To mitigate heat and noise intrusion into the cockpit I decided to fabricate an closeout panel to separate the fuel tank compartment from the engine compartment. Some builders decide to do nothing, some build a solid panel (and don't put anything else in the compartment) while others make a full-length panel with an access door so that they can service the low-pressure fuel system.
I wanted to locate the low-pressure system in the compartment, but I realized that even with an access door it would be very hard to service it once the body was on and the high-pressure fuel system was installed. So, after much thought I decided to cut a hole in the floor to service the low-pressure system. I'm pretty sure that I'm the first builder to take that approach.
The close out panel is very simple in concept, but it was a lot of work to finish. The first step was to cut some 0.1" aluminum to the rough size. After that I cut notches around the 2x2's on the floor and then I coped the sides around the weld beads on the chassis. I must have had the panel in and out of the car 40 times to get it to fit perfectly – lots of measuring and small cuts means no big mistakes! Once that was done I drilled and tapped 37 holes
Before tapping the holes I mounted the panel with clecos. As discussed in the video above they come from the aviation industry and are extremely useful when fitting panels. I thought that the panel fit perfectly, but when it was held completely flat by the clecos I discovered it was too wide. It was easy to remove all of the clecos, trim the panel and reinstall it.
My daughter helped me tap a bunch of the holes. I thought that I was teaching her something until she explained that she had used a much larger tap to extract tree cores. I then explained the purpose of cutting fluid and once again she was not impressed, "Dad, we coated the tap with wax to do the same thing." LoL so much for me teaching her something.
Once this was done, I cut holes for the fuel filler tube and the shift cables. Although the fuel filler tube is round, I had to make a slotted hole because the fuel tank must be rotated when it's dropped in. Fortunately Will was visiting when I did this so the cuts came out perfect.
Next I covered the engine compartment side with heat shield. It can withstand direct continuous heat up to 1,750° F, but the embossed 10 mil aluminum skin dents easily. I used a special rubber coated roller to ensure it laid flat. Any resemblance to my daughter's beloved pastry roller is purely coincidental. I thought it would be easy to trim the overhang with tin snips, but that didn't work well. I found that a Dremel cutoff wheel worked OK, but the glass-fiber core made a huge mess (if you go this route, do it outside and wear a mask!). In addition, when I drilled the holes the adhesive film hardened on the drill bit... so I had to clean the drill bit 37 times with a razor blade.
I then fabricated some brackets out of right-angle aluminum to seal the sides. Once this was done I installed Second Skin Damplifier Pro on the side that faces the cockpit to deaden vibrations. The last step was to install the panel with 10-24 screws and Permatex Black RTV Silicone Sealant.