The Stovebolt Site Forums The Shop Area The Electrical Bay Gas gauge 6v to 12v

A friend asked me if the sender couldn't just be disassembled and rebuilt using a different resistance value of wire. Answer is yes...I did this and posted the whole she-bang here a couple of years ago...explaining how I calculated the wiping arc distance, the length/width of wire for the proper resistance and even how I modified the wiper to have almost zero drag. I also showed how 2 different styles of wiper could be made and how using flat Kanthal wire (as far as I know in the history of the world it hadn't been done before it was done right here) would make it more accurate and less prone to failure. Quite a bit of work was poured into this.

As a side comment---not a rant, but just a suggestion---I believe we truly need to revisit our tech tips section. So much worthwhile information just drifts off and becomes only vaguely remembered and then is difficult to resurrect. Maybe have a section where topics like this could be posted and then amended, updated, corrected or enhanced by the original poster or by others...sort of like Wikipedia. We could call it Truckipedia and then folks would be able to quickly see what was there. None of us is getting younger and one day people won't be here to answer questions or answering may not be as easy for them. Some sort of encyclopedic compilation of information would be nice in my opinion and I believe it might even stimulate more involvement from the audience.

Anyhow, I did show how a 0 to 90 ohm unit was disassembled and rewound to become 0 to 30 ohm (see below...first image is the start, second the coil is re-wound and third the coil is in place and usable. That sender is still around here somewhere in a small plastic sack marked "keep this one---it works well." The whole exercise is a matter of measurement, calculation of arc distance and resistance/length of wire. In the last two images I showed how I could make a flat wiping plane that would start within a tiny hair of 0 ohms and finish at 30 ohms and be correctly linear. So as I said, "yes, it can be done." Fact is an impressively accurate unit can be made, but the issue is cost/time. Plus...and I've mentioned it here before...the AD gas tank isn't baffled, so even a perfectly accurate sender is only as good as the continuous sloshing of gasoline. I did design and begin work on a unit which would be 100% slosh-proof. 100%. It used a thin pvc tube (or thin brass tube, but I never found an affordable one) in which sat a circular float and magnetically operated off/on reed switches connecting to different resistor values. The problem? It works exactly like a modern led gauge...when the float goes down you don't know the fuel level has changed until the lower reed switch is actuated by the magnet and a reduced resistance value is "seen" by the gauge. So your needle goes from full to empty more or less like a man doing a slow wedding march down a flight of stairs...no movement for a while and then it drops a peg. If the AD tank had been set into the frame where it wouldn't be so tall, the reed switches could be set horizontally (using more switches and consequently more and closer resistor values) and the output would have been much smoother, but with so much height to deal with one can only do so much.