First Chassis Spine Removable Cover

With the Framehead repairs complete it's time to move on to the underside of the chassis spine. As a reminder, I had cut two sections of thsi panel out; one at the rear due to the original panel being distorted due to jacking the car in the past and the other due to the need to remove rust from inside the chassis spine. A byproduct of this process is that I can route pipework and locate components within the chassis spine easily during the rest of the build. Whilst this process does affect the torsional strength of the chassis, as this is a race car the cage that is to be fitted later will put the needed strength, and more back.

Starting with the longer of the two holes, the edges were trimmed and neatened.



Here we have the two panel pieces removed from the original spine section and also a second, almost complete spine section panel that I caferully removed from another chassis. You can see all the spot welds along the edges of this panel that were drilled out to remove it!



Next the appropriate section was cut from the donor panel, leaving sufficient spare length at each end to allow for accurate trimming later.

The panel was then cleaned up using a wire brush on an angle grinder and laid in place to ensure it was right.

Finishing up the Framehead

Into finishing up the framehead repairs this week.

Firstly the chassis spine was flipped over so it was right side up. Then a bit more welding.

 After that the welds were ground down. Masking tape was used to prevent the grindings going into the Napolean's hat and corroding later on.

Once cleaned up a coat of zinc rich primer was laid on to try and keep surface rust at bay until the full floorpan is painted.

Spine flipped over again and the welds ground down...

...and finally the underside was also primed.

One completed framehead repair!

Welding up the Framehead Closing Panel

Lots of welding this week!

Fully welding the various parts of the closing panel after tack welding them into position.

 Plug welding where the original spot welds were drilled out. The last piece of the closing panel was finally trimmed to size and checked for alignment.

The last repair panel (the black one in the above picture) was cleaned up, correctly aligned and tack welded into it's final position.

It's was then fully welded, completing the welding from the underside.

Continuing with the Framehead Closing Panel Repairs

This is the last part of the closing panel roughly cut to size, cleaned up and coated in zinc rich primer on the inside face.

Here you can see the above panel roughly in place. Again, the white circle on it was a dent that was dressed out before priming the other side. The rest of the closing panel is clamped in place and I've started to make the repair parts for each end, where the main chassis bolts pass through. Here they are roughly cut to size from the reproduction repair panel.

Now the end repairs are trimmed to a correct fit. At this point they were cleaned up, aligned correctly and tack welded into place. The whole panel was removed again and these repair pieces then fully welded.

The welds were ground down and the panel re-primed on the inside face.

The whole panel was then clamped back into place ensuring correct alignment and tack welded.

Finishing up the Napolean's Hat and Starting to Zip up the Framehead Closing Panel

Here we have the rear view of the Napolean's Hat with the repairs done, welds ground down and a coat of zinc rich primer over the top.

And again from the front.

With the chassis turned over you can now clearly see how the framehead closing panel was cut and how the replacement framehead was attached to the chassis spine. I also gave the inside of the Napolean's hat and chassis spine a coat of zinc rich primer after making sure no rust was left.

Here we have the other framehead closing panel, cut to match the part already in place on the framehead, all rust removed using a wire brush on an angle grinder, and coated in zinc rich primer. The small holes you can see are where the original sport welds were drilled out. These holes will be used to plug weld this panel back in place.

Trial fitting the closing panel in place for fit & alignment and also to check if any other repairs are needed. Doing this revealed that the ends, where the main chassis bolts pass through, were not as good as I hoped so I decided to make further repairs at this stage. The white marking on the lower right side was to highlight a dent in the panel. This was dressed out from the other side before the panel was welded in place.

The Napolean's Hat- The other side

With the left side welded the same process was carried out on the right side. In these two pictures you can see the extent of the removed metal (sorry for the less than ideal quality pictures, I think I must have been shaking a bit!). Also again note the way the framehead closing panel was cut to leave the original pressings intact whilst getting rid of the rot.

Repair panel cut and tacked in place from the back, once correctly aligned using the other new panels. This time the edge of the repair panel also needed some dressing as the quality of the pressing was not great Underneath you can see the original, corroded end of the Napolean's Hat...

...and the front.

Again this was then cleaned up and fully mig welded.

The Napolean's Hat- Repairs

From the last pictures you can see that the "Napolean's hat" panel needed some work. It was badly corroded at both ends and also along the joining point with the floor pans and framehead closing panel. Rather than replace the whole thing with a not particularly great pattern part, I decided to use only the parts of the pattern panel absolutely necessary. These bits would be cut out and welded to the original panel where needed, so leaving as much of the original as possible.


Here you can see the major rusted area, roughly cut out on the left side. Sat on top of the chassis spine is the part of the repair panel that will be used. It's worth noting that the repair panel is for a LHD car so has holes pressed out in places the original RHD part does not. In particular there is one hole that you can see in this picture. I'm not sure what to do with the hole at the moment, either weld it up or leave it and close it off using a grommet. I've left it pending a decision later on. In this picture you can also see the replacement framehead fitted and welded on, together with the remnants of the closing panel. As I mentioned before this was cut so that I removed the worst of the corrosion but was able to leave the original pressings and brake hose brackets intact.

Picture showing the front edge of the left side cut to the final point. Strangely the front edge, which is more exposed to the elements, was in better condition that the other side, so needed less original metal removing. Again you can also see the framehead closing panel.

Once the original panel was trimmed back to the marked lines, the repair panel was trimmed bit by bit until a good fit and alignmant was achieved. To make sure the alignment was spot on I temporarily laid the replacement floor pan panel, the replacement heater channel and the replacement front bulkhead panel in place. Here you can see the repair panel finally in place from the rear and prior cleaning up and welding.

And here from the front.

Next step was to weld it on after again ensuring alignment was spot on.