Belt Up And Park Your Seat

 

So this update is primarily concentrating on the seat belts and the associated fixing bolts. I managed to drop on again on eBay and pick up some suitable four point harnesses which are very similar to the Cobra. I specifically wanted the aero style rotary clasp and black webbing, so being a tad specific I have been keeping my eyes peeled for some time for some to crop up at a reasonable price, and I managed to get a pair for only £50 which is a huge saving than if I purchased them new and direct with Willians. 

The lower two strap fixings are fitted with eye bolts the inner of which utilises the original Spitfire fixing point on the chassis. The outer one is simply drilled through a bracket that was installed when I put the chassis outriggers and out rails on and then the spreader plate is fitted underneath allowing the eye bolt to bolt through from above. I’m going to fit some sound deadening pads to the floor pan sections under the seats, I fear this will be a tad boomy if not. The under seat void is going to be a real bummer for loosing stuff, as I’m fixing both seats without runners, so I might make a little baffle plate to stop stuff rolling around and getting impossible to access because of the seat position. 

Next was to move onto the top fixing positions, which unfortunately I didn’t really photograph or document very well, however I’ll explain my process and you will see from the images how the basic structure was made. 

I started with a length of flat bar steel (3mm) which creates the horizontal and this was cut to length and curved each end to match the body tub. Remember my rear bulkhead is 2mm steel as opposed to plywood so it already has a good tensile strength and I’m just beefing everything up and adding some bracing to help absorb any impact that it might have to deal with. 

Once this was cut I had to define my position for the top two eye bolts. With the seat roughly in position I measured each bolt equally off the centre line of each seat back and at the height that would keep the fixings below the rear seat squab. Then it was easy just to drill a small hole through and marry up with my rear horizontal brace. I specifically made sure that the measurements allowed the fixing holes on the rear brace to be on the horizontal centre line so with the spreader plate behind also giving the most strength to the setup. I simply mirrored my fixings on the offside to the nearside to give me both sides, then I moved onto making the whole thing solid and structural. 

I dug out the pipe bender again (Christmas money well spent a few years ago now) then I had to put a small curve into each support tube in order to clear the petrol tank. 

I learnt from last experience to mark each tube equally with masking tape, then by positioning each tube in the same place each time it gave me a fighting chance of making a pair the same. They turned out really well and I was pleased that I only had to put a slight radius on the one end. Triangulation is the strongest form to create strength, but I could use the tubes without a slight kink as they voided on the petrol tank, which is as low as possible already to keep the centre of gravity down. 

With the two tubes bent I was able to cut the mitre into the bottom end and weld it onto a 6mm steel fixing plate, which is then bolted onto the chassis using the original fixing positions on the rear suspension cross brace. The other end of the tub was then tacked to the rear horizontal cross brace I had just made so I was then able to remove the whole rear bracing and beef up all the welds along with tarting it all up with some paint. 

With both braces in place and painted it was really really solid and should be more than sufficient for its purpose. However I hope I should never need to test this functionality…. Better safe than dead haha. 

The next niggle I had was a little knocking where the rear braces bolt down through to the chassis. When I fitted the boot floor I kept everything as low as possible to keep the petrol tank down as mentioned previously. This in turn has allowed the boot floor to rest on the chassis mounts, and despite being bolted through and torque down tight it was still allowing a slight tapping/knocking between the flex of the alloy boot floor and the chassis top mounts when giving it all some movement. I was aware of this issue prior to the seat belt fixing braces, but this has now accentuate it slightly and I was reminded when I was giving it a bloody good wobbling when I fitted them. 

I have solved this problem by unbolting the lower fixing bolts from the newly made bracket which has allowed me to slide some strips of rubber between the chassis mounts and the underside of the boot floor, then when everything has been bolted back down I was able to stand in the boot (on the rear diff) and bounce up and down with no knocking or tapping whatsoever…. Great success!

Next on the list of jobs was to fix the seats into position. The seats have to be secure obviously but not to the same extent as the seat belt fixing braces, still I belt and braces everything I do so I doubt it will be any different for this task. 

I started off with some strips of flat bar steel (4mm) and after offering the seat shell roughly into position I started making some lengths to support the front and back of the seat shell. I have cut the prop shaft cover so that it doesn’t act as a spacer on the one side for the brackets as I’m trying to keep the seats as low as possible and 1-2mm higher on the one side all adds up and would technically not sit the shell flat. Once these strips were cut they have been fixed into the chassis and outer sill but using countersunk machine screws as the seat shell would sit on the bolt heads if using a standard bolt. Again these don’t have to be super strong as such because any force acted upon them is the weight of the seat shell only, the body weight mass is transferred to the harnesses and the seats would stay in position as they have little mass in comparison to a human. 

Next I added two further strips of flat bar steel to give more support for under the seat. I cut them to length and welded them into position so that the seat frame becomes one piece ready for painting. I could then fit the seat into position and really get a flat solid mounting position which felt much more substantial. I made four fixing bolts through the seat shell into the now complete seat frame and secured using some M8 bolts and rivnuts. This will allow me to remove the seats easily should I want or need to later on. 

Now I was able to fix the seats shells and the new harnesses and really get a feel for the driving position overall…. I was very happy to be fair. Yes it’s bloody tight and small but that is the nature of the car. I will have to be friends with whoever is in the passenger seat as they will be very close… but overall it feels very engaging and I think it will give a rewarding driving experience. All switches are in easy reach and visibility is good with all the gauges and warning lights. I’m extremely happy that I fitted a removable steering wheel boss as this has made getting in and out significantly easier. Just the passenger side to do also and then I can start making some commitments on getting the seats trimmed, along with some interior  trimmings that I have a few ideas for also.