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MG Midget and Sprite Technical - Petrol tanks. Who from? Who to avoid?

Pretty sure I need a new petrol tank. Been leaking from the somewhwere on top whenever I fill it up. As the tank is at least 30 years old, I'm assuming it's pin-holed. --- But subject to me dropping it to confirm that.

On that basis, where is the best place to get the tank. Anywhere to avoid?

And why would mgoc say this about the sender unit float arm for the pre 72 tank supply.



"21 - Petrol tank- midget > 72 NRP9Z
Up to Chassis No G-AN5105500Tank capacity = 5.83 imperial gallons or 25.5 Litres.

******Depending on year it may be necessary to bend the sender float arm to compensate for reduced capacity."******

https://www.mgocspares.co.uk/acatalog/info_9126W_NRP9Z.html

Ta' in anticipation.



anamnesis

******Depending on year it may be necessary to bend the sender float arm to compensate for reduced capacity."******

This came about because of American legislation requiring a device to mitigate against fuel being pushed out of tank breathers after filling. The environmentalists were upset about it whereas in Blighty nobody apparently GAS.
After filling the tank to the neck on a hot day for example a combination of thermal expansion and vapour pressure can push fuel out of the breather, so a device was invented and fitted which was simple and effective. It is in effect an inverted bowl inside the tank from which air can escape but only slowly. So after filling the tank the air gradually bleeds from the device and lowers the level in the tank.
It's the root of the rumour that US spec tanks are smaller- they're not, they just seem to be because they will initially accept less fuel because of the anti flood device. Otherwise the tanks are exactly the same. If you wait ten minutes after filling a US spec tank you can squeeze in the missing gallon, once the device has bled the air off.
So there was an apparent difference in the "full" level between the two types of tank, after venting.

Sorry if that's a bit long winded, but that's one explanation and what they're talking about when they say reduced capacity.

Sorry I can't help regarding replacement tanks though. I expect someone can.
Cheers.

Edit: you could always try Prop's solution with a 10 litre Jerry can behind the passenger seat!!!!
Greybeard

Hi,
I think this question is purely about UK spec tanks? In which case the capacity was simply increased by enlarging the tank from approx 6 gallons to 7 gallons at some point in 1972.

I think the MGOC comment is saying they no longer sell the specific pre 1972 sender unit but you can improve its accuracy by bending the float arm in some unquantified way.

Clearly it would be better if they simply sold the correctly callibrated pre-1972 sender, but if I was in this position I'd buy the later 7 gallon tank & matching sender.
Chris
C Armitage

Another level of detail to Greybeard's treatise is that US gallons are smaller so you get more of them in the same size tank!

Some years ago on another forum someone reported ordering a tank from USA and getting it shipped back at great expense, only to find that it was exactly the same as a UL spec tank!
GuyW

ETA: sorry I started my post an hour ago.

Because that tank goes on the post '72 1275s too which had 7 gal tanks, in fact the early ones were called 6 gal but whether they held 27.27 litres or 25.5 litres I don't know.

In the Archives are details of the tank MGOC supply, IIRC Canadian manufacture, ten year something or other, I forget, IIRC thread about if the tank needs paint (or was that in MGB section) anyway it doesn't and would be a PITA to do anyway.

I was disappointed to find my old tank that I replaced was already the Canadian one and that the difference was the old one had embossed(?) lettering with make and model but new one was just a printed label.
Nigel Atkins

Anam

No recommendations unfortunately, but I wonder if they are all universally average:

http://www.leacyclassics.com/parts/austin-healey/healey-sprite/fuel-system/nrp9z.html (cannot quite read the maker)

https://mgbhive.co.uk/product/1-nrp9z-midget-petrol-fuel-tank-up-to-1972-early-screw-type/ (Looks like made in Canada and not sure what chat on these on the USA based ‘MG Experince’ forum)

Also pics on website may not be what is supplied.

If you old tank has any lige left, I wonder if anyone near you can repair it. Although if multiple pinholes suggests end of life.

Cheers
Mike
M Wood

The Leacy one *looks* like it might be the same as some on ebay, made by Specta Premium of Canada - but that's not the name I remember (I think?).

I found a leaflet for the MGOC tank manufacturer I have fitted and thought I'd posted on here but can't find it now.

https://www.spectrapremium.com/en/oem/automotive
Nigel Atkins

And once again my memory is wrong, comes with the lock ring (not screw fit) and seal, 7 gal (US!) 27.0 (wot?) liter.

https://ecat.spectrapremium.com/products/RO9B

https://www.ebay.co.uk/itm/253567276471


Nigel Atkins

The one I bought for my '60 Sprite was made in Canada, though I cannot remember the brand. I went for a late style tank to get the extra capacity, though don't know if it has the air pocket thing in it. Not correct for a Frogeye, I know (should have an integral filler pipe) but still fits same as the later cars.

Of course I am not ACTUALLY recommending it, although it was well made (unpainted) with machine welded seams. But from that other thread of mine you will know I had, briefly, a problem with it leaking from the top, possibly being overfilled or a fault with the sender seal. Maybe that is the same fuel issue😁 with yours Anam?
GuyW

Ok, thanks all.

Very interesting stuff about that us device Greybeard. Not heard that before. But 6 imperial gal's is all I need anyway, esp' these days where I rarely if ever need to do more than 200 miles in a single trip.

Pretty sure I have the screwed sender. Yep I read your thread Guy. I'm wondering if I'll be lucky and find all it needs is a new gasket. I hope to drop the tank tomorrow or Sunday, so I'll know soon enough.

anamnesis

MGOC one is 5.83 gal if that, I don't think I get 6 gal (27.27l) in mine and I often literally fill to the back of the petrol cap (the sender must take up a lot of space).
Nigel Atkins

I'm forever blowing bubbles---







anamnesis

I need a new gasket.

I'm almost disappointed. Ha ha.


anamnesis

Slosh tank Sealant will reseal a leaky tank but be careful. I used it on my 1953 MG TF and sealed all the outlets with screwed plugs. Problem was when the sealant had set I couldn't budge them and had to use heat.

Jan T
J Targosz

I'll buy a new gasket. This one lasted long enough. I can't remember what gasket go was used but that stuff you mention sound like it will do the trick.
anamnesis

Some tanks have an internal gauze filter on the outlet pipe which can get blocked with those sloshy sealers.
GuyW

Ah right. The clue is in the name. I thought slosh was just a brand not a method. I don't need that as the tank luckily turns out after 30 years, not to be leaking.

Given this is a fibre/card type gasket (for the sender unit), what's the current best sealer to use? Or none?

I have no record of me fiddling with it since buying the tank. So I have no idea what sealer I used, if any.
anamnesis

I assembled with a smear of Hylomar on the new gasket. No leaks since 2009!
Bob Beaumont

Ok thanks.

Could be that I used hylomar at the time, as there is a trace of blue colour on the old gasket. So that's what it'll be.
anamnesis

There's a stroke of luck.

I was looking for a gasket on ebay and can only find cork ones, which I don't like. So figuring I'll make my own I looked at petrol resistant gasket material.

Flexoid comes up. And I'd forgotten I already have that stuff in varoius thicknesses.

Saves me a few quid too. 😊

https://www.stephensgaskets.co.uk/flexoid-gasket-paper#:~:text=Flexoid%20gaskets%20are%20made%20from,oil%2C%20water%20and%20other%20fuels.
anamnesis

I've used a cork one from Moss in the rebuild. No gasket cement, I assumed cork would squash up and seal. However they're easily damaged and I now have to fit a new one after my disintegrating fuel cap fiasco.
Bill Bretherton

Yep that's why I don't want cork there. Too thin and fragile. Ok on the rocker cover because it's thicker.
anamnesis

Arend Stolte (a point stolte at quicknet point nl) does fabricate and sell E5 and E10 resistant fuel sender gaskets.



flip
Flip Brühl

I have just fitted one of the corrosion resistant Canadian tanks from MGOC to my Mk1 Midget, having also suffered pinholing around the filler neck area (6 found so far) on my original tank.

The new tank did not have the drain plug at the bottom, but did come supplied with a new cork seal. I gave it a coat of rustoleum then sprayed over with underseal. I used (sparingly) some Loctite flange sealant on the sender unit cork seal.

No issues with alignment on fitting, no need to bend the float wire.

Job time, @ 1 hour.
T Carter

This thread was discussed between 11/06/2021 and 26/06/2021

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