James S. Davis
5719 Kenwick
San Antonio -TX -78238
I don't suggest anyone making this conversion unless they feel it necessary. I'm a bit of a purist. Just the same I have seen to many jerry rigged cars and a few that I would not want to get into for fear of fire and thought this might keep a few Studes running that otherwise might be junked or burned.
If you see any errors, feel free to correct them. I tried to catch all of the loose ends, but no one is perfect.
Any questions I can answer please feel free to contact me. J. S. D.
The following are my experiences in converting a 1955 commander from 6 volts to 12 volts. The same process should apply to any pre 1956 6 volt Studebaker model.
First of all to avoid legal problems and criticism 2 point need to be made. Before beginning any work based on the information I am about to provide the accuracy and applicability should be verified with someone knowledgeable in such manners. Secondly, the 6 volt system as originally installed in pre 1956 Studebaker's was very adequate. I do not recommend altering it with out good reason. In my case I drive my Studebaker daily and on many log trips. The 12 volt system has allowed me to be able to easily locate electrical parts should they fail on the road. It has also allowed me to install a 1957 vintage after market trunk mount air conditioning unit.
For the project to be really useful it will also be necessary to change from positive to negative ground. During this discussion existing negative post or wire refers to that connection that was negative during the original configuration.
If you do not convert to negative ground modern accessories can not be used and the 1956 fan motor may run backward unless rewired. If you follow these directions when you are finished all systems will operate on 12 volts and will be negative ground.
Step 1: DISCONNECT THE BATTERY
GENERATOR: Replace with 12 volt generator as used on 1956 model, or replace with a modified alternator as is sold by the Western Lake Erie chapter of SDC or use a 10si as listed in the (alternator swap GM wiring) as listed in this data base. I would strongly suggest using the alternator if you are contemplating adding air conditioning or any other large accessories. Installation is simple, does not alter the existing wiring and is fully explained in the instructions that come with it. Replace the voltage regulator with Studebaker part from a 1956 model if you are using a Generator.
IGNITION: Here we have to replace the coil with a new 12 volt coil. Be sure when installing to reverse the wires going to it. The wire that had previously gone to the positive post of the coil now goes to the negative and the wire that previously went to the negative post of the coil now goes to the positive post.
Before hooking up the positive wire place a ballast resistor in the circuit between the positive coil post and the wire going to it. One like that which was used on early GM cars is commonly available at most parts houses. The remainder of the ignition can remain as is.
STARTER: Strange as it my seem, the standard 6 volt starter will in most cases work just fine on 12 volts. Do not run the starter too long (30 seconds at a time) however. The option is to either modify a 1956 starter motor drive gear or replace the flywheel ring gear with a 1956 ring gear to match the drive on a stock 1956 starter motor. I have tried neither. Not to worry, the 6 volt starter will not run backwards when the voltage is reversed (negative ground). Replace the starter relay with Studebaker part from a 1956 model, or use a Ford type from your local auto parts store.
OVERDRIVE: Replace dash mounted relay with Studebaker part from a 1956 model. Replace solenoids on the transmission with Studebaker parts from a 1956 model.
ELECTRICAL: Replace the wiper motor with Studebaker part from a 1956 model. Replace the Climitiser motor with Studebaker part from a 1956 model. Replace the defroster motor with Studebaker part from a 1956 model. The shaft hole in the fan will need to be drilled out slightly to accept the slightly larger shaft on the 1956 motor. Use a drill press if possible to ensure that the hole is straight and square. Replace the horns with Studebaker parts from a 1956 model. Replace all of the light bulbs, including the head lamps, turn signal lamps, parking and brake lamps, turn signal and high beam indicator lamps, dash lamps and dome lamp, with 12 volt light bulbs. Replace the horn relay with a 12 volt universal relay. Replace the turn signal flasher with a 12 volt heavy duty universal or Studebaker part from a 1956 model. It may be necessary to build jumper wires to connect it to the existing socket as the mounting pin arrangement is not identical. In some cases such as the fan motors ballast resistors could be used to drop the voltage. I do not recommend this however. There are 2 problems with ballast resistors. 1: When using a ballast resistor you require twice the power to operate the motor, causing a strain on the generator / alternator. 2: resistors produce heat that may be hazardous it improperly placed. In addition ballast resistors will not wok satisfactorily on gauges.
GAUGES: Now the fun begins. All of the gauges are designed for 6 volt operation. To hook them up to 12 volts will burn them out and possibly their sending units also. I found the easiest way to correct this problem was to build a voltage reducer, the diagram and parts for it are included at the end of this article. (Figure 1): When building the voltage reducer, drill several holes in the box to allow for ventilation and mount in an area under the dash that does not get excessively warm (i.e.., keep it away from the defroster ducts, etc.) Radio shack, at the time I built the voltage reducer, sold only a 5 volt regulator chip. They may now have a 6 volt chip. The 5 volt chip does a good job; however, for finer accuracy in the fuel gauge you might try and find a 6 volt chip. Such a 6 volt chip would carry the code number LM7806 regardless of manufacturer. The rest of the circuit would remain unchanged. Do not attempt to run anything other than 2 gauges maximum off this circuit. Any larger load will damage the circuit and possibly what it is that you are trying to power.
1: remove the existing positive lead from the back of the gauge and re-hook it to the negative post (after removing the existing negative post connections). 2: If the existing negative post was used a junction terminal be sure to secure all of the wires together and insulate. (Figure 2) Next run a wire from one of the original negative gauge leads to the voltage reducer power input post. Finally hook the voltage reducer power output leads to the existing positive posts of the gauges. (Figure 2)
BATTERY: Get yourself a 12 volt battery that will fit the tray. Hook negative to ground via the strap to the engine block. Hook positive to the starter relay.
CHECK: Immediately after hooking up the battery check for warm wires, smoke or burning, particularly around the ignition switch and starter relay. No, I'm not kidding, it doesn't hurt to be careful. Turn the ignition on and again check for warm wires, etc. This time check all of your new wiring and installations. Check fans, windshield wipers, turn signals, headlamps, brake lamps, gas gauge, etc. For proper operation. Start the car and test all systems. Check for warm wires etc.
All of the 1956 parts fit identically as did the original in my 1955 application with the exceptions that were noted in the text. My special thanks to Bill McDowell of Packard Farm who verified the interchangeability of parts before I started. JSD.
The picture above shows James' diagram for the voltage regulator for the gauges. To print it select file then print view and in page setup change the page size to 90 % and print just that page. Below is the parts list of the materials needed to build the regulator, with the item number in the list below corresponding to the large numbers on the diagrams proceeding.
5 volt regulator parts list (part numbers are for radio shack)
Item qty part description part # price ea. Total
1 2 lm7805 5 volt regulator 276-1770 1.19 2.38
2 2 0.1 mfd capacitor 272-135 .49 * .49
3 1 safety barrier strip 274-658 1.49 1.49
4 2 Fuse holder 270-739 .79 * .79
5 2 1 amp fuse (fast acting) 270-1273 .69 ** .69
6 2 heat sink 276-1363 .79 1.58
7 1 experimenters project Box 270-283 3.29 3.29
8 1 18 gauge stranded wire 278-1303 2.19 *** 2.19
* 2 per package
** 3 per package
*** 3 spools, 3 colors per package