The job of fitting the fuel tank and the fuel filler cap really have to go hand in hand. When we were fitting the rollbar we had provisionally fitted the fuel tank in position and decided to cut the hole for the neck of the filler cap. After looking at it for a few weeks we weren’t 100% happy with the position due to it being a little off set from the centre of the roll bar, so we decided to try to adjust the tank and cap position a little to get it more central. The build manual gives a good description about how to do this. In our case though, as we had already made the provisional hole, it meant fitting the tank in position again, shifting it across to the nearside as much as possible. We could then see how much we needed to move the hole which we had to extend slightly with the dremel. With a little hindsight we wished we hadn’t been as hasty drilling the hole originally as we could have made a neater job of this if we’d fully considered the position of the tank properly measured it, but we consoled ourselves with the thought that this hole would never been see again once everything is fitted so its not too much to worry about. We will of course tidy it up as much as possible
Once the hole was big enough it was then the case to find the correct position for the screw holes. So we fitted the filler cap to the flange in the vice as tight as possible, as it would eventually be on the car and positioned the clip and hinge of the cap so that it would sit perpendicular to the length of the car. That then gave us the position for the screw holes which we marked and drilled. Once this was done we could do the final fit together with the gasket and nuts and bolts.