Bit of an on going project this. Have been playing with using veg-oil as fuel for awhile and will shortly do a full conversion over to a twin tank system - 6 port fuel change over valve - decent heat exchanger.

There are plenty of different options for installing a twin tank: Under wheel arch, genuine CSW aux tank, custom tank mounted in loadbay etc but I want to exploit the 110's capability of using an under seat tank.
If I didn't have 2nd row set of door this would be easy, fit a fuel tank off a landrover 90 and drill hole for the filler in the side and pump it in. Unfortunately the doors and footwell get in way of that plan.
Next idea was to obtain a underseat tank form a military series landrover, or lightweight or series 1. These have the benefit of being filled from the top after flipping the seat base. So I purchased a suitable tank... but whoever said they fit a 110 was a f'ing liar who never tried it or they slung the tank so low it would be lost on first offroad trip. A good 5 inches too long.
Not wanting to attempt a re-fab of the series tank (cut n shut!) so I took another look at the 90 option. Instead of messing with measurement - it was easier to obtain and tank and suck and see what would be need to be done to fit.

First of all the cubby box under driver seat needs removing by drilling out the rivets. Contrary to popular belief this part of seat box is steel not alloy. With it removed the drive side of seat box is pretty weak. So out with disc cutter to remove the top portion of the removed 'cubby box'. This is then riveted back in place to strengthen the seat box back up again.
Next offering up the 90's tank the first thing to make contact was the filler breather pipe and the filler neck. So these had to go...

Cut off and a blanking plate welded over. To ensure of no leaks due to dodgy welds I coated the area with glass fibre resin. With that done the tank could be raised up to where it supposed to be on par with the 90's installation.
Next I need to install a new under seat filler. I had the option of removing the big one from the Series fuel tank or using the side filler from the 90. No wanting to ruin the series tank I opted to butcher the 90 filler which I also got the the scrap yard at same time as the tank.
So slice and dice with the grinder gave me a nice short filler neck. Out with the jigsaw to give me a hole in the tank. Out with the welder and resin to finish...


That about it for the mods on the tank itself, just need a coat of paint. Fits in the hole nice...

Next job will be to bracket it so it stays in that position without be having the trolley jack holding it there :D

UPDATE: Front tank bracket made from the original 90's bracket, reversed the mounting points so it fits the 110's trailing arm bracket. The rear just need extending with longer bolts to lock it in position and picking up on exsisting holes in the outrigger (drilled out to accept 10mm bolts).
Tank painted, waxoyled and fitted. Fuel lines fitted and run up into the engine bay ready for next stage.