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MG MGB GT V8 Factory Originals Technical - Converting Gas Tank

Hey everyone, I was wondering what was needed in order to convert the stock gas tank so that EFI can be run. Anyone done this and can let me know? Thanks.
Jarrod Hills

Use the 1965-1969 fuel tank which has the fuel feed pipe built right into the tank, then use the fuel sender from the 1977-1980B with the fuel feed pipe built into the sender. You now have a fuel feed, AND a return line without having to cut up your tank. Try to keep at least a couple gallons in the tank if you can. Sometimes it starves on prolonged, sharp cornering when the tank is almost empty.


Great answer Justin, you beat me to it!!
Larry Embrey

From previous posts & other reading, it seems that you can add an external surge tank fed by the original fuel pump then a FI pump feeds from the surge tank to the FI system. No mods to the previously suggested tank arrangement.

Another solution involves the use of a very large fuel filter to serve as a surge tank.
Jim Stuart

on My midget Turbo I removed the filler neck from the tank drilled a hole in it near the top inside the boot then welded a pipe into it with the end pointing down towords the tank 1 very easy return line with no cost and it seams to work fine
p Dorner

That's what I did too. However, I also installed a sealed surge tank in the unused battery well, used an aftermarket low pressure pump to supply the surge tank, and ran a vent line to the gas tank filler neck to return vapors to the fuel tank. Thereby preventing the very real possibility of the surge tank running dry due to excess vapors. I restricted this return line so that fluid flow is only a trickle but it vents vapors as required.

I then connected the lines for the fuel injection system to the surge tank, using a high pressure pump in the supply line, in this case one for a Ford F150 truck with dual tanks which is a frame mounted pump. This, the surge tank, and an inertia switch fit in a molded battery tub along with a 2" layer of foam for sound insulation. Line routing was tricky but eventually I got that worked out too, and the system has worked flawlessly so far. Both pumps have inlet filters btw.

Jim Blackwood

Most of the specialist hose retailers (in UK) sell a connector return fuel line into the tank. (Drill a hole and screw tight).

A large pre-(external)pump filter will act as an external surge tank.

With the right choice of FI pump - you will not need the OE (LP) pump to feed the 'surge' tank. However you may be sacrificing some of the lifespan of the FI pump.

My own (Bosch) is complaining after two years.

If you drive regularly, at speed, round long corners, you may want to think again.

Press on - 3.9 14CUX EFI MGB is phenomenal on the road. (This is the UK Bosch derivative but your own may be even better). Don't overlook the brakes or suspension.


If you wish to save money and don't mind a little extra effort you could put a return/pick up line into your sender "lid" youself. There should be room, just take care not to foul the movement of the sender float. Since you can remove the sender from the tank you don't need to worry about degassing etc, and can weld drill whatever. Try to get the pick up line next to the return.
You might want to try to improve on what I & others have done and have a hairpin loop of line extending to the bottom of the tank with some ingress holes in the lowest point , that way the return fuel is flowing directly into the pick up and should take some of the (mild) strain off the pump.
It seems easy enough & I intend to try it sometime.
Mind you if you're in a hurry (as I was when I did mine) then just going and buying a later sender (job done), is very attractive

This thread was discussed between 26/10/2003 and 30/10/2003

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