Charging System and Overdrive

[LuckyFordGuy]

I need some help. I have a 1950 Ford V8 overdrive. The overdrive quit yesterday cause it wasn't charging. I had this happen 2 years ago and it was the generator. I cleaned all the grounds, put a new generator on & charged the battery. You leave it sit for half an hour and it charges the overdrive will work good and after driving for 15 minutes it stops charging and the overdrive quits. I checked all the wiring do you think it could be the solenoid or the governor?
Help would be appreciated - Rog in MN

[joe 1950]

put a voltage meter on the battery run the engine at @1000 rpm or more you should have at the least 6.8 volts or more digital meters work the best try this first sounds like your gen. is not putting out enough volts

[donald1950]

have your generator checked and check your voltage regulator.... if you do not have a shop manual, G&G Ford Parts has them and that will give you information on how to service the complete charging system........

[Paul/Woodinville]

I had the same sort of problem on my 49 while about a hundred miles from home. What I found to be the problem was that the solenoid was shorting out and causing a direct voltage draw which the generator couldn't keep up with. I pulled the fuse on the relay and the amp meter showed charge again. I had to drive home on the freeway without overdrive which was not fun especially since my wife was with me.

[Frank Miller]

Funny it did not short out enough to blow the fuse.

Originally Posted by Paul/Woodinville

I had the same sort of problem on my 49 while about a hundred miles from home. What I found to be the problem was that the solenoid was shorting out and causing a direct voltage draw which the generator couldn't keep up with. I pulled the fuse on the relay and the amp meter showed charge again. I had to drive home on the freeway without overdrive which was not fun especially since my wife was with me.

[D. Jones]

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Originally Posted by Paul/Woodinville

I had the same sort of problem on my 49 while about a hundred miles from home. What I found to be the problem was that the solenoid was shorting out and causing a direct voltage draw which the generator couldn't keep up with. I pulled the fuse on the relay and the amp meter showed charge again. I had to drive home on the freeway without overdrive which was not fun especially since my wife was with me.

Perhaps the draw in coil stayed active instead of the hold in coil, that would cause a high draw of current.

Just my $0.02 worth.

[Mike51Merc]

Originally Posted by D. Jones

Perhaps the draw in coil stayed active instead of the hold in coil, that would cause a high draw of current.

Just my $0.02 worth.

I agree. A "short" will cook the wires or blow a fuse. A heavy draw is not necessarily a short, but it seems that a lot of people use "short" to describe every possible electrical glitch.

When my OD suffered from a slight voltage drop, the solenoid would try to throw but it couldn't because of the voltage drop. The result was that it continually tried to throw, causing a heavy current draw which made the voltage drop worse. A vicious cycle that can only be cured by fixing the voltage drop.

[LuckyFordGuy]

I think I got it voltge reg or slipping fan belt thanks for help Rog

[Paul Bennett]

I believe the OD solenoid has 2 coils connected to the external electrical power. Applying voltage to the solenoid provides energy to both coils. The heavy duty primary coil is used to suck in the armature with great force. When the armature goes in for most of it's travel, an internal set of contacts opens the ground circuit to only that primary coil as it has done its duty. The magnetic force from a light duty secondary 'holding' coil is adequate to keep the armature in place until all voltage is removed.

It could happen that that internal set of contacts is not opening up, and the heavy current from the primary coil isn't removed, thus providing an unnecessary continuous drain on the battery. This can be troubleshot by removing the OD relay fuse and placing an ammeter in that circuit. I have not heard the numbers, but if a 30A fuse is used, likely the primary current is 15A (edu-guess) and the current should drop to 1-2 A after the initial several millisecond thump.

Incidentally found the circuit on the EarlyFordV8Forum and thought it better to understand some things. Most likely 12v as gauges are 2 sizes under 6v recommendations.

[rjlester]

Sorry to resurrect an old thread, but I've had my OD quit working two or three times like this in the last year or so. It seemed to be a real hard drain on the charging system. If I pulled the OD fuse, it would charge normally. If I put the fuse back in, the OD would not engage and the charge system could not quite keep up. I bet if I drove for a couple of hours it would kill the battery.

How have I fixed it? I just let the car sit overnight, and the next day it works fine, every time. It will work fine for months sometimes before the problem comes back. Seems to be only when things get hot, but the other night, the car was not driven for more than 20 minutes and it was a cool evening.

Last summer I blamed my charging system and rebuilt the generator, new regulator too. Problem still happened after that.

I'm ok with letting it sit overnight for now. Just impressed that these 70 year old parts work at all lol. I've played with the relay, cleaned the connections and the points inside. Cleaned all the other connections in the whole OD system, everything is clean, clean clean. Had the solenoid apart, all is clean and works great most of the time. New kickdown switch.

Not complaining, just hoping to help someone else out if they are having similar issues.