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

[shew01]

Over the weekend, I posted several times in new threads to keep the responses related to the issue at hand for the moment. Thank you for your patience in replying to my other posts. As it turned out, this weekend has been a "crash course" in Model As than I anticipated.

Background information:

(I cannot get a rebuilt ignition cable to read 6 volts on the points. Please skip to "Here is where I'm stuck" if you are not interested in the background information.)

My 1931 Victoria is 6 volts, positive ground.

I was initially replacing a leaking radiator. While having the car apart for that, I started on other related projects, like:

- Cleaning the horn since the wiring had to be removed to get the radiator out of the car (the horn now says "ahooga" instead of just "grunting"--that's one of the big wins so far; hopefully the new radiator will not leak, but I haven't got the car back together enough to test that yet)

- Replacing the water outlet with a unit that mounts a thermostat close to the head http://vintageprecision.com/products...ing/index.html; that seemed to go fine

- Replacing the temperature gauge (which was showing discoloration at the coolant hookup and could probably fail at any time, and the temperature gauge line looked like it was weak from previous bending)

- Replacing the armored ignition cable with the one I recently purchased from Dick Crabtree that he keyed to match my door key; doing this now made sense because the previous owner installed the temperature gauge cable through the junction box along with the armored cable, meaning that I had to take apart the dash anyway to replace the temperature gauge

I originally thought I needed to remove the distributor to remove the ignition cable. (My distributor is stuck, and I ordered a puller and a head nut torque tool from Bratton's earlier today. That story is in a separate thread.) It turns out that you can disconnect the speedometer cable on the bottom of the car to get some slack in the speedometer cable line, remove the ignition switch from the dash plate, and unscrew the armored ignition cable, in place, without removing the distributor. You can install a replacement ignition cable the same way.

Here is where I'm stuck.

- This is where I am stuck at the moment. After installing the rebuilt armored ignition cable, Les Andrews, page 1-106 (i.e., the distributor installation instructions), says, "Turn ON the ignition key and check for 6 volts from the point arm to a ground point." I am NOT getting 6 volts on the points.

- The rebuilt ignition switch from Dick Crabtree seems to work correctly. I unscrewed it from the distributor and left the cable in place in the dash. With the key OFF, 6 volts do not go to the armored cable button end. With the key ON, there are 6 volts on the armored cable button end. When the armored cable is screwed into the distributor, it does not send 6 volts to the points.

- I also tested with an emergency jumper cable from Bratton's (https://www.brattons.com/emergency-i...per-cable.html). With the clip end connected to the junction box, the button end reads 6 volts when not screwed into the distributor. When I screw the emergency jumped cable into the distributor, it does not send 6 volts to the points.

I must be missing something. I'm thinking the issue is in the distributor, but I never removed it from the car. I'm not sure where to look.

All ideas are welcome.

[Bob C]

The coil is always hot on the Model A and the switch supplies the ground path from the points to the coil. You will have 6V at the movable point when the points are open and the switch on. I think you are good if I'm reading you correctly.

[Kurt in NJ]

Try unscrewing it a turn --- perhaps the lower plate contact is pushed over--- the reproduction ones are thinner metal, bend easy

[shew01]

Originally Posted by Bob C

The coil is always hot on the Model A and the switch supplies the ground path from the points to the coil. You will have 6V at the movable point when the points are open and the switch on. I think you are good if I'm reading you correctly.

I have a business card between the points at the moment. So, during my testing, the points are always open for now.


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[shew01]

Originally Posted by Kurt in NJ

Try unscrewing it a turn --- perhaps the lower plate contact is pushed over--- the reproduction ones are thinner metal, bend easy

I tried various rotations, from one turn into the distributor through fully screwed (snug) into the distributor. It doesn’t seem to make a difference.


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[shew01]

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I also tried a jumper from the junction box to the dimple in the distributor screw hole (for lack of a better phrase). That did not send 6 volts to the points that are being held open with a business card.
(The wing nuts on the junction box are both reading 6 volts.)

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[Bob C]

xxx

[Patrick L.]

There has to something that is either grounding or keeping an open in the distributor.

[Bob C]

Double post

[shew01]

Sadly, the car started and ran fine (except for the radiator leak) before this saga started.


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[shew01]

Just to make sure no foreign material is in the distributor, I took the following picture with my endoscope a moment ago. It looks clear to me.




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[1955cj5]

Here is a link to some info that may help.

http://www.fordgarage.com/pages/adistlowerplate.htm

That site also has lots of excellent Model A information.


.

[Jacksonlll]

You have an open circuit within the distributor. Take the top plate off and, with an ohm meter, find the break in the circuit. If it was a short, you would get a spark when you connect the emergency cable to something hot.

[The Master Cylinder]

Sounds to me like the wire from the lower plate is broken/disconnected from the upper plate/points. Pull the upper plate and check the wire.

OR

You have a wireless piece o' junk lower plate that is not making contact to the points.

[larrys40]

Testing is relatively easy if you have a volt ohm meter.
A little understanding first .
The popout cable does two functions :
1. It breaks (opens circuit) the hot 6 volts to the distributor when pushed in.
2. Secondly at the same time it grounds out the hot lead of the points which is part of the theftproof feature . Which is why it is called the theft proof electro lock .

It could be the popoit is having an issue and should be checked first. Remove popout from the distributor. With popout out you should have 6 volts between ground and the end of the popout. You can check this with popout in car but removed from distributor.
If no 6 volts you have an issue with the popout as long as the 6 volts is at he red lead at popout Head . If you have it then push popout switch h in, then you should not have 6vts and with an Ohm meter should have a short between he popout end and the armored cable (ground). If so it is functioning properly.

It is also very probable that when screwing in the popout to the distributor that the lower plate tang shorted to the inner housing or the lower plate to its are loose and allowed the plate to the tab to short . Screwing in the cables can sometime put enough pressure to cause those issues. When rebuilding a distributor I always use a piece of insulating rubber between the housing and lower plate tab so that it doesn’t happen even if someone screws it in too far.

I disagree about the smoke part in a post above as the coil may be charging albeit warming if if that is he case. If either of what I noted above is true you would see reduced voltage at the points .
Use a lot ohm meter and do a little light troubleshooting. I’m confident it is the popout or distributor issue I described.
Larry Shepard

[shew01]

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


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[Bob C]

Larry, correct me if I am wrong. The distributor body should be grounded and the lower plate is screwed to the distributor body and he said he jumpered from the junction box
to the lower plate which should equal some sparks.

[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..

[Bob C]

You are right Larry, I forgot the part of the lower plate the OP is
talking about is insulated from the rest of the plate, so no smoke or sparks.
I deleted my misinformation.

[Bob C]

xxx

[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!

[30 Closed Cab PU]

Yippee! Celebration time! This definitely was an issue since the upper plate fitting into the grooves of the distributor body is what provides the ground path for the points block.

Originally Posted by 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]

They guy that rebuilt my pop out ignition switch sent me a replacement. I installed it last evening, and I now get 6 volts on the moving point arm when the ignition is on (popped out) and 0 volts on the moving point are when the ignition is off (pressed in).

I’m hoping to test fire the car in the next day or so after work.


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