MBF Posted April 15, 2007 Report Share Posted April 15, 2007 i need to get the gas guage in my 36 plymouth repaired and converted to 12 volts-any ideas who does this type of repair / conversion? MBF Quote Link to comment Share on other sites More sharing options...
Guest AZMoparMan46 Posted April 23, 2007 Report Share Posted April 23, 2007 All you gotta do is put a resistor from Radio shack behind the gauge, thats how I got mine to work. I forget which one but I'll go out and find the number off it Quote Link to comment Share on other sites More sharing options...
msawdey44 Posted September 6, 2009 Report Share Posted September 6, 2009 Try doing a search on eBay for "voltage drop" or "12 volt conversion." What you're looking for is a little voltage regulator diode giving 6 volt output. I'm not sure you can get sufficiently accurate voltage dropping on a very low-draw item like a gas gauge by using a resistor. I think these diodes are what was once called a "Zener diode." I got one for about $5 on eBay that has worked fine for dropping the voltage to the gas gauge on my '50 Dodge. I have (tried) to attach a picture--found on eBay as "12 to 6 Volt Reducer Dash Gauge Voltage Drop." As you can see from the band at one end, it's a diode, rather than a resistor. You could probably find the same thing at Radio Shack by looking for 6 volts output and an input range that covers 12 volts. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted September 6, 2009 Report Share Posted September 6, 2009 most voltage drop solid state device use the 6.6 or 7.2 volt zener diode and a couple of dropping resistors of 2 watt variety in parallel to get a 4 watt capacity needed for current drop and heat disappation..I configured one of these long ago for my Sunbeam Tiger as the Lucas original is well.."Lucas" need I say more..in modern configuation this one device is the regualtor for both fuel guage and temperature guage regucaltion Quote Link to comment Share on other sites More sharing options...
TodFitch Posted September 6, 2009 Report Share Posted September 6, 2009 ...snip...I'm not sure you can get sufficiently accurate voltage dropping on a very low-draw item like a gas gauge by using a resistor....snip... A zener diode based device is a more robust solution. But the voltage on the gas gauge is not critical as long as it is low enough to not damage it. All the gas gauge schematics I recall seeing showed the system was designed to work over a fairly wide range of input voltages. On the "one wire" type systems the variable resistor in the tank is one leg of a bridge network so all that matters is the relative resistance not the absolute voltage. On the "two wire" type systems you are heating two elements in the gauge head based on the relative flow of current on the two legs going to the tank. Again the relative current is what matters not the absolute voltage applied. So a simple resistor to provide somewhere around 6v should work. Having said that, I'd still probably go with a zener based system that could provide reasonably well regulated voltage. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted September 6, 2009 Report Share Posted September 6, 2009 the two wire heated model has a built in 5 volt regulator circuit.. Quote Link to comment Share on other sites More sharing options...
Jacqualine47 Posted September 8, 2009 Report Share Posted September 8, 2009 If you are really concerned about it and have basic soldering skills, here is a link to a schematic for a 6v solid state regulator rated at 10 amps: http://www.studebaker-info.org/tech/6-12V/6-12-6.DOC You can put it together for less than what a ready made resistor (like a Runtz, made specifically for a gas gauge and costing about 10 dollars) would cost. It can be used to power your gauge, clock, and radio (yes - I said radio... to get that working after conversion, just open up the radio case and check to make sure that the vibrator is a mechanical one rather than solid state... if its mechanical then the old tube radio doesn't give a darn about polarity - according to the antique radio gurus at the antique radio forum anyway - but if it is a solid state unit, you'll just want to pull it out and replace it with a 6v neg ground solid state vibrator. Don't stick in a 12v vibrator unless you know how to rewire your 6v tubes in parallel). Of course, it being a 36 you very much may not have a clock or radio LOL... in which case I'd just buy a 10 dollar runtz, put it on the back of the gauge, and be done with it. Just do a search for 'runtz' on ebay motors and you'll find a ready-to-go solution. Quote Link to comment Share on other sites More sharing options...
steveplym Posted September 10, 2009 Report Share Posted September 10, 2009 Get a runtz fuel gauge resistor. I bought mine from speedway and it was easy to install and works like a charm. http://www.speedwaymotors.com/12-Volt-to-6-Volt-Reducer,2374.html 1 Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted September 11, 2009 Report Share Posted September 11, 2009 The prior owner of my car did a half fast 12 volt conversion. I have not found any voltage reduction device on my gas gauge (P-15 3 wire) but it works well at this time. Quote Link to comment Share on other sites More sharing options...
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