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MG Midget and Sprite Technical - New alloy Tank Arie?

Found the problem with fueling my car and the tank pick up and filter are getting blocked.

So no is the time to fit a new tank.

I am doing an engineering drawing to design and make an higher capacity ally tank and wanted to know how deep the Frontline tank had been made?

Arie I think has one mounted on his car so could you measure it please

Robert (Bob) Midget Turbo

Glad you've found the issue Bob!

Make 2 tanks when you get around to it ;)

Steve
Steve H K-ser

dohhh

Only now i rember the B with the bashed in fuel tank and strange cutting out symptoms.

Sorry i did not remember/mentioned this earlyer.

Are you making cad drawings?
Otherwise i could do them if you send me scetches.
Onno Könemann

Onno I have measured up the requirements but have not access to CAD at the moment
Are you offering to do a CAD drawing for me?
Robert (Bob) Midget Turbo

I've just asked Ben at http://www.bafabrications.co.uk to make up an alloy tank for my Sprite K Series project. I gave him a word doc drawn from lines etc, plus an isometric sketch. He's a very approachable guy and price seems reasonable.
Cheers Karl
K W Seddon

If your doing a tank from scratch... what would be cool would be to take it a step further and make it as a fuel cell... with the honeycomb baffles


in for a penny in for a pound.

Prop
Prop

Karl
I do have someone prepared to fabricate a tank but could change if there is a better solution. Could I have a copy of your drawings to see if you are making one the same as I have thought about?
Bob Turbo Midget England

Karl
I do have someone prepared to fabricate a tank but could change if there is a better solution. Could I have a copy of your drawings to see if you are making one the same as I have thought about?
rjwelchmidgetataol.com
Bob Turbo Midget England

Yes Bob i might be able to fit some tank drawing in to my routine.
Just mail me the sketches.
Onno Könemann

how about building in a swirl pot!!
Mick struggling with the wiring

Bob(R), ill mesure the hight tonight.

"how about building in a swirl pot!!"

Frontline did but it wasnt good enough to keep suplying fuel when doing fast corners.
Mine is a Frontline tank but also has an external swirlpot added.

From what ive understand frontline doesnt do new aloy tanks anymore, anybody can confirm that?



Arie de Best

Thanks Arie, need to consider the swirl pot to understand what would be best

Frontline as I understand no longer make an ally fuel tank.

I will see what Karl comes up with and let anyone know if they would like to order a tank at the same time. The one I want will be deeper and will be extended towards the rear where the silencer used to sit acroos the rear of the car. This should increase the capacity significantly which I think the frontline tank also did!
Bob Turbo Midget England

I think this is a clever means of making a swirl pot. I've not tried it, but the logic seems sound:

http://www.bcbroncos.com/store/product_info.php?cPath=131_108&products_id=1355
Trevor Jessie

Hi Bob - I'm having problems uploading picture, so I'll have to post diagram via my work computer tomorrow. As you will see I've copied the bottom tank size straight from my existing (early type) tank. I believe the later tanks are slightly deeper, but I'm lowering my car so didn't want to increase depth below the boot floor. Also didn't want to increase the size towards the rear valance, as I intend having a twin box exhaust. I'm increasing capacity to approx 9 gals by bringing part of the tank up through the boot floor (approx 200 wide x 320 deep). I'm using a Webcon fuel pump/filter/swirl pot set up. This should be OK, but my K series will be knocking out 190 bhp so I may also have to fit an external booster pump. Filler is also going in a different position, similar to photo attached (photo's not of my car). Cheers, Karl


K W Seddon

Tanks details attached:


K W Seddon

Got all that stufF Karl, thanks very much.
The tank design is not what I was looking for because I want to keep the boot space available and simply need a bigger tank. However I do like the fuel pump. :)

Arie please can you measure the frontline height?
Robert (Bob) Midget Turbo

Done a design for my tank on Powerpoint and thinking about fabricating it myself. Just wondering what thickness ally would be suitable?
Robert (Bob) Midget Turbo

If you are going for alloy don't go making it three times thicker as all the effort to save weight will be wasted!

I think a good welder can generally TIG weld 2 mm alu alloy reasonably happily, whereas with steel you could come down to something like 0.7 mm.

Malcolm
M Le Chevalier

Steve do you want considering for one of these bigger tanks?
Robert (Bob) Midget Turbo

If it includes a swirl pot and the price is right, send me an email please Bob, must be cheaper for 3!
Rob Newt

Rob the "swirl pot" I have designed is a fuel rail below the tank that will/ought to be full of fuel all the time see diagram

I have asked for a price for the tank to be made in alloy/stainles or simple steel


Robert (Bob) Midget Turbo

top view


Robert (Bob) Midget Turbo

Rob,

I'm up for one of those!

The capacity is the main thing, if the swirl pot theory works too then bonus. I need a swirl pot for the K series anyway. Give us a shout off here or I'll see you friday at the H&J?

Steve
Steve H K-ser

Hi Steve

Yep the "swirl pot" is ok maybe? I would like to see other designs?

as stated I am awaiting a price in different materials but tomorrow I am discussing it with someone local to me for fabrication in alloy so hopefully that will be a good price. The cost of an alloy unit is in the welding and this tank design unfortunately has a good few inches of weld!

If not before will see you Friday!
Robert (Bob) Midget Turbo

Robert,

I was wondering why you specified NPT, I would have thought BSP would have made more sense in the UK.
David Billington

Bob-
I had described the Mazda "swirl pot" in your earlier fuel problem thread, much better I think. My cars are 323 90-94, don't know how common the design is, but it is brilliant. If you can't find it I'll try again.

The design you propose will run out of fuel if low, on an upgrade or longish turn. It will also gather all water and try to feed it to your engine, and exposed fuel takeoffs below fuel level are very vulnerable - not good.

FRM
FR Millmore

Bob,

Sounds good, see you Friday.

Steve
Steve H K-ser

FRM

You will need to describe it again mate cos I didn't see it?

Anyway I think water in fuel is a thing of the past, not seen evidence of that for many years? But I do take the point that if any water got into the fuel it would get into the system, but surely that would be the case with any fuel delivery that did not have an unused reservoir of fuel/water at the lowest point in the tank?

On the same subject if this tank allowed the engine to run short of fuel if the tank were almost empty and driving up a steep gradient then what system would actually overcome such a situation?
Robert (Bob) Midget Turbo

Sorry David you are correct being a Midget tank I ought to make the connections BSP so consider it done. :)
Robert (Bob) Midget Turbo

OK, Mazda use an in tank pump, but it works with an external pump too, just put the pickup in the described contraption.

They have a closed bottom rectangular box, about 5"x8" x 4-5" deep, not quite reaching the tank top. This is located near the rear center of the tank, long axis across the car. There is a 5/8" diameter tube that enters the pickup box at the RH side of the RH rear corner, which then goes around the back outside of the box to the LH front corner, where it is open for fuel pickup. The open end and the bottom of the box is about 1/8" off the bottom of the tank, so most water won't run in the tube. Remember that condensation causes water in tanks - I always find a bit, but it lays on the bottom.

Fuel runs through the tube into the box, but cornering or gradients won't make it run out because it always has to change direction 180 degrees to get out. The pump is in the box, pulling from the center through a plastic screen filter, and return fuel from the engine also dumps in the box, so anything you don't burn is immediately available to the pump.

If you draw a picture from above following this description, you should be able to see why it works.

The fuel level indicator is fixed to the pump bracket, but the float is outside the box, so level shown varies with cornering and the like.

The whole apparatus, except the box which is welded in the tank, is attached to a 7-8" plate that bolts on the tank top, and Mazda kindly put a matching access plate under the rear seat so you don't have to remove the tank to fix it. All piping and wires go in the plate top. (I cut a similar hole in the bed of my Dodge truck when the pipes rusted out, strongly recommend such access ports!)

I've had it stumble only on very long uphill sweeping turns (3 miles) at very high speed (95+mph) with a nearly empty (less than 1 gallon usable) tank.

If this isn't clear, I will try to draw it and take a picture of the drawing, but that's hard!

FRM
FR Millmore

If water is condensing in the tank it will inevitably fill to more than 1/8th of an inch in the bottom of the tank so how is this dealt with?

The only benefit of that as I see it is the fuel return entering the swirl pot, that would be a good thing.

Now I am wondering what would be the case if I made my fuel return pump into the fuel channel?
Robert (Bob) Midget Turbo

OK

My local fabricator (who makes racing tanks filled with foam etc.) is willing to make the tamk. He has advised a couple of changes that I will go with. The top will be flush with the tank and the mountings will be angle welded to the side. The swirl pot will be circular at the bottom of the tank (like the original rail)

His price will be £175/£200

Just waiting for the comparrison tomorrow.

What do you think Steve?
Robert (Bob) Midget Turbo

Bob, thats not bad, is that a quote for 2 or 3 tanks?

Rob Newt, if you are interested, my parents live Halesowen way which at a guess isn't too far from yourself? I could get the tank off Bob and meet you that way on a visit to the parents perhaps?

Steve
Steve H K-ser

Hi Bob(R), sorry for late reply, ive been buisy with non-car-related stuff.

heigth of Frontline-tank is 15cm at the front and 4cm at the rear.
Seen on the side the flatpart of the bottom is 30cm and the angled bottompart is 19cm.

Hopefully this is of any use to you.


Arie de Best

Hi Bob

Don't forget to post the final spec when you have it...

A
Anthony Cutler

Hi Ant the final spec is about complete.

Instead of the fuel channel, I have gone with a 3 inch circular swirl pot at the underneath of the tank nearest the axle. This is fed via holes in the floor of the tank. I had considered having a "dip" tube arrangement from top of the tank into the pot but I can not see how that differs to a connection on the side of the swirl pot? so for now the only connection on the tank top is for the early type tank sender unit that is screw fitted in the tank and not the later twist type.
Bob Turbo Midget England

"I can not see how that differs to a connection on the side of the swirl pot?"

Only diff I can think of:

It allows your external connection to be up higher to shield it from possible damage, and if there is damage/leak there will be less fuel lost.
Trevor Jessie

I'm sure I remember a follow up post to this by Bob with pictures and results of his new tank, but I can't find it. Can anyone point me in the right direction, or Bob can you give us some follow up?

Also Bob (if you're still out there, haven't seen you post much in a while) do you have an updated drawing for the design you ended up going with?

Anyone else have any input on larger than standard tanks? I've been looking into the possibility of having a couple of larger tanks made up for myself and a friend. I would contact some of those listed in this thread, but shipping from the UK for a couple of fuel tanks would probably add up, not to mention the difficulty in after sales service if something wasn't right...

I wondered about also extending the drop at the axle end (as it shouldn't compromise ground clearance closer to the axle), maybe to 8", decreasing to 7" where the rear of the original tank would be, then 5" at the rear as per Bobs design. Also, has anyone wrapped it around behind the wheel for some additional capacity?

Why a larger tank? Well my car gets reasonably poor fuel economy and is picky about what fuel it uses, and there can be reasonable distances between fuel stops in Aus even without looking for specific fuels. So it will make it less stressful holding out to find appropriate fuelling locations. And the other car interested has a ported 13b rotary engine in it, so gets abysmal fuel economy and is lucky to get 100km to a tank (original 6 UK Gallon) when driven hard! Even driven softly it struggles to make 150km.
Andrew F

Anyone?
Andrew F

Sorry Andrew, I have no drawings or sizes of the Frontline tank.
I can messure outside demensions hwen I get my car back?
Arie de Best

Hey andrew,

Good news... or used to be

If you go to ebay, they have aftermarket tanks and they are made bigger in volume then the factory....I know mine is bigger in volume... I want to say its 7.5 usa gal. Instead of the 5 to 5.5 factory gal.

Really that about the max for plug and play without modification the tank was just deeper...but it still uses the exact same foot print...

Another alt if you want a bigger tank is a fuel cell that fits into the boot....there plastic and have a honeycomb mesh inside...its for racing, but there cheap.and common on ebay

Im not sure there is that much advantage to a bigger fuel tank... in my region of the world we.have a gas station every 5-10 miles..and with an extra 2 gallon capcity you talking an extra 60-80 miles of distance

If you need to replace the tank, then yes go for the bigger tank, but if your just replacing the tank for a bigger tank...then id just buy a small 3 gallon tank and mount it in the out of the way courner of the boot above the fuel pump with a little electic valve switch for duel tanks and a switch in the dash... its easy, fast and cheap...and you got 8 gallons with no body mods just vent the 3 gallon plastic carry tank thur the cars gas fill up pipe

It may not be everbodys cup of tea, you may have to pull it and reinstall at MOT...

But sure beats a one off custom made tank and then the hassle of installing it

Prop
Prop and the Blackhole Midget

Prop,

When I had a look a week or so ago I couldn't find any larger tanks listed on Ebay? Do you have a link perhaps? Also, if you mean a tank that is made to the larger size of the later standard tank, then I believe the difference is 7 UK gallons (31.8L) compared to 6 (27.3L). For me, the difference when driven hard would be less than 40km in range, for my mate with the rotary conversion it would be less than 20km additional range! Not worth the hassle. From reading I believe the Frontline tank was 9.5 UK gallons (43.2L) which is a much more useful increase (130km+ for me, ~65km for my mate - again driving hard, greater increases if taking it easy), and to be honest I was hoping for a bit more even than that. I'm glad you have fuel every 5-10miles (8-16km), over here it is very common if you get off the beaten path to travel 100km (60miles) or more without a petrol station, and if your car is picky about what fuel is used (as mine is) then it can be a lot more than that.

Not really interested in having a fuel tank in my boot space either, and I don't think it would be easier to hook up an aux tank (it's not hard to drop and replace the tank!), and definitely not legal over here, but thanks for the thoughts.

Arie,

Yes, some measurements would be a great help if it's not too much hassle, thanks!
Andrew F

This thread was discussed between 20/03/2011 and 24/07/2013

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