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MG Midget and Sprite Technical - Fuel tank sender - resitance range

Does anyone know what the resistance range is for the later fuel tank sender in Ohms. Thanks.
Daniel

Hi Daniel,

Good timing.

From the searching I've been doing over the last couple of days, the resistance range of the *later* ring clamp sender is ABOUT 240 ohms empty, to 20 ohms full. I say about because it seems to vary between suppliers/makers according to ---
http://www.mgb-stuff.org.uk/gauges.htm#sender

And the EARLY sender, whose resistance operates in the opposite way, that is high ohms when full, and low ohms when empty is --
Resistance range; 5 to 85 Ohms.
According to --
Original Equipment Manufacturers part as fitted to MG midget Mk1 to 3 and AH Sprite (Spriget) Mk2 to 4, 1962 to 1967, see my ebay shop for BHA4711 the sender for later cars. Can also be fitted to Austin Healey Sprite Mk1 (Frogeye). Smiths number: FT5301-06A.
https://www.ebay.com/itm/194431662185

I'm now trying to find out if I could swap the resistance coil from my early screw clamp sender, to the later ring clamp sender, such that it will work with my early gauges.


anamnesis

Found another reference.

Regarding the EARLY senders.

"Your original gauge should be a Smiths FG2530/31.
The sender unit should be 3 ohms when empty & about 85-90 ohms when full.

Regarding the LATER senders.

***Later*** sender units should be 220 ohms when empty & 20 ohms when full.

The MGAGURU.com site has some very good info, though it can take some finding!"
https://www.ahexp.com/forum/the-sprite-forum.6/fuel-sender.277788/

And ---
A recent quote from our noble friend John Twist at University Motors: "We always try to repair the original one, as the current replacements are so bad". Original units have a metal float, fine resistance wire at 0 to 70 ohms,
https://mgaguru.com/mgtech/electric/fg110.htm

Seems confirmed. Unless I can swap resistance coils, I have to change gauges or stick to the early tank fitting.


anamnesis

My measurements on original later units went 240-20.
And yep, back to front compared with earlier units. I fitted the larger later tank to my B, made the gauge read E = Enuf, F = f-all
Paul Walbran

>>made the gauge read E = Enuf, F = f-all<<
Lol!🤣

That works just fine!
Greybeard

😅. Yep that works. 😆
anamnesis

This thread was discussed between 07/10/2024 and 12/10/2024

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