Electrical Problem

[Robert/Texas]

The points and condenser came, and I installed them. The small plastic bag that the points came in was marked USA, but the points are garbage in my mind. Only a little more than half of the electrodes surfaces match and I feel that they will be short lived. I’m thinking that I ought to get a modern conversion kit to replace them if no good original style points are available. Suggestions welcome.

After this I checked to see if I would get some sparks at the points with the ignition on, using a hard, wooden pointed stick. No go, so I got my other Model A out and did the same thing and got lots of sparks.

As there is voltage (6.1 volts) at the point arm with the ignition switch on, I don’t think that it is either the switch or the wiring. Comments here are welcome too.

I get 1.6 ohm reading between the coil terminals, but I don’t know if this should be any assurance that the coil is good. Again, any help/suggestions are welcome.

Thanks much in advance, Robert

[katy]

As there is voltage (6.1 volts) at the point arm with the ignition switch on, I don’t think that it is either the switch or the wiring. Comments here are welcome too.

Your 6.1 volts is good if the points are open, switch on or off. Points closed, with the switch on, the voltage should drop to zero.

[30 Closed Cab PU]

Remove the condenser and try the sparks at the points test again - you would not be the 1st person to get a bad new condenser. Without the condenser you will get a very bright spark at the points.


Am not sure which points/plate set up you have, but points do not line up correctly on most reproduction points, and I believe correct points can not be sourced. However Brattons makes a points block that is tooled so they will align. Read the notes provided in the link.


https://www.brattons.com/machined-di...int-block.html


The primary resistance looks good. From the coil output to each wiring post should be about 7K ohms to 12 K ohms. If it is open or very high - suspect coil. Once in a while the measurement will check out OK, but the coil fails in the car under load.


With ignition on, points closed, does the points arm measure 0 Volts? If no, then you are not getting a ground on the Points Block.

[Jacksonlll]

If your point arm is hot with the key on, and no spark when closed, it is not making ground when closed. Try sparking between the hot arm and ground. You have to get a spark there. I can't believe that the point base is not grounded.

[The Master Cylinder]

Originally Posted by Robert/Texas

The points and condenser came, and I installed them. The small plastic bag that the points came in was marked USA, but the points are garbage in my mind. Only a little more than half of the electrodes surfaces match and I feel that they will be short lived.

Have you tried 'aligning' the the points and the point block? Bratton's has a really nice machined points block, IMO is better than the origial. Also clean the nice points. I have gotten some that did not make contact because of a film covering them.

[Robert/Texas]

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Thanks, katy, 30 Closed Cab PU, and JacksonIII

I checked all of your suggestions and believe that I have replaced a bad condenser with another bad one.

Resistance from the coil output from both the + and – posts registers 7.02 ohms
.
With the ignition points open and the ignition switch on, I get 5.89 volts at the point arm, but the other three scenarios yield zero volts. With the condenser removed, I get no sparks.

I really like the idea of the Bratton’s point block. I hope to order this and another condenser from them next week.

I bought both of my Model A’s back in 1989. I bought the “AR” OCPU first and some months later I bought this roadster as a “project car”. Now at age 85, this seems to be coming a project again. I have both cars parked next each other now so I can compare measurements.

Any further help will be appreciated.
Thanks again to all of you and I’ll keep you posted, hopefully next week.

Robert

[Jacksonlll]

Keep your old condensers. You will get a much smaller spark at the points when the condenser is in the circuit.

[30 Closed Cab PU]

Originally Posted by Robert/Texas

Thanks, katy, 30 Closed Cab PU, and JacksonIII

I checked all of your suggestions and believe that I have replaced a bad condenser with another bad one.

Resistance from the coil output from both the + and – posts registers 7.02 ohms
.
With the ignition points open and the ignition switch on, I get 5.89 volts at the point arm, but the other three scenarios yield zero volts. With the condenser removed, I get no sparks.

I really like the idea of the Bratton’s point block. I hope to order this and another condenser from them next week.

I bought both of my Model A’s back in 1989. I bought the “AR” OCPU first and some months later I bought this roadster as a “project car”. Now at age 85, this seems to be coming a project again. I have both cars parked next each other now so I can compare measurements.

Any further help will be appreciated.
Thanks again to all of you and I’ll keep you posted, hopefully next week.

Robert

Did you perhaps mean 7.02 K ohms instead of 7.02 ohms? If yes that would be a good reading. If actually 7.02 ohms coil secondary is bad/internally shorted. Either way maybe swap coils since you have a known good coil in the other A? You would not even have to mount it on the firewall to test.


Voltage readings on the points arm open and then closed seems OK.




Otherwise I am out of ideas

[katy]

Originally Posted by The Master Cylinder

Have you tried 'aligning' the the points and the point block? Bratton's has a really nice machined points block, IMO is better than the origial. Also clean the nice points. I have gotten some that did not make contact because of a film covering them.

I also had a mis-alignment problem w/new points so I just carefully filed the holes in the top plate to make the mounting block adjustable.

[Licensed to kill]

So, I pulled my A out for the first time in 2 years or so and could NOT get it to start. No spark. I looked a few things over and then did a search and came across this thread. I changed the coil wire as per Jacksonhill with a new 14G wire, saw nothing wrong with the old one but changed it anyway and it find right up. Not going to say I understand it but there you have it. Made up another wire and put it under the seat. Now that it's running, I will start a new thread on how to get to run properly. Thanks.

[old31]

Originally Posted by Jacksonlll

Try a new coil wire before you start taking things apart. This fooled a couple of our members last summer and they towed it in because of an old coil wire.

Curious, what would be a test that you could do to see if a high tension lead is good or bad?

[30 Closed Cab PU]

My father used to test old tractors coil wires and spark plug wires by grabbing onto the wire while it was running and feel how much it would shock him. When asked how he could tell good vs. bad he replied "experience". Did the same thing with electric fences. Old farmers, what can I say.

[History]

I've seen old mechanics do this, some of it was to show how tough I'm sure. I've only done this by accident.

I was talked into peeing on an electric fence when I was young and never got shocked. I believe it was because the shoes I wore, custom because of a partial amputation had rubber soles. I did this several times until my mom found out and told me what could happen. I guess I never did it barefoot.

I plan on getting an extra coil wire as Mr JacksonIII mentioned.

Originally Posted by 30 Closed Cab PU

My father used to test old tractors coil wires and spark plug wires by grabbing onto the wire while it was running and feel how much it would shock him. When asked how he could tell good vs. bad he replied "experience". Did the same thing with electric fences. Old farmers, what can I say.

[wmws]

Robert/Texas if you have voltage to the movable point arm but no spark past the points the juice is not getting to ground. I have heard of distributors so corroded or so much paint that they don't make a good ground path to the block. You could take a wire and ground the upper plate to the block or directly to the battery. Then take a wooden stick and open and close the points and see if you have a good spark coming out of the coil.

[Robert/Texas]

I got some parts from Bratton’s yesterday afternoon. I installed the “Machined Distributor Point Block” and the condenser last night. The points line up well now but still nothing is working.

I rechecked some of the voltages. From the junction box (both sides) to the point block, I got 6.1 volts. From the coil (plus or minus terminals), I got 5.8 volts. I got 5 .8 volts at the point arm with the ignition on.

Cranking the engine with the ignition on, I get no wiggle from the ammeter.

With the ignition on, I get no sparking when moving the point arm with a wooden stick. (I get lots of sparks when doing this to my other Model A.)

The battery is fully charged and measures 6.3 volts. It cranks the car well enough to move it around.

I just noticed that there is no power to the lights or horn. Now I’m thinking that there is something wrong with this side of the electrical system that’s causing my problem, but I can’t see how that could be.

Any further help/suggestions will be much appreciated.

Robert

[katy]

With the ignition on, I get no sparking when moving the point arm with a wooden stick. (I get lots of sparks when doing this to my other Model A.)

Try cleaning the points.

I just noticed that there is no power to the lights or horn. Now I’m thinking that there is something wrong with this side of the electrical system that’s causing my problem, but I can’t see how that could be.

Does the car have a fuse? If so, check and/or replace it.

[ryanheacox]

Just to make sure. When you found you had no lights or horn did you check to make sure you had power at both sides of the terminal box and coil? Sounding like you could have an intermittent bad connection somewhere. That is a problem on some harnesses where the terminals are crimped but not soldered.

[Robert/Texas]

My mistake.

The points are new and gapped @ .020.

I am getting power to the horn/light switch but the horn and lights don’t work. I opened the switch housing and removed the wire clips. I got 6.1 volts on the BAT clip. I believe that this plastic switch/disc has moved on the switch body as it cannot be properly assembled (spider prongs @ 6/12 o’clock position and the switch lever @ 6 o’clock). I believe that I installed this wiring with the then-available parts available in 1990.

I also hooked up a known good coil but that didn’t help although there was some corrosion on the positive terminal of the old one. Also, some of the wiring in the junction box looks a little frayed so I plan to investigate this tomorrow.

Yes, I do have 6.1 volts at both terminal box sides and both sides of the coil. I get 5.8 volts at the point arm, about the same voltage that I get in my other Model A but I don’t get sparks out of it like I do with the other car. This makes no sense to me.

Sorry for the confusion and thanks for your help.

Robert

[Jacksonlll]

Scratch a jumper between the open point arm and ground. It should spark.

[Badpuppy]

Look for a bad crimped wire connection somewhere. Wire and terminals can develop high resistance between them over time. Check between wire ends with an ohmmeter.

You can read the same voltage across megohms of resistance until you try to run current through it.