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MG MGB GT V8 Factory Originals Technical - Road legal fuel tanks

Righto, I have a 1971 MGB GT V8. I'm looking into fitting EFI, and upgrading the original fuel tank in the process. I would like to fit a boot-mounted racing fuel cell, but I'm unsure of the legalities of it r.e. MOT test as the car must remain road legal.

I was under the impression a car would not be road legal if the tank is not sealed off from the rest of the cockpit?

However, even in original form the GT has its fuel pipe exposed (albeit under the wooden boot floor thing (which I don't have BTW)).

Ideally I would like to fit a 40-50 litre low profile tank with a small sump, dual pick-ups, return and/or vent pipe, and also a VDU sender unit.

N.B. I currently run the fuel line inside the car and it passed its last MOT no probs.

Any thoughts?

OT Hayter

Contact who ever is the legal body for MOT and ask!
Peter Thomas

I'm surprised to find that running the fuel line inside the cab is legal. I think you'll find that running a high pressure line for the EFI certainly won't be ! If you look at the Street Machine scene, they have to mount all their high pressure gauges outside the cab on the front valance & read them through the windscreen. Barrie E
Barrie Egerton

Hi,an MOT tester is not obliged or allowed to remove anything to make his inspection.So cover your fuel cell with a light alloy sheet secured with screws .A sympathetic tester can then legitimately say he doesn't know what is there.Even moreso if the original tank is in place for the test.This does not answer your question but perhaps offers a solution. regards Peter
Peter Jones

cheers guys.

Peter Thomas, I came on here to ask before I went to an MOT tester, assuming that someone might know the legalities of it. . .

Currently the fuel line is low pressure for the carbs, but I am planning on fitting EFI soon, and yeah I know the fuel line ahs to go on the outside to be road legal, I was just concerned about the tank.

Peter Jone - now that's not a bad idea, I had planned on sealing it in somehow anyway for cosmetic purposes. I'm gonna be chopping the rear around anyway for my planned suspension mods so I may as well lower the floor while I'm at it. Will get me thinking cap on.

OT Hayter

No offence intended but my reply was written in a rush so breveity was the key point.

What I meant was this: Since this is essentially a legal and safety question and since you and / or someone you care about is going to be in the car on the motorway at 70mph , I would find the relevant safety authority and find out what is acceptable to them and what is not.
Since they are the ones issuing the certificate they would be in the best position to give advice.

This is too important an issue to try and get done in anything but the safest way possible.

Sorry if it came across the wrong way.

Cheers , Pete.
Peter Thomas

Why are you replacing your petrol tank? The stock one works fine for EFI.
M Mallaby

Thanks Pete, no offence taken mate! Will do some proper research first.

M Mallaby; I'm changing the tank because the old one is crappy, and I want a boot-mounted foam-filled tank as the car is going to be a track monster. I want to 4-link the rear too - which means suspension turrets are required, and binning the old tank will give more room. Also, I need a vent and return line for the tank and can't be bothered modifying the original when I can get a track-tank for about £100. This is all planned for the next 6 months too, quite a winter project!
OT Hayter

OT, you might consider this approach,

Dan Masters put this link in another thread, some really good and detailed photos.
“Ted Lathrop, of Fast cars, Inc, has just completed a 3-link installation in an MGB”

I'm about to do something similar, except the pan hard is going at the back and the coil overs (if I use these) will go onto the existing shocker mounting points at the front.

With a three link you can adjust for squat and hop by adjusting the angle of the middle link. You can’t do this with a four link. Initialy, I'm going to try about an inch down at the front. I am going to use a bolt on bracket for the top of the diff' with a row of mounting holes so I can play around with link angle, and adjust for pinion angle. Same with the top of the tunnel mounting point.
With 3 links there is a good deal less torsional, and no lateral stress. With a 4 link there must be some side to side movement of the upper arms as the car rolls in corners. With a centre link there is only torsional stress (and not as much) that is easily taken care of by the bushing.
You can compensate for drive shaft reaction, ( when the right wheel lifts a little under heavy acceleration), by offsetting the upper link a little to the right, about 3 or 4 inches ideally. The TAN of the diff’ ratio (I foggily remember) This is what they did on the early C type Jag' and what they are currently doing with the cobras. The current mustangs also use a three link but they are using a very short centrally placed upper link which is not as good.
I also intend putting in twin fuel tanks where the battery boxes currently are (like a Jag’), but haven’t looked into the details of this yet so don’t know if it is as feasible .

half as much lateral stress, I should have said.

If you are doing that much sheetmetal surgery out back, why not have a flat rear floor and mount the tank up from underneath?
You could even include an access door in the floor to get at the lines, pump and electrical as needed.

In the US, the early Mustangs 65 or 66 I believe had no separation between the tank inside the trunk and the passenger compartment. Very bad indeed.

Love to hear how you finally work it out.


Brian C.
Brian Corrigan

This thread was discussed between 18/09/2006 and 06/10/2006

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