After writing up the blog last night I realised I’d made a bit of a boo boo. I wasn’t supposed to drill the chassis till I’d done the fuel tank covers. Having said that the reason I’d ended up doing it was because the way the bulkhead panels fit together meant they only fitted in one place anyway. So I was hopeful it wouldn’t be a problem.
The fuel tank on the BDN is a bespoke item hand fabricated from aluminium and sits across the chassis floor immediately behind the bulkhead, so it’s across the bottom of the front of the engine bay, hence the covers. It’s a fairly complex arrangement, and I spent a while studying the 2D drawings as well as the 3D PDF which you can zoom and rotate. I started with the left hand tank cover, the photo to the right shows what it looks like to start with. First job was to do the main fold down the middle then work out the best way of tackling all the edges. SO far as I can see with my limited equipment and lack of ability it’s impossible to do this absolutely perfectly but after the best part of 2 hours I was pretty happy with the result.
The right hand tank cover was next and although this looked slightly simpler it was in fact technically a bit more difficult to get all the folds right. The trouble is as soon as you’ve made a fold you can’t get the pair of angle irons right across for the next fold and have to stop them short and use G cramps. Here’s a pic of this panel before I assaulted it. This took over 2 hours but I finally got there. I then had to fit some clinch nuts and trial fit the panels. This is where life got a bit difficult. My problem was that the fold in the little triangular piece that goes between the bulkhead panels is critical and mine was a mm or so out. This shifted the panels across slightly and even if I hadn’t drilled the chassis already I couldn’t really have corrected it. It wasn’t a major problem and I did get everything to fit although I had to elongate a few holes lightly. They’re behind the seat so really aren’t an issue.
After lunch I downed tools to go on a little shopping spree. First stop was Livermore’s for painty bits – some etch primer, paint for the chassis, RAL code 6018 for that (seems to be a rather bright lime green ), also satin black two-pack. Then on to Machine Mart for a new mask, new spray gun and a couple of other bits and pieces. After that it was Screwfix for a nice 4.5 litre tub of the orange Swarfega and a pump to go on it. I got home, unscrewed the pump to fit it to the lid, bits shot everywhere (large spring involved) then it took me the best part of an hour to solve the puzzle of getting it back together and clear up the resulting Swarfega spatter all over the kitchen!
I did make it back out to the garage to sort out the fuel tank covers. These actually fit together very pleasingly and I was able to mark the chassis for the remaining rivnuts, drill the holes and get them fitted. Getting everything lined up took a couple of remove, fettle panel and refit cycles but by the close of play all the holes were done, all the rivnuts fitted. Getting rivnuts lined up can be tricky and I’ve learned that you need to be patient and get the holes up to the correct size in 1mm increments, i.e. not go straight from a 4mm pilot hole to the final 7mm hole as they tend to drift slightly off centre if you aren’t careful. I also find a 6mm hole in the panel being screwed on works best for 5mm as the extra clearance gives you a bit of wriggle room. Here are a couple of shots of the result of my labours, I’m rather pleased with it. Once I had it all fitted I removed all the panels for final finishing ready for painting and fitting.
The fuel tank will run the full width of the chassis, the taller bit on the left houses the fuel filler neck and in the current race car the filler cap is welded into the large hole you can see in the top panel. Since I want mine to get through IVA this won’t do and we’ll need to route it up and out of the side of the bodywork, Ian’s working on a plan for this.
TNT’s website informed me during the day that my engine had arrived at Brian’s and I had a confirmatory email from Brian so I gave him a ring in the evening. He reports that the engine is looking pristine with no external damage at all. Ian has it set up ready to take all the measurements to do the mounts for it. Brian also thinks there should be sufficient clearance to remove the clutch cover without fitting a removable chassis rail (as they’ve had to do for the ZX12 engine).
Ian has emailed me with a schedule for delivery of the remaining kit, unfortunately Bob at Concept Racing is going on hols so this will put the delivery date for the next batch of parts to mid August. This includes the front and rear sub-frames, wishbones etc. Brian uses Concept Racing for the welding of these parts as they’re designed to quite fine tolerances and the strength and evenness of the welds is critical. He also does the welding of the fabricated aluminium parts like the fuel tank and swirl pot. His welding is really top notch, Brian pointed me at his website to see some examples of his work, including a fuel tank for a Maserati, the parts for which are entirely hand shaped and it’s all riveted with no welding at all! It’s no surprise that he’s a busy bee and has quite a lead time.