So if I dont drop the voltage period, I can use 12v guages? I have the truck on a 12v system now. The 6v sending units are $80 apiece, the 12v sending units are $15 apiece. If I can use 12v sending units, what do I use? Thanks for the info.

Motivated again after 4 years of my 51 Merc sitting, poor girl..
 

Julie, back on this site, cause its time to bring my ole 51 Merc M1 to life. Sadly I have been ignoring my truck for some time and have my mojo back into restoring my truck. This 5 year post on 6v-12v conversion for a 51 ford will not load on this site anymore.
Can you please hook me up with it, I'm a little sketchy on the guage hookup with voltage reducer and specially the Amp meter.
I dont even know if you have your truck anymore cause of the age of this post. My fingers are crossed and hope you can help me out, Cheers!
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This sbject comes up quite frequently, and for those of us who have spent a lot of time on the site, we know where all the little tidbits are and how to find them. But I haven't been here so long that I have forgotten how difficult navigating this site can be at times.

The link in the quote above will send you to some generic electrical drawings I drew up when I rewired my 51 F1. Most folks find them helpful and they will work on just about everything that had real wiring.

I would suggest that there are TONS of prior discussions about 12 Volt conversions, some of the little quirks that folks have found, and just about everything you should need from an info standpoint.

I would go to the main page for this forum and in the "Search this Forum" box type in "12 Volt Conversion" (be sure to include the quotation marks. Our search function has become almost disfunctional with the last site upgrade but yo ushould be able to find a lot of posts. If yo uhave a problem, come back and I'll see if I can find them and either cut an past the info into a post for you or paste down some links. And if yo uhave any questions, I'll be back to help.

There are a number of growing options for your generator. You should be able to buy a 12 volt generator at any NAPA or Kragen. You will need a matching 12 volt Voltage regulator and will need to polarize the field of the generator after it is installed but before starting the engine. That is a simple procedure where you simply remove the wire from the field terminal of the regulator and momentarily touch it to the battery terminal of the regulator - then reconnect it.

I agree with the folks above though. If you are going to the expense of putting on a new charging system - I'd recommend an alternator instead of a generator, and get an alternator that is of the variety that has an internal regulator - the proverbial "one wire" alternator. This will negate all the wiring over to a regulator and is very reliable. GM alternators are built this way, and there are other restoration shops that carry them - such as LMC, Tuff Stuff, and others.

For your conversion, you will need to change all your iginition parts (coil, condenser, points) you should (but I've heard you dont necessarily have to) change out your starter and starter solenoid. If yo uhave electric wipers you will need a 12 volt wiper switch (but you probably have vacuum wipers) and if yo have a heater, yo uwill need to install a "Vol-ta-drop" to reduce your new 12 volts back down to 6 volts for you r heater - as 12 volt heater motors are not available for the Magic Air heaters (but ARE available for others). If you get a 12 volt heater motor you will need to get a switch matched to the motor. Replace the cigar lighter with a 12 volt unit. All of your light bulbs will need to be replaced. and you will need to put resistors on the backs of your original gauges to get them to work right - the conversion is simple and effective. All the rest of your switches will work fine through the conversion.

I just checked the search function using "12 Volt Conversion" and all the posts showed up. So, just go there and pick the one that seems applicable. If you decide to go with a one wire or GM type alternator, let us know and I have links to installations procedures as well.

Welcome to FTE and have fun!

PS When yo ulook at teh titles of the threads that come up from your search, and some of th etitles seem a little weird like "Fordomatic Transmission" or "56 Wiring Harness" be sure to look at those as well. VERY OFTEN we get off on tangents, or the conversation evolves into wiring situations. Also remember that the wiring in these truck with rare exception is VERY fundamental and almost all th esame between models and years - this is especially true of the Bonus Built Trucks (48-52)[/QUOTE]

I think you forgot to add the links?

Julie: I used your instructions to install dropping resistors on my 1951 F1 pickup. After wiring, upon turning on ignition fuel gauge read properly. Oil pressure and temp immediately pegged out max. I reversed the resistors on the gauges and the same thing. Any recommendations? I am new to the forum, so can you email me at idaholc@aol.com

"Julie" is long gone from this site and will never return (VERY long story!), so don't expect a response from him/her.

Welcome to the forum!

Dropping resistors aren't likely to work (sounds like they aren't). The usual way to reduce voltage down to 6v is to either use a zener diode-type device (Runtz is the most popular) or a CVR/IVR (constant voltage regulator/instrument voltage regulator), or an electronic regulator.

Runtz are expensive, you need one for each of the three gauges.
Runtz 12 Volt to 6 Volt Reducers - Speedway Motors, America's Oldest Speed Shop

Ford used CVR's for about 10 years, you can find them in '57-mid-60's cars at the boneyard, or buy one from NAPA, believe it or not these used to cost $15, now they are out of sight:
http://www.napaonline.com/Catalog/Re...Dp%3d3%26N%3d0

I'm using this electronic, which serves all three gauges:
http://www.ebay.com/itm/Ford-Instrument-cluster-voltage-regulator-5v-SOLID-STATE-LIFETIME-GUARANTEE-/281147134257?pt=Vintage_Car_Truck_Parts_Accessories&hash=item4175acd131

I wonder if Julie has ever tried to get back on here again. She/He was successful
with Dan for a while. But with there/It's attitude I am pretty sure we could figure
It out.

I used the Runtz voltage reducers and this was the result. I have since stumbled upon this Dennis Carpenter product that I will try.

Voltage Reducer | Dennis Carpenter Ford Restoration Parts

I'd be curious to see how this one works. Any idea what the 3 wires are for?

I'm about to tackle a 12v conversion myself on a non-Ford.

Red to ignition, blue to split and run to each of Temp, Fuel and Oil Pressure. I am not sure of green, but I assume to ground. If you click on the link there are two images you can enlarge. One is the wiring diagram.

That appears to be electronic, potted like semiconductors. They do need to be grounded (on Ford CVR units the case was grounded) so the green is likely a ground.

I have installed the Dennis Carpenter voltage reducer that he sells for 1948-55 six volt gauges and I have the same problem as when I installed the Runtz voltage reducers.

With ignition off all gauges read zero. When ignition is turned on, fuel goes to appropriate level, but temp and oil pressure both max out.

Any suggestions?

Temp should read Hot with no power to it (key off). It will also read Hot on a V8 if the single-wire sending unit has failed; do you have a V8 or 6?

Take the wire off the oil pressure sending unit and isolate it (away from ground). The gauge should now read zero with the power on. If it still pegs, the gauge unit is wired up wrong or the wire is shorted to ground between the gauge and the sending unit.

Julies Cool F1 , I have a copy of your wire diagram and will use the two volta drops and three reducers like you suggest but noticed you drawing is + ground. my truck is - ground. is everything going to still be wired the same? I cant figure out how to usethis site. Just need to ask that question.

Miss Cool F1 (Dan) is no longer with us.:-roll
But he/she's diagram is still as good as it ever was.
Just remember to change polarity to what you have
and you will be good to go.