what ohm rating sender does one run with this early stewart warner gauge? i don't have one yet but am trying to decide if i want one. i have the matching oil pressure, temp, amp and vacuum gauges. i didn't need one at first because i was running a float style sight gauge on the tank. now that i'm sticking the tank inside the turtle deck, i need something visible from the driver's seat. the sending unit on the tanks i'm looking at are a modern 0-90 ohm. i know this gauge is hard to find, i know if i find one it's going to be pricey. if it won't even work with a 0-90 ohm sending unit, i might as well by a modern gauge and mount it in some out of the way location so it doesn't clash with the vintage stewart warner line up. or do i mount it with the other gauges with hopes of finding one and eventually swapping it out and change the sending unit in the tank?
With todays fuels I would get an ISSPRO floatless sending unit regardless of what comes with the tank. They are available in all of the ohm ratings. SW was available at times in different ohm ratings, so I think the answer is "it depends". If there is no p/n or information on the gauge, you could get some cheap resistors and just try them out on the ground side until you find empty and full.
I dont know the OHM rating for that gauge, but TANKS inc will sell you a universal sender in any ohm range needed.. I got one from them that works my stock 39 fuel gauge perfect.
240 empty 33 full was pretty common on SW senders. As far as I know, only GM used 0-90, and that was from the mid 60s and newer. you can get one of these and see how it works https://www.tanksinc.com/index.cfm/...t_id=748/category_id=184/mode=prod/prd748.htm
It's not a direct answer but I did build this thingie once that will tell me what ohm range I need for my vintage gauges: https://www.jalopyjournal.com/forum...-will-work-with-my-dumb-gauge-thingie.862020/
I couldn’t find the ohm listing but did find the fuel tank sender numbers that may be able to be cross referenced. Cost on the 688-A gauge was a whopping $9.40
To find the oms needed , Could you use a Rotary ohms ( like a volume switch) bench testing ,Connect rotate to full , take a oms reading , then rotate to Empty,Take a reading , would that tell you the oms the gauge works on ? E -F
Most volume controls are 0-10,000 Ohms, or more, which is kind of tricky to get adjusted to the low resistances that gauges use. A 300 ohm rheostat would probably work better. But I just use various resistors from my old resistor ***ortment when I need to test gauges.
might end up trying this but dammit jim, you have to change your avatar. it looks like a guy i went to school with and i keep thinking, when did he join the hamb, he wasn't into cars
If you take a variable potentiometer and hook up a 12 v. battery to it and the gauge, you should be able to figure out what range it operates in, and also whether it's straight or reverse polarity. You can buy a 0-100 ohm pot at most electronic suppliers pretty cheap for testing. That's the same thing I do, but with a lower range potentiometer. You can also determine if it's reverse polarity or straight if you swap the leads from the battery.
After reading this thread I remembered the HAMB post from Dreddybear on the gauge tester he built. I had ordered everything I needed to build one but totally forgot about it. Luckily I found the parts and decided today was as good as ever to make it before I forgot again or lost the stuff all together. It works great. I was able to check the ohm range of this 1950 Chevrolet fuel gauge. I took a video by couldn’t figure out how to upload it.
Maybe a long shot, but could you send it to Tanks,Inc and ask then to match it to a sender? They're pretty good guys.
The Jalopy Journal
