The Stovebolt Site Forums The Shop Area The Electrical Bay Mustang gas sender vs Chevrolet

I am finally going to put a gas tank under the rear bed of my 37 pickup to get the tank out from under the seat.

I've found a new 65 mustang gas tank for less than $60 bucks and think it'll fit. (got to do a couple more measurements)
Information
1937 gauge is original built for my 12 volts system.(Edit: sending unit is 30 ohms)
I do not know the ohms of the Mustang sender (Edit: mustang is 10 ohms full 75 ohms empty)

Question:
Is the mustang sending unit compatible with my Chevy gauge?...or do you think I'll have to change something?

Any help appreciated. I've wanted to do this for some time.

The new sender resistance value from empty to full will determined if the sender is compatible. If you can't find the resistance value of your old sender in a manual then you can measure it with a ohmmeter. You can also hook up a variable resister (0-200 ohms) with alligator clips to substitute for the sender. Just power up, move the resistor till the gauge reads m/t and full. Power off, read the resistance with the ohmmeter and you have it.
The new sender resistance value should be available from your tank vender.

Mustang? What about the risk of rust mite contamination?

Was your original sending unit accurate with your current gauge?
Do you know what the ohm range is for your old sending unit?
Measure it, and the Mustang one with a multi-meter to see if they match. If they match, your gauge will be happy.
Carl

beltfed/karl, My current sending unit is correct and has been for 15 years. It is a 30 ohms.

I know how to check them but I was just checking in before I lay out $$ for something that may not work and someone here may know why! I can ask the company but you know how that is going to work out and on a couple sites I checked it did not list the ohms of the 65 Stang sending unit....but rest assured I'll find out. I'm headed for research now.


EDIT: I found a tank for a good price on Rock Auto. However only one of their listed sending units gave the ohms which are Empty 75 Full 10 ohms. Looks like I'm going to have to figure something out.....as it will not be compatible with my guage?? Corect?
Any suggestions????

Thanks for your responses and comments.

Hy Achipmunk, does the F@#d sending unit use the universal five screw offset hole attachment to the tank? If it does you could simply swap your sending unit into the tank. Happy New Year!

Hey 3B, hope your staying warm.
The tank I was looking at on Rock Auto uses a sending until that has a lock ring......the tank I looked at Tank Inc. has one that the sending unit has the five holes with the two holes off set that you mention.
I'll check the one in my original 37 tank and see if the holes match.....the other "problem" may be that the mustang tank sits in the tank at about a 45 degree angle where mine is flat. However that does not mean I can't make it work though!!

More later.

I have bent pickup sender units to fit the tank in my Suburban. (bend the float rod) you may also use your sender unit and carefully weld/fasten it to the flange from the Mustang one.(if holes don't match) or, drill a couple new holes in your sender to match the tank!

Hey there Alvin, Just thinking out loud here.
1. Using your existing sending unit would be nice IF they are still available for when it goes bad. If they are not available it may change the approach.
2. It seems like your plan has too many bad problems. It seems like you should use a tank that has the 5 screw flange that is flat mounted, not 45 deg. Gives you a chance to find/modify a sender.
3. I have modified a sender for my suburbans/panels like Mike. Swapped out arms, bent arms, reposition the rheostat box, etc. Lot of work.
4. New tanks will be safe to weld on if some idea hits you there.
Like make a new sender hole (with a spacer for depth if necessary) or any other mod.
5. I would keep searching and also wait for other responses from early Chevy folks.
6. Can This work? With the stock sender or aftermarket one listed by them? (click on sender and see all the ohmages) What are the issues with this mounting in rear? If I know the problems with this type, I can possibly find one that solves the issue or know better what your ideas are.
7. Don't ever throw away your old sender if it goes bad, you need it to copy.

fuel senders - empty Ohm readings and full Ohm readings
(for different models/makes & years)

Bart/Tim, that is the very link (Tanks Inc) that I've been taking a new look at! Lots of info there.

I had only a few minutes this morning to chat with my nephew, who by the way wired both my 37 and 52 and is pretty sharp. As we talked he mentioned to me a way to adjust/set the gauge regardless of the type. Something they used when he worked in the R&D at Freightliner. I'm going to talk with him a little more to understand what he is talking about.....as well as talk to Mike Freeman or D&M Restorations next week to hear his suggestions and see what he can do.
I'm putting in quite a bit of time on contracting a couple houses right now but should have more time later this week.

I'll keep you guys posted and thanks for all the input. Somewhere in all this is the answer!!

Alvin, on my 59 I adapted a VDO sender, 0-90 ohm, to the stock 0-30 gage by adding a 100 ohm resistor parallel with the sender and some creative bending of the float arm. When the tank is full the gage reads a little below full and empty is about right. Not perfect but very usable. With the sender out of the tank but wired to the gage you can make your adjustments to get it to work with your gage.

Mark

I have fought the problem of trying to match a different sender value to gauge several times without much if any succcess. The only ways I know to change it is to put resistance in series or parallel with the sender. Neither works well. The series resistance moves the needle up or down on the gauge face depending on if it 0-? or ?-0 ohms. Putting resistance in parallel puts in why too much non linearity.
Another way I have not tried, but may work, is to put some resistance in parallel with one or both coils in the gauge itself. Your nephew can 'breadboard' this quite easily and see if it works.
If you have a fresh tank then, as written above, the best idea might be to modify your tank to fit a correct ohm sender. Hot rodder's do it all the time.
Please understand, I made my living doing instrumentation. Gauges that read incorrectly are of no use to me. Others find that close is good enough, just not me. I try to live with the motto, "It will be just fine as long as it's perfect".

Agree with beltfed. We had a saying at the Aerospace company I worked. Someone would say "If it's ain't right, what is it?"....we all answer in unison....WRONG!
In our world and beltfed's world there was no in-between. Too much at stake. Not just running out of gas in a truck.
I also have never had much success in trying to fool a sender and gauge with discrete components. The result is about the same as a dip stick. Life is more pleasant if you just use a 30 Ohm sender for a 30 Ohm gauge. You will have more friends. Gophers will leave your garden alone. Your tires will last longer.

Thanks guys. I hate the term "its good enough". Its either good or its not!
Beltfed, my nephew is talking the same language as you as to what we can do. It will be at least a week before we can get bck to it. (building his son a house) and I also want to talk to my gauge resto guy who has been doing this for probably 40 years. I'll hopefully see him before the week is out.
I'll keep you guys posted so don't give up.

As "suitcase" says on the Jesse Stone movie series "the information is out their, we just have to let it in". Love it!!

Achipmunk, You just opened a new can of worms. If you have a gauge restore guy hanging around then just about anything is possible. He should be able to build your gauge to read any sender's output. I converted my originals to volts instead of amps, bulb type oil pressure and heat to electric, and added damping to the gas gauge as the tank is not baffled. All look as original (well, the voltmeter is a little different) as the day it left the factory. All it takes is the will and the bucks.