Fuel tank sending unit

[Flat Ernie]

My apologies - I'm in a hurry & did not read every response.

I have had no issues getting two of these sending units to work well, but I will caveat that with also doing 12V conversions and using CVRs.

The stock units designed for King-Sealey WILL work with variable resistance sending units. The principle is the King-Sealy sending unit supplies full 6V through the heater wire in the gauge in a chopped manner - on-off-on-off - with the "on" duration being the variable. It is this full current which heats the bi-metallic strip in the gauge that causes the gauge to read via a small gear train (that is adjustable, BTW). A variable resistance sending unit does the same thing, but it sends less than a full 6V to the heating wire and therefore doesn't heat the bimetallic strip in the gauge as much.

There are two problems that arise - how the voltage is dropped on 12V conversions & how the sender is calibrated.

This is why I always use an solid-state CVR to drop my gauges (except '40 battery meters). You get a steady 6V to the gauge & sender. With a dropping resistor, you get something near 6V that varies with the output of the 12V alternator/generator. With a chopper (the factory '56-up 6V dropper that most folks are fond of), you also get a variable voltage to your gauge and sender.

It baffles me why anyone would use a chopper, even free from a junkyard, when the solid-state CVRs are about a dime, provide constant, reliable 6V (not variable with output of generator/alternator) output.

Adjustment is tricky. I'd like to see the aftermarket sending units have a shorter range of motion over the same resistance value. You want as long an arm as possible to accurately reflect the fuel level, yet you still want to swing the arm through it's full range of motion. With the wide arc the aftermarket senders have, you can't have a very long float arm (or you hit the top/bottom of the tank before reading full/empty).

If you can get your gauge reading well at one end, but no the other, you may be able to adjust your gauge geartrain. Go slowly here and adjust in tiny increments. I prefer my gauges to read accurately when empty rather than full.

I will adjust so my empty puts the float about 1/2" above the bottom of the tank when the gauge reads "E". I accept what I get on "F". There are ways around this, but they are mostly trial and error - playing until you get what you want/like/live with.

[badnabor]

Originally Posted by jdl

They must make the hole smaller so they can sell you a sendining unit, I bought a tank and the Ford unit is to big to enter the tank. I did make the Drake sender work o.k. but not as acurate as the Ford unit.
Measure the tank depth empty and write it down, then cut the arm as per instructions, fill it up and drive until it shows 1/2 tank then remove sender (first disconect batt) and re-measure to the gas level. if it is 1/2 of your first measurement you are good, if not you will need to bend the arm up or down to adjust. a real pain in the --- but I got mine real close. this may not work on your car, mine is a 51 with access to the sender via the trunk. if I were to do it again I would try to enlarge the opening of the tank so the Ford sender would work, but to late now.

My sentiments exactly! I just bought a tank for my "51 Victoria project and ran into the same problem. I wonder if they are wringing their hands & having an evil laugh while waiting for the sending unit order to come in after they sell you the tank?

[19Fordy]

40cpe, Rotorwrench and FlatErnie got it right. This topic has been discussed many, many times with the finding that there is no aftermarket fuel tank sending unit that will "accurately" work in conjunction with the bi-metallic heat sensitve King-Seeley gas guages. The key work is "accurately."

[merc40]

early v-8 times in may/june 2001 has a article by ellen bruckner on electric fuel sender repair. very good read. reguards dick t.

[41ford1]

I am running a resistive replacement that works with the stock gauge. When I received it from Joblot I was skeptical that it would work. Joblot sells it as a replacement style sender for 01A-9275. A bench test showed the that it does in fact work. Float arm at the bottom of its travel showed empty, half way up shoed 1/2 and the top of the travel showed full. Empty resistance is 82 ohms. Full resistance is 10 ohms.

[19Fordy]

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Holy mackeral, I stand corrected.

[Flat Ernie]

Yes, but can you translate that range of motion inside the tank. All of mine would work well on the bench, but because of the range of motion, it's hard to get them to read accurately once installed....If you shorten the arm enough for it to read full when the tank is full, you'll read empty with about a eight tank of gas left.

I suspect you can probably get it to read correctly by adjusting the gauge itself. There are tiny gears behind the paper covers that you can reach in and tweak to change the tension on the bi-metallic strip. In theory, you could fill the tank and then tweak your gauge to read full. I suspect that when you drain the tank, empty will be correct, but your float will be sitting on the bottom of the tank and you won't have any reserve - empty will be empty. I've never adjusted one this way as I prefer to have a little cushion on empty and accept that it won't ever quite read 'full'.

[early28]

My solution to the new tank and sending unit was to throw the new sending unit away, make a 3/8 inch spacer, extend the vertical drop on the original sending unit 7/16 inches (spacer and one extra gasket). It's a tight fit but the tank was not modified and all works well.
Have a good one and God Bless, Selmer

[41ford1]

Flat Ernie,
I installed it the day I tested it. That was 3 months ago. I've run 4 tank fulls of fuel though it since. It reads accurate and is consistant.

[Flat Ernie]

How empty are you getting it? I always run mine completely out of gas the first time I use it - that way I know what empty looks like on the gauge. Of course, I carry a 2.5gal gas can with me during this experiment!

I don't doubt you, just trying to get more data from you - You might've gotten lucky, or they may have changed the sender. There are, however, enough tolerance stacks in the system to make it all work out perfectly.

[41ford1]

Ran it down to E once. It took 13 gallons to fill. I figured close enough with a little reserve.

[rozroost]

just installed new gas tank and sender from tanks inc.. Followedinstructions as to what length the float rod should be. 12 v with original 6 v guages.Put 5 gals. in. guage reads over 1/2, went and filled tank, it took 9.2 gals. and now reads way passed full. It looks like this replica tank holds 14 gals. I don't know how many gals. the hold tank held. This is not the shape as original- is not as deep. I am hopeing wireing in some resistance will correct without having to keep bending the float rod. Will be working on this coming sat. Any advice appreciated, I wiil keep you posted. Thanks Rozroost

[Flat Ernie]

You have to keep adjusting the float rod...it may require shortening as well

[Fugal 41]

1941 Ford conv. coupe, stock, fuel sender pain to set. Solved the problem with a VDO Reed Switch Fuel Sender - 150mm - 240-33 Ohm # 226-615. 150mm is the length for a 6.5" fuel tank. 12 volt gauge. No adjustments or fitting. Look it up on line. Mine came from Ebay. Good Luck, See ya