Gas gauge level sensor

[ChrisK]

I decided after careful consideration to put a gas gauge on the T. Other than the speedometer and a water temp gauge a gas gauge was a must.

My bucket is a Bobber configuration so I decided I would have to make a bung to weld in to support the level sensor. For the sensor I used a universal unit similar to one I had used on a boat a while back.

The gauge is an autometer unit. I wired up the gauge to make sure it corresponded properly with the level arm with small electronics jumper wire.

Next I made the bung out of aluminum and bored a hole in the round aluminum tank. Then I welded it together. Next I screwed the assembly to the tank and set the empty and full levels.

 

[railroad]

Nice job! Do you have coating on the alum tank? I bought and tried something called Quantum Seal for protecting some items and it seems to be good. It does cost about $90 a pint, but goes a long way. Something like Sharkhide.

 

[Hackerbilt]

Thats cool. I don't have a gauge, just a dipstick, so I have to be a little careful on long highway trips! (2 hour tank is how I treat it! LoL)
I'm thinking on going to a square tank with rolled corners and if I do, a gauge will definately be part of the mix.

Man...those brushed aluminium tanks stain easily and its not that easy to clean them after! I've thought about clearing mine...but that might open a whole new can of worms!

 

[ChrisK]

I will probably do something to keep the finish shiny. Like a clear epoxy or something. I did have a lot of cleaning set in the duty cycle of the welder plus the brushing I did. Scotch brite works great on this stuff.

 

[fletcherson]

Nice job welding!

 

[2old2fast]

Trouble w/a gauge in a round tank is it doesn't stay at full very long , stays between3/4 & 1/4 for a longer time , then 1/4 to empty pretty fast ....gonna take some getting used to ...
dave

 

[PotvinGuy]

Trouble w/a gauge in a round tank is it doesn't stay at full very long , stays between3/4 & 1/4 for a longer time , then 1/4 to empty pretty fast ....gonna take some getting used to ...
dave

Hmmm...must be a way to remedy that. Lemme think about it a while.

 

[mountainman]

Trouble w/a gauge in a round tank is it doesn't stay at full very long , stays between3/4 & 1/4 for a longer time , then 1/4 to empty pretty fast ....gonna take some getting used to ...
dave

Absolutely correct. Standard sender in a round tank is only correct 3 times....full, half and empty. Only 50% better than a broken watch.
If you have trip odometer, use it to correlate the actual miles left at the 3/4 and 1/4 mark. Difference at 1/4 is only about a half gallon on a 10x33 tank (10-10.5 gal with available tank end shapes) but would make for a long walk if you were pushing that last 1/4 tank.

Potvin, there are tubular magnetic senders that can be adjusted to get exact measurements. Probably have to custom build for small tank.

BTW.....car that I am building now will not have gauge. I have found that I trust/use the trip odometer more than fuel gauge with small tank.

 

[railroad]

You guys forget the human ability to learn. I have a wedge shaped tank, large at the top. When it gets to 1/4 it is time to fill up. If you want to learn where empty is throw a gallon jug of gas in the seat and cruise on.

 

[ChrisK]

Remember those old gm cars where you would go past full and it would give you 3/4 of the range before you got to half. Then half to empty was like only 75 miles!

All gas tanks cheat a little. Probably the best is a perfectly square tank but the gauge itself is an D'Arsonval arc so its really only accurate in the middle of the arc.

The round tank will most definatly read in error again the middle will be the most accurate. I just need something to look at to see where I'm at.

 

[fletcherson]

You could do like me on my bike, I keep a half gallon in the bags, just in case... I hate being stranded!

 

[PotvinGuy]

Hmmm...must be a way to remedy that. Lemme think about it a while.

Well, it is kinda messy. Here is some info: Car Talk cylindrical fuel tank problem
And as ChrisK alludes, the sender and gauge have some nonlinearities too. Now for a large fee I could design a gadget that would compensate for all the errors and the gauge would indicate exactly how much fuel you had. The gadget itself would be cheap, but the R&D gets you. I carry a stick to check the fuel level in my oddball tank.

 

[ChrisK]

An odd little tidbit-Greyhound always ordered their buses without a fuel gauge. They would always add at their next depot. When we converted a bus into an RV a few years ago we made sure we bought one with a fuel gauge. Those ex-greyhound buses had about a bijillion miles on them.

 

[Zandoz]

Thats cool. I don't have a gauge, just a dipstick, so I have to be a little careful on long highway trips! (2 hour tank is how I treat it! LoL)
I'm thinking on going to a square tank with rolled corners and if I do, a gauge will definately be part of the mix.

Man...those brushed aluminium tanks stain easily and its not that easy to clean them after! I've thought about clearing mine...but that might open a whole new can of worms!

Hmmmm...I've not thought of the tank staining issue. I have been considering the possibility of painting the tank with the engine/accent color. I wonder if a couple coats of POR 15 and their engine paint would work.

Trouble w/a gauge in a round tank is it doesn't stay at full very long , stays between3/4 & 1/4 for a longer time , then 1/4 to empty pretty fast ....gonna take some getting used to ...
dave

Part of my KISS campaign is no dash mounted gas gauge. I'm planning on getting a tank with a sending unit bung, then using a Moeller sight gauge in place of the sending unit. I'd say that close to the majority of the cars I've had go through the last quarter quicker...so I just use the gauge 1/4 tank reading to trigger a gas station quest.

 

[fletcherson]

Mount the tank verticle and the gauge will be accurate, lol... I plan on a fuel gauge, but will use it as a back up to the mileage method. I do fine on my bikes, etc, if I ride real hard its off a little. The big thing is if I venture further than I expect or in a new area with few gas stations. I know the big block will not let me venture too far from a gas station, maybe a tanker trailer for long hauls will be on the table... Did anyone try one of those long, thin under floor tanks that were being promoted on here last year? I thought about incorporating something similar in conjunction to the round tank to add some range. I'm not sure how much room I'll have for it yet.

 

[ChrisK]

In choosing what gauges I was going to utilize besides the speedo I thought about road tripping. Being a Chevy 350 I've had junkers I owned with that motor that seemed to run at times with just a quart and a half and 10psi oil pressure. Quite the oppisite of fords I owned(sbf). Those things ran real high pressure. So oil pressure was the least of my concern. I thought about a tach but I'm literally sitting on top of the thing and I can reasonably guess the Engine speed between idle and valve float. With the small battery an ammeter is going to be useless so I nixed that. So it came down to just two-fuel and temperature.
If I want more later I can do and engine mounted pod.

 

[fletcherson]

I like seeing the gauges, and knowing what is going on, not so much for moment to moment data, but to compare long term, I feel like I have a idea of how things are wearing, or foresight about potential issues. Also if something doesn't feel or sound quite right, the first thing I do is look at the vitals, so to speak. Just my preference. I get the minimalist thing too! The fuel gauge is one I have thought of leaving out, but when looking at packages, it's not much different with or without one, and I plan on full instrumentation. A low fuel light would probably be more than adequate, just a warning to look for a gas station. If I had to delete one gauge due to space or the like, I would do a tank mounted site gauge and maybe a idiot low fuel light.

 

[choppedtop]

I like gauges too. I am a gauge checker, mainly to see what is normal, for my engine. If there is a abnormal reading, I may be able to find out the cause before maybe ruining something. Fuel gauge is not all that important, as I know on each of my hot rods, the minimum distance I can travel. 150 miles is the minimum, that I can go if driving 75 to 80 mph for around 100 miles.If I will keep in the 55 to 60 mph range, I can go 200 miles. Don't do that very often.
Lee

 

[2old2fast]

I wouldn't leave the driveway w/o oil pressure , water temp. & voltmeter... fuel gauge is nice , tach& speedo for me are req'd..
dave

 

[Zandoz]

I picked up a couple pairs of no-name NOS Speedos and tachs, and I've found that AutoMeter makes a typical under dash 3 gauge panel that is a close enough match. This works out well, since from the beginning the plan has been for some type of sight gauge on the tank, instead of a a dash mounted gauge.

Recently I ran across the Moeller sight gauges...

They come in a variety of models for different tank depths. If not a direct fit for standard tank sending unit bungs, it does not look like adapting would be hard. If positioned on the right end of the tank, it seems like it would be readable from the driver's seat with an over the shoulder glance. Also, there is a conversion capsule to make these units into 33-240 ohm senders, if a dash gauge is wanted sometime in the future