1950 Dodge Diplomat with Gyro-Matic transmission.

The car currently is running on a 6 volt positive ground system.

I would like to change to 12 volt negative ground system.

I understand that lights, motors and radio will have to be changed or protected and new generator will be required and regulator. What do I have to do with the Gyro-Matic transmission should I change to 12 volt negative ground.

Any comments appreciated.

Thanks

Bob

The transmission is shifted by 6 volt solinoids which have no 12 volt replacements. Do not change to 12 volt. Car works fine with a good 6 volt system with correct battery cables and good clean tight connections. If you want to use a 12 volt accessory there are converters that can accomodate one or two accessories. Most people make mistake of using 12 volt battery cables on these older cars. A 12 volt cable can not carry the amperage required by a 6 volt system. Be sure your primary battery cables are at least 1/0 (one ought) guage. Most 12 volt cables are 4 guage, about half the size of the 1/0.

I just bought a 52 Imperial and the first order of business is a complete brake job replacing master cylinder, wheel cylinders, shoes and all hoses. At the same time installing a new battery of the correct size and new 1/0 guage cables. 6 volt cables are very sensitive to loose or dirty corrodied connections and internal corrision.

Listen to Mr. Call. One of the problems with your Dodge is that it was so much better built than cheaper cars like Chevrolet, Ford etc. By that I mean your car has or could have, electric windshield wipers, built in heater with electric fan, the electric controlled transmission, in addition to radio, lights, etc.

This makes it much harder to change to 12V without doing a half assed job. We frequently get questions similar to yours, where a new owner is trying to fix a car like yours that the previous owner tried to change to 12V and couldn't figure out how to finish it, and eventually abandoned the project and sold it.

Of course once a car is lobblollied about, messed up, wiring hacked, parts wrecked or thrown away it is a big job to change it back to where it was stock.

MUCH easier to keep it 6V which works PERFECT if everything is in PERFECT shape. Seriously, they never went to 12V because of cars like yours. They did it to keep up with starting the big high compression OHV V8s and to handle the new accessory loads of the fifties of power windows, power seats, air conditioning etc.

As your car has none of these things the 6V system is plenty good for your car. If something is not working correctly it is much easier and cheaper to fix it that tear up your whole car and replace everything.

Now having said all that, if you REALLY want 12 volts, don't be a sucker. Sell that heap and buy a newer car that came with 12V. Don't waste hundreds of dollars, or thousands of dollars, and hours of frustration, when you can just buy a car that is already 12V.

Speaking of starting a 6V car.... I just sold a 1949 Chrysler Windsor six. This car has been off the road and out of commission since 1965. I got it running a couple of months ago and the engine is a honey.

Here comes the story. A couple of weeks ago a fellow came along who wanted to buy it. The car was in my garage, but had not run for months. I put a heater under the oil pan, put a freshly charged 6V battery in it and it fired up with no trouble. Let it warm up for 15 or 20 minutes and shut it off.

4 or 5 hours later Mr Buyer came to see the car. I didn't even open the door, just reached in the window, turned the key and VOOM it fired up in 2 seconds. This was on a day that was -10 Celsius which is about 15F.

The point is, your car will start and run perfect, red hot or stone cold, just like when it was new if it is in good repair. If something is not working right it makes no difference if it is 6v or 12v, just fix it right and your car will work grand for you.

5 dub ya, NAPA stores have the correct size battery, Group 2, for your car. Stock number is BAT 7204. List price is $49.50 plus core charge and taxes. If your local NAPA or other parts stores don't have 1/0 gauge battery cables they can be found online.

TSC and other farm equipment stores stock 6 volt batteries too. A lot of farm tractors run on 6V with no trouble.

The car currently is running on a 6 volt positive ground system.

I would like to change to 12 volt negative ground system.

I understand that lights, motors and radio will have to be changed or protected and new generator will be required and regulator. What do I have to do with the Gyro-Matic transmission should I change to 12 volt negative ground.

Any comments appreciated.

Thanks

Bob

Thank You for all of your comments. (Good comments) Everything works just fine with the 6volt system, radio clock lights, including the 6v led taillights I installed which improved the safety factor significantly. The issue the Wife wants AC, therefore the 12 volt issue.

5Wbob

Buy a newer car. I am serious. Or, go ahead and change to 12V if you are stubborn but if you succeed, come back and tell us how you did it. I have been working on cars for 50 years and know the old Chrysler products inside and out. We have had this inquiry many times but so far as I know, nobody has ever succeeded converted a Gyromatic trans equipped car to work on 12V. Although a few have tried.

If you put a gun to my head I would install a 12V alternator, and install 2 6V batteries in series. Use 12V to run the AC and run the rest of the car on 6V. Possibly changing the lights to 12V but nothing else. In other words, have 2 completely separate electrical systems for 6 and 12 volt.

But I think I would just sell the car and buy something newer with 12V and air. Much as I like the old flathead 6, they are no ball of fire. I hate to think how slow one would be with air.

I just got done with a 46 Chrysler that a meatball mechanic tried a 12V conversion and couldn't get it to run.

It all started when the mechanic put in a new 6V battery (backwards) and the battery would go dead when the amp meter was showing a charge, so it "needed the conversion".

The car is now back to 6v positive ground with a swamp cooler window unit for cooling. In the late 1950's there was a company made a floor mounted unit also.