Electrical: 6 volt or 12 volt? what to do? '46 M5 pickup

[tedtaylor]

I'm in a quandary. I have recently obtained an older restoration '46 M5 pickup and have worked through many issues getting it ready for the road again. Those issues being rebuilding hydraulic brakes, cleaning/sealing the fuel tank, replacing fuel sender unit, getting an ignition key made, and now for sorting out the electrical system.

The truck was restored in 2008 and has been stored in a shipping container for the last decade. It had a dead 12 volt battery hooked up with negative earth. It has a 6 volt generator, original 3-lead regulator mounted on the firewall. It has a generic starter solenoid mounted on the firewall and what appears to be a newer "rebuilt" starter motor.

So therein i am at first very confused concerning the wiring circuit, whether 12 or 6 volt. Now i hooked up a fully charged 12 volt battery and the truck started right up and runs fine, however the regulator was rhythmically clicking away and the ammeter showed a discharge. While running, i pulled the battery cable off and the truck stopped running (i thought they would continue to run off the generator)?

I could not tell externally whether the generator was 12 volt of 6 volt, so i pulled it off and bench tested to find it putting out 7 volts. So i went and bought/installed a new fully charged 6 volt battery, hooked it up with positive ground and tried to start the trunk......NOTHING, just ammeter discharge attempting turning the key. Then i switched polarity to negative ground, still nothing. So i left in place and jumped with an external 12 volt battery. Truck started right up. I removed jumpers and the truck continued to run off the 6 volt battery. Revving up the engine the ammeter appeared to "very slightly" show a charge (as opposed to an obvious discharge) however when i turned on headlights, the revving did not offset the discharge with lights on.

So my concern is thinking i would like to keep original and stick with the 6 volt setup, however i think i may have a "mixture" of 6 and 12 volt components and don't know what to do. The starter relay and starter motor only seemed to respond to the 12 volt battery, but i know for a fact that the generator is only putting out 7 volts.

My question then, should i seek out and switch/install a 12 volt generator and equip the truck with a 12 volt battery? Or what is keeping my starter solenoid and starter motor from working with the 6 volt battery hookup???

PLEASE HELP!!!!

[greyben]

It is suggested that before doing any further testing verify what you actually have.

1. Verify the starter operating voltage. If it is 12 volt it won't operate on 6 volts. If it is 6 volt it can be hazardous to the starter and ring gear to use 12 volts for numerous starts.

2. Check the engine number. If it has a '56 or later installed along with a 12 volt starter it would be necessary to change the ring gear and starter to go back to 6 volt.

3. Check headlight and TL bulbs. Have they been changed to 12 volt.

4. There is a good chance the gas gauge will be burnt out if it is original if it has operated on 12 volt for very long.

On the plus side the electrical system is pretty simple for this vehicle so go with what works for your purposes.

[RadioRoy]

It sounds like your truck is still/mostly 6 volt system. Maybe like someone tried to fix a problem by installing a 12 volt battery, or they were too ignorant to realize the truck is 6 volts. Many many people cannot grasp the concepts of electrical problems.

Here's what I would do:
Look at any newer electrical part and see if it is 6 or 12 volts.
if 12 volt parts are found, Replace them with 6 volt equivalents
figure out the original problem that could have led someone to install a 12 volt battery
Buy the official Studebaker shop manual and the parts catalog
Buy a MoTors manual that covers the year of your truck. They are full of great "how-to's" and each system is explained fully

Don't panic and start tearing everything apart. Take your time and figure out what is wrong. Most likely it is one simple thing. But if someone has been "Easter-egging" instead of actually troubleshooting, they may have created secondary and tertiary problems that mask the original problem.

[StudeRich]

One thing that is clear to me is, the Solenoid is a 12 Volt Unit with TWO small Terminals for Start (S) and Ign. (I).
The Ignition Terminal is only used on Key Start 12 Volt Systems to "Jump" the Coil up to a full 12 Volts in Start Mode and drop back to 8-10 Volts for Run. I see it is not used at this time on this Truck.

We need to know what type of Starter Switch you are using, on the Floor, On the Dash or integrated into the Ign. Switch?
The older Cars & Trucks used a Grounding Starter Switch, and Later ones a Hot (-) on a (+) Ground Type and System.

Which IS it?

It does appear that the PO only got the Starting System updated to 12 volts and NOT the Charging Circuit, the Regulator is a 6 Volt and obviously the Generator is.
Probably the Reg. has been "Burned up" with the 12 Volts (-) Ground error.
You can try Polarizing the Gen. & Reg. system before replacing though.

I would start with the Starter and Solenoid replacement, and then the Reg. to get back to 6 Volts.

Then you will know if it works.

[tedtaylor]

Greyben = the starter appears to be a 12volt starter since 6 volts won't crank, but 12 volts will crank (even with direct jumping). I believe the engine to be original '46, but i don't know anything about the ring gear if it is original or changed. does that involve pulling transmission out, bell housing, flywheel????
All the lights are 12 volt (headlights, parking lights, tail lights, brake lights). Haven't checked gas gauge yet.

RadioRoy = i bought the Parts manual, but have yet to obtain a shop manual. I have not found the MoTors manual you reference either. Are they re-produced or just original used out there?

StudeRich = my starter switch is a key/starter combo on the dash, no foot pedal. You are right that it appears the starting system (and all lights) have been changed to 12volt, but the charging system (generator and regulator) have been left alone at 6 volts.

Gents, i appreciate your feedback and comments, but this truck is never going to be competitively shown, just driven and i need a reliable driver. as such, i am not adverse to converting everything over to 12 volts, since everything but the charging system has already been changed. I guess my next step would be to find/install a 12 alternator/regulator? I will certainly keep all the old parts for the next owner if they so desire to convert back to original.

[RadioRoy]

RadioRoy = i bought the Parts manual, but have yet to obtain a shop manual. I have not found the MoTors manual you reference either. Are they re-produced or just original used out there?

You can find them used in antique book stores or eBay. here's a real good one from 1950. They usually cover 12-13 years earlier.

https://www.ebay.com/itm/1950-Motors-Truck-Tractor-Repair-Manual/183211161036?hash=item2aa83c75cc:g:sdYAAOSwToda7hQd

https://www.ebay.com/itm/Motors-Factory-Truck-Repair-Manual-First-Edition-1946-Shop-Book-D9/112640168748?hash=item1a39e0932c:g:CUcAAOSwEaBaCb3a

https://www.ebay.com/itm/Original-1949-Motors-Truck-Tractor-Repair-Manual-3rd-Edition/392026116195?hash=item5b4693d063:g:aiAAAOSwkm9azMli

https://www.ebay.com/itm/Original-Motors-Truck-Tractor-Repair-Manual-3rd-ED-First-Printing-USA-1950/142579146870?hash=item2132612076:g:SawAAOSwEEBaCcTo

https://www.ebay.com/itm/1936-38-39-40-41-42-Motors-Truck-Repair-Manual-LaFrance-Mack-Autocar-Diamond/163035970420?hash=item25f5b37b74:g:nEUAAOSwVL5a78jM

[TWChamp]

Another good book to buy is the "Motor's Flat Rate and Parts Manual" because it lists parts number for the starter, generator, voltage regulator, etc.
If you have the original Champion engine in your pickup, then it should have Autolite electrical parts. It's a good idea to polarize the generator any time parts are exchanged or worked on. Polarizing is explained in the Motor's Manual.

My most dependable cars are the ones that are left as the factory built them, with 6 volts positive ground. I bought my regulator and generator from a junk yard Studebaker, so I could get good original parts, rather than some modern cheaply built parts or something that may have a bad rebuild.

[tsenecal]

My thoughts are that you still have a 6volt starter, and the reason that it wouldn't crank on 6 volts is just that it didn't have enough power to pull in the magnet on the 12 volt solenoid. You could get a 6 volt solenoid, or just jump across the 12 volt one and see if it cranks over. It may take a little work to sort out the previous owners "repairs", but you will know what you have, and how it works when you're done. Good luck with it!

[tedtaylor]

TWChamp = well i don't have any MoTor manual yet, so could you explain how to "Polarize" the setup?

tsenecal = i used jumper cables directly on the starter and the 6volt battery didn't budge it. I did email the local rebuilder (name found on tag of the starter) and sent a picture of the starter, and the truck, and questioned whether they could identify whether it was serviced as a 6 or 12 volt system. I'll relay their response then.

[altair]

Your generator should be putting out at least 40 volts and yes it should run on the generator with a slightly increased RPM, however this practice is not recommended.

[TWChamp]

To polarize the generator you need to send battery voltage to the armature. Just use a short wire to jump the B terminal (battery) on the regulator to the A terminal (armature) for one second. Now the field poles will have the residual magnetism so the generator can send out the correct polarity voltage when it spins fast enough.

[tedtaylor]

UPDATE:
I think i'm leaning toward locating/installing a 12 volt "generator" with regulator.

To summarize, the following parts already installed appear to be 12 volt (starter, starter solenoid, all lights, new battery). The only remaining 6 volt parts are the generator and regulator. Right now, i can start the truck up, it runs good and all lights work well, however charging the battery is not effective or correct.
So after much thought and being on the fence, I've decided to explore replacing the generator and regulator with 12 volt devices.
As much as a more modern "alternator" might be better functionally, i am leaning toward keeping it original looking, so i'll put off installing a modern alternator and stick to keeping the stock appearance, but with the "upgrade" by making it 12 volt.

Can someone recommend a direct replacement exact fit 12 volt "generator"? What make/manufacturer, model, spec??

[tedtaylor]

Well not hearing back, i did my own research and just bought a refurbished/restored 12 volt generator 30 amp, fits '58-'61 Studebaker pickups. Ordering appropriate regulator and will update next week with progress made.