Have you converted your pre 54 Chev to 12 volt for a CB or Stereo and discovered the fuel gauge doesn't work. Look at web page /~r1937/Fuel.htm> for the best and cheapest way to resolve this problem.

web site not found!

Hi Rex,
When you copy the address be sure and delete the symbols on each end and then it should work for you.

I have done this before and just added a 37 ohm 5-10 watt resistor in series with the 12 v dc line and it works just fine. A 30-35 ohm will work.

RexN - where would I find a 37 Ohm 5-10 watt resistor?

Fatfenders, I found several at a Commercial Electronics wholesale house, I would be surprised if Radio Shack carries them, but they surprise me sometimes.

Fatfenders , you can get a voltage reducer from 'Jim Carters' . They list a light duty one , for fuel gauge , at $US3-oo . and other options too .
Oh , that would be more in Cannuk cash , eh .
Still , it gives you a ball park to work from .

Thanks Mr.Mack, Dusty - I don't want to sound like a techno nurd but I wonder if it's simply a 6volt zener diode in the circuit? Any electro whizzes out there that could draw up a electronic diagram?

FF I don't think so, It must not only reduce the voltage but it is a resistance balanced circuit if you will look at the circuit diagram of the fuel dash gauge you will see what I mean.

Yes, I agree. I was trying to figure out how to electically isolate the circuit perhaps with capacitors - oh well I guess it's off to a ballast resistor - thanks all for your input.

FF I have a diagram some where I will look and try to find it and get back with you, Ok?

Mr. Mack, perrrfect. Yes please - I was a tech in the Navy about a million years ago and I'm sure with a schematic I could built one. Thanks a million more.

FF, you should have some e-mail messages from me, I think the 3rd try was successful, just don't try to send me a message from there (cctc)

The way I lerned it, R=E/I. If you want to drop 6V across the resistor, you need to know the current in the circuit. Seems to me that the current will vary depending on whether your tank is full or empty. I would prefer a regulated circuit as I don't like the idea of sparks in my gas tank. YMMV



-R

R.F. the fuel gauge is not your usual Variable Resistance circuit, that uses a volt meter to indicate fuel level, and I don't know why except to limit the amount of current in the variable resister, who wants sparks in the gas tank?, but if I remember correctly, the current is shunted from one winding that moves the needle toward (Empty) to the other side winding that pulls the needle toward the (full) side.and it really does work quite well as long as you DO NOT change the voltage too much upward, then it will burn out the windings in the gage meter and in the variable resistor. The 51 - 54 shop manual has a complete circuit diagram and a very complete explanation of how the fuel gage works.
That circuit diagram of yours looks familular, but I just can't quite place the application! LOL

Thanks MrMack for splaining it to me. I just get real twitchy when thinking about electrical potential bobbing around in a container of gasoline and air. I'll bet the engineers at GM spent a lot of time figuring out how to measure the tank level safely using a 6V source and I wouldn't want to second guess their design. Hence a 6V regulated supply would be best for this application.

-R

RustyFender, some times we start to see how much engineering goes into even an old car WAY back in 1950. I haven't had a problem since I rely on the original 6 volt system. I enjoy the ride and I use one of the all purpose 12v booster sets to power my CB and cell phone in the old car. I found one at SAM's that has a wet 12 volt battry, with booster cables, 2 12v access ports (lighter receptales), an air compressor, a 300 watt 110vac converter,a floresent trouble light, and a charger that connects either to 12vdc or 120 vac so I can charge it with my tow truck or in the motel room on tours. Cost = about $80 works great for me.

going to switch my 12 volts to 6 for the fuel gauge. I have purchased the recommended7806 voltage regulator. Does it go in the circuit between the switch and fuel gauge? That seems logical to me. Also what are the two symbols shown on the diagram located behind the fuel gauge?

M.S. I guess you have went to Lou's post showing the URL for a fuel gage circuit? If not please go there and see the pictorial diagram. Yes put the device in series with the wire from the ignition switch to the gage, be sure you get the wire from the ignition switch it wont do its job if it is on the wrong side of the gage.