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MG Midget and Sprite Technical - Fuel tank sender access modification

I am considering whether to cut an access hole in the boot floor to give access to the fuel tank sender unit on my Frog project. I know this is something that some have done but I am not over very confident over the idea. Shall I shan't I?
GuyW

I wouldn't bother! Just imagine crawling into the boot in the dark to remove all the screws, the stink of petrol and then getting it all sealed again afterwards! Its easier to drop the tank. I have only ever removed mine once in 40 years when the car was restored and a new tank fitted!
Bob Beaumont

I'm with Bob on this. My frog has been in the family for 50 years (mine for 45) and in that time I've had the tank out once to replace the the seal for the sending unit. Cutting a hole and making a cover is just a bunch of extra work for something that you'll probably never need (unless you live another 50 years).
Martin

No, seems a lot of work for not much chance of seeing a benefit. If the gauge goes u/s you can always use a plastic (flexible) dipstick.
davidsmith

Until I took Cherry off the road, I'd been zeroing the trip at each fill-up for years. She'll get a new sender this time, and fingers crossed.

I wouldn't cut a hole.
Nick and Cherry Scoop

OK, Thanks all!
That's 4 votes against, all from respected folk here so that settles it conclusively for me.

Ta!
GuyW

Got our midget back in 1989. Dropped tank very easily only the one time since then. Sounds like more work to chop a hole in the floor with all the problems associated with it as mentioned.

Clare
Clare Ravenwood

I hear you guy

Im concidering doing the same with a6 inch hole saw ... then add a little extra sheet metal and pop rivit the hole back togather.. ithink that would be far easier then dropping the tank and all that mess esp with the pan hard rod in the way..

But im still on the fence

Have you made sure its not just a bad ground?
Prop and the

Hi Prop. Where have you been? You've been missed!
No ground problem yet ;-) It's on my Frog project so there is nothing fitted to the bare and as yet unpainted shell. Anyway, l have decided against cutting a hole in the floor. Dropping a tank is pretty easy anyway.

What l will do when the time comes is solder on some extended fly leads for earth and live for the tank sender, so at least l can check supply and earth without removing the tank.
GuyW

I did this on an Austin 1100 many years ago and used a square rubber bung, the one used on Midgets where the clutch bleed screw access hole is located.

In all the years I owned the car I never had to remove the bung!!!!!

Rob
MG Moneypit

Obviously worked well Rob. A good solution to make sure your tank sender never failed!
GuyW

Talking of senders, I have the original Frog one, which works electrically (and hadn't been touched in 30 odd years showing they can last) except the metal float had rusted away. I could buy the replacement senderfrom Moss for £40+ but had a go at making a new float from tin plate. It floats in water but I may have used too much solder as they need to be light so might have another go. I could use a generic plastic float but it would need sealing to the metal arm with something petrol resistant. Just another side project Guy.

Bill
W Bretherton

Sorry guy

Im in internet waste land basically a place that time earsed off the map long ago ... WAY out in the stix. Working on a job

Maybe in a week of so ill be back where rhey serve coke a cola

Prop
Prop and the

You wouldn't happen to be in Guantanamo Bay undercover would you Prop?

Cheers,
Clare
Clare Ravenwood

Clare, why is it that Guantanamo Bay sounds like such a pleasant summer seaside resort whilst E-Bay sounds like the name of a Gulag in Northern Siberia?

Anyway if Prop is having difficulty with getting an internet signal I think he must be working underground. Mount Weather perhaps, that sounds like pleasant resort!
GuyW

Bill,
Inspired by your mini-project with the fuel sender I thought I would search through my boxes of parts and see if I could find mine. Sure enough it surfaced amongst random electrical bits and bobs. It appears complete with an intact tinplate float.

Using a digital meter the resistance varies between 5 ohms and around 80 ohms as I move the float through its full range, though I suspect that when it is installed the range of movement will be limited below that range. I expected greater resistance figures. How does that compare with yours?

GuyW

Clair,

Id love to go to cuba and guantomino i understwnd is really nice ... once you see past the prison and t terrorist living there ... its almost empty like 20 left but donald was talking about refilling it agian with future muslim as a torture center for muslims

Will see... frankly its time to shut it down YUGE waste of money for some elderly geratrics old men thats going on 17 18 years they have been there

At this point the old men of teror my have legal rights to squatting and the bay is theres... but they will be there at least 4 more years ...

for $3 billion a monthy you would think there are better solutions then warehousing these 20 or so elderly old guys

Yet trump wants to end meals on wheels to elderly people in the usa which is fairly cheap for mega times cheaper then keeping cuba open

Prop
Prop and the

Guy
I get similar resistance figures I.e. 3 to 82 ohms and I think that is ok. I recall testing mine with the gauge and it worked properly. The older gauge uses a "bridge" arrangement whereby the sender resistance forms one leg of the circuit. This compensates for voltage variations as the Frogeye lacks a voltage stabiliser. If you attempt to test the gauge directly from 12v it won't work properly, it has to be connected correctly via the sender (or equivalent resistance) using both terminals and ground.
Bill
W Bretherton

Guy
This is an excellent article on the older gauge from mga guru. The page I've linked to shows the bridge circuit. Previous pages cover calibration of the gauge internally although I haven't tried this as it is somewhat delicate. The sender resistance range given compares with our readings. I'm assuming the Frogeye gauge is the same or close enough.

http://www.mgaguru.com/mgtech/electric/fg_05.htm
W Bretherton

Thanks Bill,
You have me at a disadvantage here as electrics is something I have only a vague comprehension of. I have saved the pages and will go back too it at some later date but even the word Bridge in your message distracts me to thinking of footpath structures over the Langdale Beck, making a relevance to fuel gauges seem a bit obscure!
GuyW

Basically, a bridge circuit can be used to compensate for external voltage variations so that it stays balanced or stable. But maybe you're still drawn to Langdale Beck and that isn't a bad place to be!
W Bretherton

This thread was discussed between 08/03/2017 and 20/03/2017

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