Trouble Fitting a New Alloy Fuel Tank

[Gardog]

Hello all.

I am a new Lotus owner ('69 S4 Federal) and new to the forum.

I recently bought a new alloy fuel tank from one of the major parts suppliers in the UK. The tank looks fine but doesn't fit at all well.

The profile of the bottom of the tank is slightly different than the original and I can't get all three of the mounting studs to stick through the holes in the body at the same time. They seem to be in the right locations but tank bottom is high-centereing on the trunk (boot) floor. I could use longer studs and shim the bottom with foam but there would be a gap of as much as an inch between the tank and the truck floor in places.

I am also having a problem with the filler neck. The new one is in a slightly further away from the edge of the tank and protrudes at a slightly different angle making it impossible to line up the neck with the filler tube without lifting the tank further off of the truck floor.

Adding to my frustration is the fact that the fuel outlet pipe protrudes at a different angle than the original and fouls with the body. I may be able to make this work but it will depend on how the tank is positioned in its "final resting place".

I should add too that it has been an exercise in detective work to sort out the size of the fasteners needed for both the mounting studs and the sender unit. The captured nuts for mounting are imperial and the treads in the sender mounting flange are metric (3.5).

So a question for all of you more seasoned Lotus owners - Did I get a bad tank or is this another example of the charm and challenge of owning a hand-built vintage car? If the answer is the latter, then any advice on getting this thing to fit would be greatly appreciated.

Gary

[nmauduit]

do you have the original steel tank for comparison? it would be quite useful for other potential buyer to assess the non fitting risk of such a large part, esp. considering shipping costs these days...

[jimj]

Some years ago I bought an alloy tank from ebay and it didn`t fit properly. I made some rubber spacers of different thicknesses for it to sit on. You wouldn`t want to use foam which might trap water. The filler also didn`t line up so the rubber connector is distorted a bit, I had to struggle to fit that so I slid it on before I bolted the tank in.
Jim

[elanfan1]

I found locating the holes difficult to get into the right position. Locating the one under the rear bumper first seems to help. In the end I couldn't get the third one in so had enlarge the hole then refill later. Be careful before finally fixing with foam, longer suds etc - make sure you can fit the spare wheel next to the tank as it is quite critical there. No good fitting the tank only to find you can't get the spare in.

[Elanman99]

Gary, your experience is not uncommon and its not just related to fuel tanks. Some of the parts being sold by reputable companies are often quite different than the original Lotus components. They might look similar but it only takes one dimension to be a bit off to cause a problem.

As it happens I had very similar problems with an aluminium tank, I just cannot understand why the filler tube on mine is welded at an angle very different than the one on the original steel tank. The tank looks to have been made by a highly skilled person and the metalwork and welding is really first class but now its in the car, every time I open the boot all I see is a joggled line of filler tube, rubber hose and the tank inlet tube, to me its just an eyesore!

Knowing the way Lotus operated in the day, the steel tank was probably not an expensive item but it did fit! A long time ago I bought a new steel Lotus tank when mine rusted through and it was drop-in fit. I wish the same could be said for hoods, tonneau covers and radiator hoses etc.

Really it should be the responsibility of the supplier to provide goods, fit for purpose but in your case with a seller thousands of miles away it ends up that you have to go to extra trouble adapting the 'not quite right' part just to be able to use it.

I would not be too concerned about the mounting hole positions as it not difficult to drill the fibreglass so that the tank is as low as possible.

Ian

[William2]

I fitted a secondhand alloy tank to my car and had to jiggle it around a bit to fit. I had a gap of about 1/2" on the rear fastening so I packed it out with a few rubber washers. I suspect that most of these tanks won't be an exact fit.

[Gardog]

Thank you all for your thoughts and advice. I have managed to install the new tank and it looks okay. It doesn't sit as low in the trunk as the original and the filler pipe rubber hose looks untidy but I think I am good to go.

A word of advice to anyone buying a new tank - Be sure to talk to the supplier about all of the nuts, bolts and screws required. The supplier of my new tank had machined the sender flange with British Association threads. These are impossible to find around here and really should have come with the tank.

Gary

[AHM]

Sender screw threads are fairly universally 3BA.

[Gardog]

Interesting. My tank was threaded with 4BA. I guess I will lose concours points for the wrong tank and the wrong thread size.