Change over to 12 volt.

Hi, Guys;

My first post this far down the page! I have a '50 Special I am contemplating adding AC to. It is a driver. SO 12 volt required. My question, to some of you who have done this, is there a "check list" to follow to be sure I don't miss any thing??

Thanks

Ben

If you want to look "correct", I would suggest a Powermaster PowerGen unit. This is an alternator in a package that looks like the original generator. The other advantage is that it bolts up to your existing engine brackets. Of course you'll need to change all bulbs. Instruments also need to be either changed or you need a voltage reducer for the instruments. These are readily available from (others shield your eyes) street rod vendors. :eek:

I assume you have vacuum wipers, otherwise you'll need a 12v wiper motor also. The 6V starter motor will work fine on 12V.

Brings up a question... Is a 6v a/c unit available? Or can one use a 12v unit on 6v? The a/c clutch is my main concern... Because the fan would probably work on high speed... Thanks!!!

hi mrspeedyt, pontiac had six volt a/c in 1954, nash too, both of these are built in dash set up's, i'm changing my 53 pontiac chieftain custom catalina to 12 volts, installing the 54 pontiac a/c system- changed it's blower motor to a 12 volt a/c blower motor, and also installing a 1955 buick factory rear a/c system that's already 12 volts, thank you joe padavano, for the info about the powermaster, that will insure me that my charging system will be more than able to keep all three a/c blowers going, plus the power antenna, six way power seat, power windows, dual spotlights, foglights, autronic eye, charles coker, 1953 pontiac tech advisor.

Joe, thanks.

The temp and oil pressure gauges are direct reading, so should be ok. I think. The amp gauge is just a chargeing indicator. Ok?? Fuel gauge, will voltage affect it??

Thanks

Ben

I used a ballast resistor from a 69 plymouth wired inline to the hot terminal on a 6V 37 Plymouth fuel gauge 10 years ago. Still works.

a

Joe, thanks.

The temp and oil pressure gauges are direct reading, so should be ok. I think. The amp gauge is just a chargeing indicator. Ok?? Fuel gauge, will voltage affect it??

Thanks

Ben

Ben

No specific answer...was hoping someone with direct experience would post.

Anyhow, this is where you have to try it to see if it works. The way I understand it is the fuel gauge is just an ohmmeter and some are affected by voltage. If it does not work correctly you can use a 'constant voltage regulator' from a Ford after 1956 into the early '60's---that's what I used on my '51 F-1 with nailhead for all of the gauges. Also if you want to use the original 6v radio I have an easy solution for you.

Willie

Willie, I will contact you later. Thanks for the offer.

Ben

Well, I bit the bullet and changed to 12 volt. One wire alt. Changed all bulbs. Resistors where needed. Push button in place of carb vacuum switch. Lights work. Horn works[ LOUD]. Hooked the alt output wire to the amp gauge input wire. And once again, I have discovered I don't know as much as I thought I did. No starter action. Probably something simple, but must have missed something. Any ideas appreciated.

Thanks

Ben

The starter solenoid and hence the starter is activated by the starter relay, a small relay in a black metal cover that looks similar to a horn relay and usually mounted on the firewall passenger side. However, they may have mounted with the starter solenoid in the 1950 models. In any case, the relay coil had one side grounded, as you would expect. The other side of the relay coil got +6 volts from the accelerator starter switch on the carburetor. When the accelrator was depressed, the relay coil pulled two contacts together sending +6 volts to the starter solenoid therby actuating the starter motor. There were two safety systems engineered by Buick to prevent the starter from actuating when the accelerator was depressed with the engine running. One was the accelerator starter switch was rigged with a ball that lifted under engine vacuum to prevent the contacts from closing as long as there was vacuum provided by the running engine. the other safety was to ground the relay coil to ground in a very innovative way. Instead of going directly to ground, the coil was connected to the armature terminal of the voltage regulator. When the engine is not running, the armature of the generator is at ground potential so the starter will actuate. However, once the engine starts, the generator armature is at + 6 to 7 volts and therfore the relay coil cannot pull the contacts together. Once you installed the alternator and removed the generator, the ground for the starter relay also went away. The easiest fix is to find the small diameter wire originally connected to the ARM terminal of the voltage regulator and ground it. This will work for a while until the starter relay, designed for 6 volts, dies under continual use at 12 volts. If you plan to use a push button to start the engine, get a heavy durty switch and wire it from the battery +12 volts with the other side of the switch to the starter solenoid. This way you bypass all the safety systems but just be careful to not push the starter button while the engine is running.

I explained this system in a Buick Bugle article about a year of two ago.

Joe, BCA 33493

Joe, I thank you. I am in Texas this weekend, so can not check, but bet I did not ground that wire. Will check first thing Mon morning.

Ben

You get the GOLD STAR, Joe. I though I had grounded it, but had missed. Works fine now.

Thanks

Ben

I noticed a couple of nice things going to 12 volt. If you double voltage, you cut current in half so all your 6 volt wiring is oversized- a good thing. The second thing I noticed was that the starters don't seem to mind it. So your generator/alternator is about the only real issue. On the generator, you must have a 12 volt regulator and an alternator makes that easy if you go that route. You will burn out all your 6 volt bulbs but they will shine brightly until they do. The other issue was I had a negative ground. To my amazement, the starter would only spin the correct direction and did not mind going to a positive ground. The radio was about the only issue, don't hit a 6 volt with 12 volts. But if you go to 12 volts, you are probably going to hide a better stereo in the car anyhow. Unless you are a real purist, there is no real need to stay with 6 volts.

The other issue was I had a negative ground. To my amazement, the starter would only spin the correct direction and did not mind going to a positive ground.

What project does this apply to? I though 12v was all neg ground. Old fords and others had 6v pos ground. The old 6v radio is easy to convert, just use a brake controller resisitor (polarity is not an issue).

Willie

Twas a Plymouth, with a negative ground. Brake resistor- nice idea! Ballast resistors can get hot.