12 volt conversion

Chris Smith

Y and Z is building me a wiring harness for my 54 hornet and I mentioned I was going with 12 volt negative ground. They said I may have problems with my fuel and water gauges doing this. Anyone have experience doing this conversion? Should I go with 12 volt positive ground instead? If so, what do I need to do to make it work.

[Deleted User]

From the Ken Cates Website:



For ’51 and later cars, replace original instrument voltage regulator with NAPA/Echlin IR2. Note that this regulator is found on ’51 and later models only.

For ’48-‘50s, put a 15 ohm, 5 watt resistor in the feed circuit for the instruments. www.partsexpress.com is one source for these resistors .. look under “power

resistors” or “wire wound” resistors.



I did mine that way and both gauges work correctly.

Park_W

To the radio, I'll add the coil ... not that it needs positive ground, but it needs to be connected according to what porarity you're using. So if you keep the original coil and just add a ballast resistor, be sure to swap the coil connections.

Chris Smith

Thanks for the help guys, I have gone with a 12v fuel pump and had my radio converted to 12v,installed a one wire alternator already. I will likely go with electric wipers and add AC in the future. Looks like I will need to buy the gauge resistor and a bunch of 12v interior bulbs and I will be good to go.I have already installed halogen headlamps and 12v exterior bulbs. Am I missing anything?

Chris Smith

I just thought of one other thing to consider,the clock. Will it work as is on 12v (if its in working order?). Is quartz movement conversion an option and if so who does it and what should I expect to pay?

Unknown

the clock works fine on 12 volt as it is only used to rewind the clock in a split second. The clock actually runs on a spring.

464Saloon

You need a voltage drop for the heater motor. I have yet to find a 12v motor that will fit. Strangely all the ones made that will fit are still 6v.

Walt-LA

By all means, use a resistor with the fan motor. Put it in the box so that it can add to the heat! I ran my fan on 12V for one season- not much use here in LA, but it worked well enough, though it sounded like a banshee chorus on high speed. Nice and quiet on 6V. Also am using a voltage drop resistor with the clock winder, but did run on 12V for several years. Clock winders are amazing, they'll work on a 6V dry cell, or 12V car battery. Also had the starter converted to 12V, but understand not absolutely necessary. Might consider Petronix in lieu of points. Mine works great.



Dunno if Y&Z does it, but Rhode Island Wiring appears to use same gauge for 12V conversions as for 6V, so coud return to original if ever desired.



Walt-LA

464Saloon

Walt-LA wrote:

By all means, use a resistor with the fan motor. Put it in the box so that it can add to the heat! I ran my fan on 12V for one season- not much use here in LA, but it worked well enough, though it sounded like a banshee chorus on high speed. Nice and quiet on 6V. Also am using a voltage drop resistor with the clock winder, but did run on 12V for several years. Clock winders are amazing, they'll work on a 6V dry cell, or 12V car battery. Also had the starter converted to 12V, but understand not absolutely necessary. Might consider Petronix in lieu of points. Mine works great.

Dunno if Y&Z does it, but Rhode Island Wiring appears to use same gauge for 12V conversions as for 6V, so coud return to original if ever desired.

Walt-LA

Yes that resistor gets hot which is why I wanted to find a 12v motor. Mine is mounted just outside the box. I am not sure if it is safer or cooler in the box or out. Fortunately here in So Cal I rarely use it. Actually I rarely even use the car except for a special occasion.

Park_W

Here's a way to mount the resistor (or a cluster of them to achieve the right resistance value) in the box. Having a fair bit of the resistor body in contact with the box structure lets the box serve as a "heat sink."

[Deleted User]

Park W wrote:

Here's a way to mount the resistor (or a cluster of them to achieve the right resistance value) in the box. Having a fair bit of the resistor body in contact with the box structure lets the box serve as a "heat sink."

Do you happen to have a part number for the resistor used for the blower motor?

Park_W

The heater blower draws 6 amps on the high setting, so you need a 1 ohm resistance, rated at 50 watts or higher. Some of the "voltage reducers" from Whitney and others are 1 ohm units, and rated to carry about 6 A, so one of those would work. I got mine (shown in photo) from Parts Express (www.parts-express.com). I ganged four 4 ohm, 20 watt "wire wound" resistors together, connected in parallel, which produces a 1 ohm resistance with 80W capacity. The part # is #017-4. They're cheap ... 55 cents each in my catalog from maybe 2002.

464Saloon

Park W wrote:

Here's a way to mount the resistor (or a cluster of them to achieve the right resistance value) in the box. Having a fair bit of the resistor body in contact with the box structure lets the box serve as a "heat sink."

Would you have a part # for the resistor in the picture? I don't remember how I came up with the one I have but it is smaller than that one and gets unbelievably hot, so it probably isn't big enough. Since I plan to go to the Western Regional in Yosemite this year, I would like to get a better one in there. I may need a little more Weather Control at that altitude.

Thanks,

[Deleted User]

My '54 Hornet was converted to 12V neg. gruound when I got it and the guages work fine. I don't think they are as affected by polarity as some other components. Just make sure you hook up a good 12V to 6V voltage reducer in line with them (between the ign. switch and the guages). Walt Mordenti has a good line on an economical reducer....

Walt-LA

There are also some 5 V steady state sytems available on ebay for around $10.00. These consist of a Zener diode and resistor. Hudson gauges (fuel and temperature) from '51 - '54 were intended to operate on "5V "average" current, as described in the mechanical procedures manual. Polarity is not an issue, as the gauges and the sender are both resistors. In the case of the gauge, a resistor coil heats a bimetallic element which deflects moving the indicator.



Walt-LA

barrysweet52

I was told that if you get a narrow piece of stainless steel say 300mm x 20mm and bend it concertina style and attach it to your starter, it will act as a resistor and reduce the volts from 12V to around 6V . Regards, Barry