I have a slightly different twist on the 12V electrical (gauges mostly) conversion. We're rodding our 51 F1 with a 302, but would like to use the original gauges intact as they all appear to be functional and are in great
shape. With the great info on the site, adapting to 12V shouldn't be too bad. I plan on trying to mate the original or reproduction senders as best as possible to small block mechanicals. Sacramento Vintage Ford has a
speedo adaptor cable that connects a C4 tranny to the original speedometer.

Any thoughs or suggestions?

Thanks in advance

 

The ammeter needs no conversion-you can use it as is. You just need to run the wire carrying th eload through in th eopposite direction.

Any of the gauges that you keep in their original state will need the original sending units. There are all in one voltage reducers you can use to drop the voltage to 6 volts on those, or you can use the small individual reducers on the back of each gauge.

The gas gauge is one that will need to be kept electric and in my opinion is best reduced with an individual reducer. Mine is like that and it works perfectly.

You have the option of leaving the oil and temp gauges as original electric and used with the original sending units - which of course would have to be adapted to the 302. Oil pressure is no problem as pressure is translated. Getting the temp sensor down into the stream with lots of adaptive fittings is another matter. In this case, you would use the oil and temp gauges as they are, with the original senders, and either use three individual voltage reducers (gas, oil, and temp) or one that is designed to drop all three.

I chose to convert my oil pressure and temperature to mechanical gauges by buying new mechanical Sunpro gauges and installing th eworks in the housings of the OEM electric gauges, and put on the original faces. You can't tell the difference and they work perfectly.

I have a gallery set up that is named gauge conversion or some such thing if you want to see pictures of the step by step process of converting to mechanical gauges for oil and temp.


Here is a link about installing the voltage reducers with drawings:

https://www.ford-trucks.com/forums/8...12-volt-2.html

PS Any speedometer shop can make you a speedometer cable that will connect the C4 to the OEM speedometer, AND calibrate it to the correct speed reading.

Welcome to FTE by the way

 

Thanks Julie.

Do you know about how much current normally goes through the ammeter during normal charging? I have a current-limited power supply that I was using to safely test each of the gauges. I pushed about 6A through and the dial hardly moved, if at all. It's probably higher than that, but I didn't want to risk it.

 

It varies. It will start out higher and eventually not charge or discharge - if you have your truck wired right. No need to test it further, if it moves at all it is working. The gauge is merely to show whether or not the system is charging or discharging, and in large or small amounts.

The exact specs are in the Shop Manual, under the Electrical System tests (voltage regulator output).

The stock F1/F-100 6 volt generator was rated at 35-40 amps. That's not alot on a 6 volt system. And 6 amps you used is probably about as much as your headlights would draw if they were on.

There was an option to either install or convert the standard generator up to 60 amp output - basically by changing the regulator and installing a smaller pully. My 100 amp 12 volt alternator will cause the gauge to pop up about 1/2 of th eway to the first mark after grinding on the engine on a cold morning. I estimate it is charging at about 5-7 amps at 14.5 volts.

So you aren't going to see a lot of movement. If you do while it's on the truck, it usually indicates that the generator isn't charging enough at lower rpm (typical of a generator, solved by an alternator) or the battery is not holding it's charges and needs to be replaced.