely admiring the engine ticking away at idle when a companion noticed a plume of smoke arising from under the windshield.

This car sat unattended and forgotten for at least 30 years. All of a sudden I come along and try to press into service systems which have been lying dormant for all that time. It wants to die in peace but I, Like Dr. Frankenstein, insist on breathing new life into it despite all it's protestations.

So, the general consensus of this august panel is that I had a loose or corroded connection of the ammeter which will be resolved when I replace it? I doubt there is any hope of rebuilding the original after the inferno even if I knew how.

And, am I to replace the ancient cutout to it's former place atop the generator after sanding the terminals to insure proper contact?

And furthermore, I am to inspect and clean every connection of all remaining electrical devices.

Is this correct?

[MCHinson]

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Please read pages 1-365 to 1-367 and and page 4-9 of the Model A Ford Mechanics Handbook. That should help you with your electical problems. As long as you fix it so that you have good clean tight connections, good wiring with no shorts or breaks, good insulation on all of the wires, and all components in good condition, you should not have any more fire problems. A fuse assembly as sold by the vendors is a good idea also. (You still should carry a fire extinguisher anyway....)

[Tom Wesenberg]

Originally Posted by Skeezixx

Yes I have all three of Les Andrews books. The first one becoming more and more smudged with greasy mit prints. I'll check out what he has to say on the subject of smoking ammeters.

The first fire was my fault. I saw that the battery cable was chafing against the frame before I got the car but with everything else I had to fix it just slipped my mind till smoke and flames came up through the floorboard singing the strings of my wingtips.

The second fire was also my negligence; I was attending a local cruise night and didn't want to drive up with only one headlight. The springs under the headlight socket were rusty and not springy anymore. The bulb made intermittent contact with them. In my attempt to make it work temporarily by pulling them forward with a snipe nosed pliers, then twisting the bulb in, they managed to touch, and o'course, I drew a crowd at a redlight.

But in this last conflagration, I was totally blameless. I was innocently standing before the open hood panel blithely admiring the engine ticking away at idle when a companion noticed a plume of smoke arising from under the windshield.

This car sat unattended and forgotten for at least 30 years. All of a sudden I come along and try to press into service systems which have been lying dormant for all that time. It wants to die in peace but I, Like Dr. Frankenstein, insist on breathing new life into it despite all it's protestations.

So, the general consensus of this august panel is that I had a loose or corroded connection of the ammeter which will be resolved when I replace it? I doubt there is any hope of rebuilding the original after the inferno even if I knew how.

And, am I to replace the ancient cutout to it's former place atop the generator after sanding the terminals to insure proper contact?

And furthermore, I am to inspect and clean every connection of all remaining electrical devices.

Is this correct?

First, save the original ammeter. It is rebuildable or at least good for parts.

Second, yes, clean every connection and make sure it's tight. I like to use grease or vaseline on the connections to keep out future corrosion.

The charging circuit consists of the generator, cutout, ammeter, and battery and a few wires (and terminal box) connecting them. This is where you need to start with making sure the connections are clean and tight.

After that you can go after the igniton circuit, which consists of the switch, battery, coil, and distributor, and the wires connecting them.

Now, with these two circuit fixed you should have a good running car electrically, but you still want to also check the horn circuit and the lighting circuit.

Unlike modern cars, with their many circuits and fuses, the Model A is very simple and has only 5 circuits:
1. charging
2. Ignition
3. Horn
4. Lights
5. Starting

[pomadum]

You've identified the problem you have shorted wiring. Sometimes that 80 year old wiring harness just needs to be replaced. I think I would do that first.

As to the shimmy - there are many causes for shimming but a couple of simple things you can get that often will solve the problem are - Mac sells a steering stabilizer bar that you can mount in about 20 minutes. There is also a Pannard bar that sometimes help

[hardtimes]

Originally Posted by Skeezixx

While parked idling in front of a friends shop demonstrating how smoothly it idled with the new Zenith 13922 carb installed just minutes before, he noticed the car filling up with smoke.
It was coming out profusely from behind the instrument panel. I quickly undid the screws and found the ammeter on fire.

I deduced that the generator cut out was at fault and removed it. I drove it home on the battery.

This is the third electrical fire I have had since getting the car in July. Once the battery cable chafed against the frame at an intersection and the cotton insulation ignited into flames, and a week ago I had a headlight socket short out and the wires melt at a redlight.

This combined with the shimmy I can't seem to eliminate enables me to provide quite a spectacle for the neighbors.

For a quick fix this week's parts order included a new cutout and ammeter but ultimately (after addressing some of the other problems) I intend to install an alternator with a voltage regulator and fuse block.

Due to the incendiary nature of the Model A Ford I recommend carrying fire extinguishers at all times.

Skeezixx,
As a model A owner, you should look into installing a master cutoff switch in your battery system. I've located mine easily, in the front of the seat riser. First thing prior to starting...flip it ON, last thing after shutting car off...flip it OFF! This prevents any undue current draw..ever! Now , the best feature, IMO, is that IF THERE IS AN EMERGENCY...flip it off!!

[john charlton]

If a 30 amp fuse is mistakenly installed in the system ( lack of reading glasses) a repro ampmeter will go up in smoke ( spectaclular) before the fuse blows. If a 20 amp fuse is installed(with reading glasses) it will not . Dont ask me how I know this. Problem narrowed down to the brake lights I think.

John in yes we did have weather today but I have forgotten what happened England.

[palmaceae]

When I first got my 29 I did not know better so after I melted my ammeter and fried a few wires I installed a fuse block and a cut off switch. I also have a fire extinguisher.

[Skeezixx]

OK.
I sanded and wire brushed all the electrical connections.
I rewired and replaced the headlight sockets (the old ones had melted plastic bases, a crappy repro).
I installed a fuse and a cutoff switch.
I replaced the ammeter with a modern version.
I now carry a fire extinguisher.

The ammeter was a big disappointment. It's cheesy looking and I don't think it works correctly. When the car is running it stays at 0. With the headlights on it reads about +12.
I thought I had it backwards so I switched the wires and it just did the same thing but in negative.

My old one was always buried in the + as long as the motor was on.
I checked the Generator and it's charging at over 7 volts.

[john charlton]

The generator was hot because its connection to the battery and other loads had failed most likely when the cutout/ampmeter finally gave up the ghost .The generator has to be connected to load . If it is not its internal voltage will go sky high and will eventually burn out.

John in on the trail of a G28T in a Claas combine dark clear evening England.

[Mike V. Florida]

[QUOTE=Skeezixx;85227]
My old one was always buried in the + as long as the motor was on.
QUOTE]

Buried in the +? I think that is wat too much for every day driving. I'm sure that that high of amperage would cook the battery.

My car runs about 6 amps during the day. Minus a few with the headlights on.

[Skeezixx]

[QUOTE=Mike V. Florida;85515]

Originally Posted by Skeezixx

My old one was always buried in the + as long as the motor was on.
QUOTE]

Buried in the +? I think that is wat too much for every day driving. I'm sure that that high of amperage would cook the battery.

My car runs about 6 amps during the day. Minus a few with the headlights on.

Maybe that's what happened to my ammeter. So whats a good point of reference?

What should it read?

[midgetracer]

A loose connection on the ammeter probably caused the fire. Resistance to current flow causes the current to be dissipated as heat and the ammeter is where the resistance must have been, so the fire started there. Perhaps the third brush is set for too much charge (or shorted) causing the generator to overcharge. I have had an ammeter get hot and traced the problem to a loose connection. With the close proximity to the fuel tank, I believe in fuses.