I have just spent about 1 day taking the rust off a pair of petrol tanks from 4688R, cleaning out the sh1t that was inside the tanks, unclogging the two fuel pipes, and replacing the fuel tank gauge, then spraying with primer ready for the gloss black top coat.
When de-rusting the two tops, lots of holes appeared and they looked like sieves. I intend to re-face the tops with fibre glass mat, as the tops only have to contain petrol vapour, and stop rainwater getting in. Does anyone know if petrol vapour will affect the fibreglass resin?
The tanks were lined with earth. Quite what had been in there, I have no idea. Moles, chipmunks, mud dawbers? Boiling water, a lot of sloshing around, and after about 6 flush throughs, the water came out perfectly clean, and all the sh1t seems to have been cleared out.
As for the fuel pipes, both were blocked solid with sh1t. The only way I could clear them was to use the wire from the heater controls, a pair of mole grips, and a hammer. I gently tapped the wire down the tube, about 10mm at a time, gripping with the mole grips and tapping the mole grips with a hammer. 1 pipe cleared quite quickly, but the other pipe needed a bit of straightening to the 90'bend, then clearing, then careful bending back to 90'. I then used a pressure airline, then tested the outflow by putting a bucketful of water in, and seeing how quickly it came out. All appeared fine, so the pipes, which go about 6" into the tank with a 10 degree kink in them, appear clear.
As for the fuel gauge sensor, I bought an MGB one for about £20, but the arm was much shorter. Unlike my previous post, you cannot change the complete arms over, as the copper arm inside which slides over the wound wire to vary the resistance, is different. So I cut the Lotus float wire arm, attached it to the MGB arm with lots of lockwire, made sure the float was in the same plane as the original, and refitted the mechanism in the tank. There are three nibs which the locking ring mechanism grips on. One of the nibs kept missing the ring when the ring was tightened, so I increased the dent of the nib with a chisel and hammer, and the ring tightened up to its original position. The MGB float came with a new rubber O ring, so it should not leak when assembled.
I also had to fit new drain plugs, as the originals had gone AWOL. 1/2" UNF bolts with lock washers seem to plug the hole nicely.
When fibreglassing the tops of the tanks, I put about 3" of water in the bottom, as the resin drips through the holes, and the water prevents the resin sticking to the inside of the tank or plugging the outlet pipe.
Next on the list for next Saturday, tap the holes in the R&D Stromberg head for the inlet manifold plates. I have also started on the manifold to Weber plate, but cutting the correct size holes is proving a challenge. A hole cutter does not like cutting aluminium, it takes ages. Photos to follow soon.
Alex in Norfolk.
