Help needed from the electrical experts

Bob/Kansas City said:
Mitch
By probing the wires I get the following:

Black wire with key on I get .3 volts. with key off I get no voltage

Red wire with key on I get .46 volts and with key off I get 6.4 volts.

I have been wondering if this switch is good or not.

Bob
Click to expand...

Remove the black wire off the switch...key on you should have 6v at both switch terminals.. If so switch is good...
 
One quick way to overcome a problem you are describing is to have a spare distributer that has been run on your car with the timing set for your car. You also should have a by-pass cable. You can make one from a discarded pop-out cable connector or you can buy one ready made.

Bratton's has them for $14.75, part number 16360. It is called an emergency Ignition jumper cable.

If you are not getting battery voltage to the ignition points, yet voltage is present to at least one side of the coil, it means there is either an open or short at the ignition key, inside the pop-out cable, at the connection to the distributor, the wire on the lower plate in the distributor, the connection to the points under the upper plate, and a possible shorted condenser. Anyone one of these could be the fault.

To quickly get the car back on the road if you are stalled alongside, replace the distributor and connect the bypass cable to it, put the clip lead on the low side of the coil where the red wire should be. remove the red wire first.

You have now by-passed all the fault possibilities described above and the car should start right up. You will have to remove the clip lead from the coil to shut the engine off.

You can drive the car indefinitely this way. However, the task is to locate the open or short. This can be done by disassembly and inspection of the distributor and checking the pop-out cable with an ohm meter.

I carry a spare distributor and by-pass cable with me and have had to use it several times along the road when a fellow club member drifted to the side of the road. The first cry that usually goes up is "change the condenser". It is much quicker and provides positive results to change the distributor and hook up the by-pass cable. You do have to re-set the timing for a different car.

Tom Endy
 
Tom Endy - Unfortunately I don't have an extra distributer so can't approach this problem that way. The dist on the car is freshly rebuilt with new top and bottom plates, new wire between the two, new points, condenser, rotor, cap, body and high tension wire to coil. I'll have to again recheck all inside the distributer to be sure there are no shorts. Thank you for your suggestions.
Bob
 
Mitch//pa said:
Yes it's good::: move on down the line as mentioned.
Click to expand...

Is there a method of checking the cable from switch to distributer to see if there is a short? To me it seems odd that with the black wire from the cable attached to the switch and with key on there is very low voltage in the black wire from the switch. Maybe a dumb question but wouldn't this be the reason why there is no juice getting to the distributer?

Bob
 
Bob/Kansas City said:
Is there a method of checking the cable from switch to distributer to see if there is a short? To me it seems odd that with the black wire from the cable attached to the switch and with key on there is very low voltage in the black wire from the switch. Maybe a dumb question but wouldn't this be the reason why there is no juice getting to the distributer?

Bob
Click to expand...

Yes you should have 6v all the way down to the point arm key on points open.

Remove the armored cable.. Key on you should get 6v at the end going into the dist... If the problem is in the dist or the cable was screwed in to far. Nothing in the circuit can touch the dist housing incld the spring contact that the cable end touches

Or

Leave the switch off then you can ohm everything for an open...
 
To easily check continuity from switch to dist., remove the ignition cable from the dist., turn on the key, and scratch the end of the cable on a head nut. If it sparks, you've got juice through the cable and to the dist. If not, you've got a bad switch or shorted cable. If juice gets that far but you don't have spark at the points, the problem is likely either a short in the dist. or you had the cable screwed in too far. That's the way us shade tree mechanics do it, anyway.
 
Bob/Kansas City said:
Is there a method of checking the cable from switch to distributer to see if there is a short? To me it seems odd that with the black wire from the cable attached to the switch and with key on there is very low voltage in the black wire from the switch. Maybe a dumb question but wouldn't this be the reason why there is no juice getting to the distributer?

Bob
Click to expand...

The low voltage at the switch contacts tells me you have current flowing through the switch, but it's shorting to ground before it reaches the points. My bet is the cable is screwed in too far, or the lower plate wire terminal is touching the spring or housing. Marco posted a good picture of how the terminal needs to be bent close to the nut. If I find that picture I can repost it.

BTW, the low voltage at the switch is because the primary winding in the coil is dropping the voltage to less than 1/2 volt, as it should. The only problem is the points aren't providing the coil ground.
 
Here is that picture of Marco's showing the correct bend in the lower wire terminal.
 

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My bet is you still have a short in the distributor or ( a lesser possibility of one in the wire leading to it). I would suggest doing as I prescribed earlier and unscrew the distributor lead into it a few turns as the lower plate may be shorting from screwed in to far. You also want to check to make sure the pigtail terminal and connection isn't shorting to the upper plate or to ground on casting otherwise.
If you need some help in KC Milt H is very good. I know him personally. I believe someone gave his number but I would prefer you PM if you need it.
I am in St. Louis and do service/restoration here on the other side of the state.

with the key switch on and points insulated and open you should have 6 volts at the moveable point arm. If not and voltage is low I believe you have a short somewhere in the distributor in one of the places I described.
Hopefully you will locate it.
Larry Shepard
 
Thank you to all for the additional suggestions. My guess at this point is that either the cable is bad or I have a short in the distributor.
I want to make sure that I have installed the wire between the two plates like the pic that Tom W posted from Marco's site.
I'll do some more testing today and report back with the results.
Thanks for your help and patience!
Bob
 
When you get the distributor back together and while it is still out of the car. Place a business card between the points and put ohm meter leads on the arm of the points and on the casting, then actuate the spark advance lever back and forth. You should see an open reading.

If you see a reading it means the lower wire connection is contacting ground.

Tom Endy
 
I have had the same problem very frustrating . I could use a screwdriver to simulate the points opening and closing and got a spark at the coil . Turned out to be a manufacturing fault with the points although visually they looked good actually the one of the pionts "button" was not connected electrically . Changed the points and problem solved .

John in Suffolk County England
 
I have been following this thread with great interest as it mirrors my own frustration at the moment - save for my system being 12V -ve ground. The information provided has been very helpful in narrowing down where I need to concentrate on solving my own issues - even though references to passenger/driver side threw me for a while as I forgot you drive on the "wrong" side of the road in the US! But the information and support has been top notch and I hope Bob gets his problem sorted ASAP.

John
 
I was surprised to see that he could get a repro cable screwed in 3 turns. Maybe they are designed differently but I've got an original and I only got it in about 1 1/2 turns. I figured all it had to do was make contact.
 
I wanted to report back with the rest of the story on the results of the testing I did last night after I got the garage warmed up. I found that the repro cable from switch to distributor was ok. After that checked out I disassembled the distributor again where I found what looked like the wire between the plates could be shorting out.
I bent the flag on the end of the wire and routed it around like the photo posted by Tom W. in post #30 ( this photo is now tacked to the bulletin board in my shop).
I'm embarrassed that I missed this because I have rebuilt several distributors without any problems. Live and learn, I guess.
Everything else looked good so I reassembled everything, retimed the engine, re gapped points and plugs, connected the battery and hit the starter. I'm glad to report that after a cranking a few turns it caught and ran ok for first start.
I wanted to be sure all the engine work was done and it would start and run ok before continuing on with assembly of the rest of the car. Now I can go forward with the rest of the project. Should have it done by spring and finally get a chance to drive it. When it's done it will have been reborn after it was left for 30 years of storage in a partially weatherproof shed.
I sincerely thank everyone that helped with suggestions and testing procedures.
Access to information and expert help like this is what makes the Ford Barn great !
Here's a pic of the car shortly after I painted it in the fall.
Bob
 

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Beautiful car ,,,glad you got er goin........

Yes an easy mistake but diagnosing helps Many learn about the system and operation..
 
Everyone should freshen up on using your Multi-Meter! With it & your trusty old test light, MOST electrical problems can be spotted QUICKLY !
Bill W.
 
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