If I could fix ONE thing on my truck it would be the fuel tank/gauge situation. First off I do not have any fumes at all inside my truck so that isn't my reasoning. Second, I don't trust old gauges. I have run out of gas three times and it is embarrassing so now every single time I leave in the truck I put at least $10 gas in it. More if I'm going farther. I was talking with Ben (Ben chime in here if you will) from Austin and they put the mustang tank under their truck and did some mods to the sending unit because they couldn't get a matching gauge for the sending unit.....I may be missing something but here is what I found. I'd like to know from those of you that have done this mod WHY this wouldn't work??? I found the tank at Rockauto even though I used a Summit link just for this post. It's the same tank. Also found the sending unit that everyone matches up to that tank for a '70 mustang. It has an ohm range of 75 ohms empty to 10 ohms full. Lastly, Summit has numerous gauges in that ohm range to choose from. I'm just leery because I've hear lots of people say they used that tank and couldn't match up a gauge for that sending unit. What am I missing?
Some answers ahead of time.....I don't want to get in a discussion on WHY I want to move the tank...waste of time. I just do. Conversely....IF I could put a modern sending unit in the stock tank and leave it in the cab I might be alright with that IF I could match up a modern gauge.
Simply put, why won't the three items below work together to solve this problem...and if the answer is “they will” then why all the posts I've waded thru and never once read about how simple this is? Makes me feel I'm missing something.
Thanks guys!!


1970 Mustang 22 Gallon tank
http://www.summitracing.com/parts/sd.../model/mustang

1970 Mustang Fuel Sending unit for above tank
More Information for SPECTRA PREMIUM / COOLING DEPOT FG86C
75ohms empty to 10ohms full (got this from a technician at the mfg company)

Fuel Gauge Selection for the above.
http://www.summitracing.com/search/d...y-10-ohms-full

 

Anything can be made to work, depends on budget and what you want to use as far as parts.
Assuming 12v this will let you use any sending unit with any guage, takes all guesswork out.

http://www.speedwaymotors.com/Fuel-G...ule,66534.html

I have also found aftermarket programmable gas gauges.

I have made my own sending units as well as used universal ones to make things work. Do you have your heart set on using a specific gauge? If so just figure out what sending unit you need and go from there. I like to use GM factory tanks and sending units which run on 0 ohms empty to 90 ohms full. I know I can either mod a factory GM gauge to work or dolphin gas gauges also use the same range. I think that speedway unit may be worth the money if you are in a spot where you cannot match up what you want, beats walking.

 

But all three parts I listed are matched up. The common "70 mustang fuel tank" tutorial on here that everyone refers to is my basis. My question was why given that we've all referred to that good write up that everyone always talks about trouble finding a sending unit to work and then finding a gauge to work.....took me five minutes. There must be some reason. I want to use that tank because it fits great. Therefore, makes sense to use the sending unit made for it. Therefore again, it took one search of Summit and there are 41 gauges to pic from. Somethings not right. I'd like those that have used this tank to tell me what I'm missing here. Thanks!

 

I did this tank mod on my 52, I think most people try to use the original gauge in the dash along with the mustang tank and sending unit, I know I did along with 6volts. It does not work right. Then when I went to 12 volts, I purchased a new gauge that matches the mustang sending unit. I mounted this below the dash along with a voltmeter gauge. It all now works for me.

 

Feel free to see the last page of my build I just updated some pictures of my tank. 22 gallon Mustang fit well with some modification.

 

Hi there,
I see no reason your set up should not work - but what do I know...
I do know that I did this modification to my vehicle with no hiccups.
Used AutoMeter gauges, sending unit and a tank from ebay.
A modification well worth MY investment.
Just do it.
Paul

 

I have had the same question recently. Ill be interested to see what people say.

 

Might ask these guys. They stock a ton of specialty Stang and Truck parts.

Genuine Ford Parts - OEM Ford Parts - BlueSpringsFordParts.com

 

I am going the other way. I am keeping the stock tank and I have a Stewart Warner gauge. I will be ordering the SW sending unit tomorrow and will see if I can adapt it to the factory tank.

 

Let me know how that works if you don't mind.

 

For those having issues with your stock fuel gauges and new tanks, it's because there are two different "languages" being spoken. Most modern fuel gauges and senders are simply paired ohm meters and variable resistors; the gauge measures the resistance of the sending unit circuit which changes with the fuel level.

However, our stock Ford trucks used a different language, named The King-Sealy principle. These sending units supply a full 6V through a heater wire in the gauge in the form of a square wave with the duration of the "on" being the variable determining the gauge reading. The longer the duration, the more fuel in the tank. It is this full 6v of current which heats the bi-metallic strip in the stock gauge that causes the gauge to read via a small gear train. Most (if not all) after market sending units are simply a variable resistor which sends a constant closed circuit of varying resitance to the gauge. Therefore, the sending units signal doesn't heat the bimetallic strip in the gauge as much making the calibration of the after-market sending units and the stock gauges nearly impossible to match up very well due to the differences in the principle of the signal.

Modern gauges are easy to pair as long as the sendig units full and empty ohm readings match that of the modern gauge. Some senders and gauges are even highly adjustable in this regard.

 

Hey Wayne,
We had the same problem you have - every time you fill it all the way up the cab fills with fumes. Very uncomfortable. Yes there are gauges out there that match with the ohms on the '70 tank. We just didn't want one odd gauge that doesn't match the 5 others in our dash - that's why we put the modern sender unit in the Mustang tank. Now all our Ford Classic series gauges match - looks right.

Good luck over there - Go for it.

Ben in Austin
1950 F1

 

For vintage styled gauges that will work with the mustang tank, im planning on using the new vintage woodward gauges. Theyre a little cheaper than some of the autometer guages but i think they actually look better.

 

I have a 1949 F1 that I just reinstalled the original gas tank back in the cab. This tank has 6 fastener holes on approximately a 3 1/4" diameter pattern. I am using Classic Instruments gauges. Their gas tank sending unit has 5 offset fastener holes on approximately 2 3/4 diameter pattern, same as the SW gas gauge send unit. Classic Instrument makes an adapter, part # SN-41, that adapts the new sending unit to the original tank. I have installed the adapter and sending unit with no problems. The gauge and sending unit came as a matched set so I see no calibration problems. I used their gauges in my 39 Ford Coupe and they work perfectly.
Ken

 

Some replies....Ben...I don't have fumes inside is what I said in the original post. Glad you found the thread though and let me know why ya'll did what you did.

Ken...thanks for the info. I did some investigating and here's what I found.

Classic Instruments adapter that you mentioned..


Classic Instruments assortment of sending units you can get (all I assume will bolt to that adapter.)


Looks like there is a sender available to match most any gauge you would want according to the chart.

One last thing. Notice in my original post I stated that "IF" i could fix one thing on my truck it would be this. I was sitting around thinking about this thread before I started it and was thinking of all the things I'd like to do to the truck. Then I remembered I have ZERO funds so that's why I started it with IF. Yet another dream of mine to keep me going.