Thread: How to hook-up gas gauge??

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My gas gauge is not hooked up in my car. I have saddle tanks that have 1 wire from each one coming into the firewall. I guess my big question is how do I hook the gauge up to the toggle switch that controls which tank I'm using?

While "we" are waiting for a circuit diagram, maybe you can answer a question for me. I am considering saddle tanks for my '29 roadster but I have a bumpy driveway about 400 feet long and about 4 1/2" clearance on the dropped front axle. As with the scrub line of the wheel rims do your running board brackets hang lower than the bottom of the tanks? I am wondering whether the effective scrub line for the tanks is above the clearance of the front axle and the running board braces? Also does your car have simple shields between the mufflers and the tanks? I have seen simple aluminum sheet heat shields between the mufflers and saddle tanks but I wonder if these are absolutely necessary or just a good idea, it does get a little tight between the A rails.
While I too would like to hear how others have done the switch, my first guess would be to find a two position switch from Radio Shack which should have three connectors. The common (middle?) lead should go to the gas gauge and the outer leads should connect to a tank, one on each side. I guess the question is what is the nicest switch to go with the rest of your dash.

Don Shillady
Retired Scientist/teen rodder

My tanks hang very low. Actually a little lower than my boards. To my knowlede there are not any shields, I will double check for you. The switch is realy not an issue because they are fairly hidden.

Assuming you've got two senders, one in each tank, and no "equalizer" connection between them to keep the fuel level even in each (which would only need one sender). All you need is a switch that has two "on" positions (up/down, left/right, however you want to orient). The switch completes the circuit, so one sender to one side of the switch, the other to the other. Then to the guage, it's only going to read the circuit that's "live".

Don, with your ground clearance issues you may want to reconsider. You could mount a verticle tank behind the seat and route the filler to the tulip panel (personally I don't care for the filler in the trunk thing). Using a flush filler door it would hardly be visible. Remember, if the front or rear wheel drops into a low spot the clearance at the center of the car is reduced, so I don't think you're going to have space to spare.

Thanks Youther and Bob. Saddle tanks are only one of several possibilities. Bob suggests a fourth possibility after saddle, '32-style or in the trunk. I don't like the trunk access either, especially if the battery is back there too. Good idea Bob, with a hidden or flush filler right above the drip rail it is less likely to spill gas on the battery, although I plan a covered box for the battery as well. The '32-style recalls the "Pinto-bomb" rearend collision problem while behind the seat puts it closer to the passengers, but further removed from either front or rear collision. I don't get to many shows and then they don't necessarily show you what is under the roadster seat very often but at the moment I am working on spatial problems with the master cylinder and realize I will have to cut a hole in the floor just to fill the M.C. Just for memories I recall my stock '31 A had the battery in the floor, but even with tall 19" wheels it would occasionally scrape the bottom of the battery box on something, so the battery will have to go in the trunk AND since this is probably my one and only total build I might as well go for a rumble seat. I suppose if I only intend to put two kids in the rumble seat for parade duty there will be room for a battery box and a gas tank just behind the front seat. Then that means a stock appearing external spare mount! Just thinking out loud and I appreciate Bob's experienced answers. Youther is having all the fun just driving his A and he doesn't have to worry about rain either. If I had my old '31 Fordor back again I would be glad to modernize it (with a green plastic roof panel for a super sunroof), but for now I just got to finish this roadster! Obviously if/when I get it finished it will have been due to a lot of help from members of this Forum, thanks.

Don Shillady
Retired Scientist/teen rodder

Don, I guess I'll make the highjacking of Youther's thread complete. First off, I'm not big on rumble seats, so I'll just throw out some things to think about. Of course it's your car so you choose. Putting the tank and batt behind the seat pretty much eliminates any leg room for the rumble seat area, and that in turn means you have zip for luggage either. Small kids could sit on their legs for these parade moments you're contemplating, but then you also have the issue of them getting in and out without harming your paint. All in all, in my mind anyway, the notion of the rumble seat is nicer than the reality of it.

One way to gain some batt space is to use an Odyssey Battery. Foot print is roughly 6.5 x 7 inches for a 925ah batt, at under 6" high. They're dry cell and can be mounted in any direction. A tad spendy compared to "normal" batts at your local auto parts place, but a real space saver, and easier to pull out if necessary. As you already are aware, under the floor there's precious little space with dual exhaust, so minimizing the above floor loss is important.

Below is a pic of the master cylinder access in my roadster just to give you an idea. Simple piece of sheet stock with a short "piano" hinge spot welded. You may have to beat your upholsterer around the head and shoulders so that he doesn't glue down your carpet as they are wont to do!

Thanks Bob, that is a neat installation for M.C. access. Just to keep Youther in the picture, I wonder where he put the battery in the sedan?

Don Shillady
Retired Scietist/teen rodder

"Don, I guess I'll make the highjacking of Youther's thread complete." LOL!!!!

Hijack away bud, you guys gave me my answers to my question, so I don't need the rest of this thread..LOL!

"Just to keep Youther in the picture, I wonder where he put the battery in the sedan?"

The battery is located inside the car in the very rear up against the rear wall. I'll take some pictures of the location and of the tanks this evening for you.

Here are the pics, the first is the front of the gas tank and boards.

Next, a pic of the box covering the battery. As you may or may not know from my prev posts, the rear is tubbed and it currently has no back seat. I want to change that though.

The battery uncovered.

And one more of the tank from further away. I will jack the car up tomorrow and snap some pics underneath.

Man, that is LOOOOW. Are the tanks snugged up against the frame as far as the'll go? I had poly saddles on my "A" sedan, and the bottom of the saddles was level or slightly above the bottom of the running board.

By the way, I noticed that you don't have washers on the outside of your 4-bar rod ends. Are you running that way, or is this a mockup? If you're running that way, you should put washers on for safety reasons. If the ball fails, the washer will keep the whole end from detaching with possibly unpleasant results. If it's a mockup, don't forget 'em later on.

Originally posted by Henry Rifle
Man, that is LOOOOW. Are the tanks snugged up against the frame as far as the'll go? I had poly saddles on my "A" sedan, and the bottom of the saddles was level or slightly above the bottom of the running board.

By the way, I noticed that you don't have washers on the outside of your 4-bar rod ends. Are you running that way, or is this a mockup? If you're running that way, you should put washers on for safety reasons. If the ball fails, the washer will keep the whole end from detaching with possibly unpleasant results. If it's a mockup, don't forget 'em later on.

I think the tanks are snug. I will have to check. I bought the car and did not build it.

I am driving the car almost daily as it is. What type of washers should I put on the rod ends?

Don, here are three pics that I took today from underneath my car. Hope these help.