Cannot Get Rebuilt Ignition Cable to Read 6 Volts on the Points

[shew01]

Originally Posted by larrys40

Bob, Only if points are closed.... and there shouldn’t be smoke for sure if points are open .Pigtail should be from red side of coil not junction box if you are jumpering..

As I said, I have a business card between the point contacts for testing; so, the points are always open for now. However, I’ve tested the point arm and the stationery contact, and neither show 6 volts.

For what it’s worth, I’ve been using the driver side junction box wing nut stud for my hot wire during testing. Both wing nut studs appear to be always hot. Would testing from a coil wire be any different?


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[Jacksonlll]

Check your private messages.

[tinkirk]

Sounds to me you are trying to test a hot wire from a hot wire source
Try hooking your tester to a head stud then to you your points or cable


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[Patrick L.]

Originally Posted by shew01

As I said, I have a business card between the point contacts for testing; so, the points are always open for now. However, I’ve tested the point arm and the stationery contact, and neither show 6 volts.

For what it’s worth, I’ve been using the driver side junction box wing nut stud for my hot wire during testing. Both wing nut studs appear to be always hot. Would testing from a coil wire be any different?


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I don't understand that.
Yes both those studs are hot, should be.
To check for power, one lead goes to a good ground while the other lead is poked around looking for power. Once the power is found the light will light or the meter will show it. It won't work using 2 sources of power.

[larrys40]

Originally Posted by shew01

At this point (no pun intended), the cam screw is stuck. So, I can’t get the upper plat off to check.


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If cam screw is stuck (need bigger screwdriver and rotational force) you can still troubleshoot with it in.
Make sure cable test as noted above and then use ohm meter to test for open or short between Lower plate dimple ( ignition cable dimple) and moveable point arm with points insulated. You should have continuity then but open to ground as long as you are not shifting to the distributor housing through the access hole of cable . Easy to do accidentally .
Keep us posted . Electrical troubleshooting is part of my dna but I realize it is not to everyone. Trying to make is simple yet highlight possibilities.

Bob . I hope I didn’t offend you but you shouldn’t jumper from terminal box direct to distributor. Only red side of coil which when points are closed would complete the path to ground to charge coil. When points open coil field primary collapses and secondary ( high tension) fires.
All the best !
Larry

[30 Closed Cab PU]

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Originally Posted by shew01

At this point (no pun intended), the cam screw is stuck. So, I can’t get the upper plat off to check.


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The cam screw slot is not a true flat-blade tip . Look at the screw slot and you should see that the slot is deeper in the center of the slot. One reason a lot of cam screw slots are buggered up is using a flat blade screwdirver. Find an old large flat blade screw driver and grind the tip so it fits snugly, and then grind it curved so it fits the cam screw slot.

[Ed in Maine]

I hesitate to get into this discussion because I may have missed some earlier information. First, I assume you have removed the lock nut and screw which retains the distributer to the cylinder head. When you put the cleaned distributer back into the cylinder head, I would recommend "Never Seize." Second, you say you do not get 6v at the point arm with the points open. What does it read? If it is 0v, you have a short somewhere to ground. If you have something less than 6v but greater than 0v, you have a current flow voltage drop somewhere between the coil and the distributer.

So many times I try do something on my Model A and I find myself trying to work around other problems. In your case, you can't get the distributer out of the car to do a thorough check out. I think it is time to stop and get the distributer off the engine. Just my take, Ed

[Ed in Maine]

I apologize, I do see the earlier posts and the difficulties you are having. Be careful when removing the cam screw because the corrosion which is preventing the distributer from coming off could be on the shaft and not between the distributer body and cylinder head. The best course of action is to use the puller, penetrating oil and time. Ed

[rotorwrench]

Checking for voltage on the breaker side of the coil is not important. You need voltage on the power side of the coil. The breaker side just opens and closes the circuit to give pulsating DC to make the inductor work. The voltage is dropped on the breaker side by the primary coil whether the points are open or closed when reading with a volt meter to gound. You are grounding the circuit through the volt meter if points are open. If points are closed then it's still being dropped by the primary coil resistance. In any case, this is not the side of the coil to check for voltage since there is also a capacitor connected on that side.

The breaker circuit should be isolated from the coil to check with an ohms meter for continuity. The capacitor should also be isolated (removed) during continuity checks.

[shew01]

Originally Posted by tinkirk

Sounds to me you are trying to test a hot wire from a hot wire source
Try hooking your tester to a head stud then to you your points or cable


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Here is what I’m testing. Am I testing incorrectly?

The first picture is using an engine stud as a ground, and a junction box stud as a hot wire. I get roughly 6 volts.




The second picture is using an engine stud as a ground (i.e. the same configuration as the first picture), the emergency jumper cable is screwed into the distributor and clamped to a hot stud in the junction box, and I get zero volts from the movable point arm.

[Bob C]

I think you need to get that upper plate out so you can see what's going on with the lower plate.

[shew01]

Originally Posted by Bob C

I think you need to get that upper plate out so you can see what's going on with the lower plate.

It’s still stuck. The distributor is stuck too. I’m still spraying it with penetrating lube and tapping on the metal to set up vibration.


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[shew01]

Is there a way to use an ohm meter to look for a short in the distributor while it’s stuck in the car?

This is my multimeter.




What are the test connection points? How many ohms should I expect to see between those test points?


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[30 Closed Cab PU]

Remove the ignition cable from the distributor, points open. One meter lead through the ignition /distributor opening meter lead touching only the dist/cable connect plate. The other meter lead to any connection that is on the distributor body (points block, upper plate, etc). Should be extremely high ohms, may see a little fluctuation from the condenser being in circuit.


Close the points and ohms should go to a short/very low ohms.

[larrys40]

Originally Posted by shew01

Here is what I’m testing. Am I testing incorrectly?

The first picture is using an engine stud as a ground, and a junction box stud as a hot wire. I get roughly 6 volts.




The second picture is using an engine stud as a ground (i.e. the same configuration as the first picture), the emergency jumper cable is screwed into the distributor and clamped to a hot stud in the junction box, and I get zero volts from the movable point arm.

Honestly I gave you good advice but you are not following it. Do not use the terminal box stud as hot. Use he red lead if the coil . Test as I described before . You can do his work the distributor in the at and upper plate in if you can’t get cam loose... unless you detect aprow there . Re read my tests. I was an electronic test have given many model a electrical troubleshooting seminars and tries to break it down for you .
Your voltage at the starter switch, bithcterminal box studs and both sides of coil should all be within a 10th of a a volt or two.
I think you have either a popout issue or lower plate issue.

See my notes on lower plate issue and warning .
Larry shepard

[larrys40]

Also
By the looks of your Your battery voltage your battery needs charged as it should read 6.1 or more unless you have some poor connections.

[shew01]

I think I found the issue. This is my first time removing a distributor; so, I’m definitely green at this.

I thought I had finished for the night, but curiosity got the better of me, and I started cleaning the grime off the distributor. I eventually noticed that the upper plate would not rotate within the distributor. (Apparently, I had turned the upper plate without knowing it, and it had hopped up out of a grove in the distributor.) When I pressed down on the upper plate, it slid into a groove, and it rotated again like it should, and the upper plate arm matched up with the slot in the black plastic distributor cover. I test fitted the unit in the car with the emergency jumper, and I am now getting 6 volts on the moving point arm.

Tomorrow, I plan to finish cleaning up the hardware and try final assembly.

Thanks, everyone, for your help. This has definitely been a challenge for me.


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[shew01]

Originally Posted by larrys40

Also
By the looks of your Your battery voltage your battery needs charged as it should read 6.1 or more unless you have some poor connections.

It’s a poor ground. It turns out that the particular head nut I was using had some crud on it. I get 6 volts on a firewall screw. Thanks for your help.


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[shew01]

This afternoon, I cleaned the crud off the distributor, oiled the distributor, put it back on the engine, hooked up the rebuilt ignition switch, changed out the cracked coil wire, and connected the spark plugs for a quick test fire of the engine. To my pleasant surprise, the car started on the first crank. That last sentence is what I really enjoy in this hobby. [emoji4]

Thanks, everyone, for your help. I couldn’t have gotten through this without you.

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[J Franklin]

Glad it all worked ok. Keep it up and you will become the expert that will be helping others!