Building a GD427 Cobra Replica

Continuing with little jobs to finish the rear end backend. First up was the final assembly of the top bolts on the diff. It’s not exactly clear to what value these should be torqued, but I guess the value of the original Jaguar bolts will come close. The lock-wire went considerably smoother than earlier (on the diff bracket). I only needed 3 attempts this time!

On to the front, there are six bolts on the suspension which need their head drilled for the lock-wire. Mostly a patience job, making sure the bit gets cooled properly and preventing to much pressure on it. 5 bolts went fine, during the sixth the drill-bit broke. As such that isn’t a disaster, you count on the smaller bits to break soon, but the bit got stuck in the bolt! The bolts are jaguar specific and as such a rip-off (around the € 10,- mark I believe). Having no choice, I ordered a new one.

Having the bench drill now is essential, a hole like below just would not be possible by hand. (1.5mm hole, 2.5mm finish)

Back to the back again. The handbrake mechanism comes with two extra helper springs which somehow need to be attached to the chassis. There are two or three locations which would be suitable, but only one of them was reachable with the rivet tool I have. It remains scary to drill holes in the chassis.

At the right bottom you can see the black dot of a more preferable location (it pulls on the spring straight instead of in a slight angle), but unreachable for my tool.

As I need to clear the complete garage by monday, having the cobra on wheels and rolling was necessary. Although this is a (self imposed) deadline, when the thing was on wheels and actually rolling it did feel more a milestone than I had thought.

Again, I have to applaud Gardner Douglas for their ‘fit’. The differential and the chassis get together by 8 bolts, 6 of which drop in pretty easily and the rear two need a little flexing of the diff cage; exactly as outlined in the build video.

Today I rolled the chassis to the garage of a nearby friend. It will stay there for the next week while work is being done in the garage. My girlfriend did take some pictures of the cobra’s maiden voyage. Alas, there was no card in the camera, so no pictures of that. (Not that it was that spectacular anyways.)

The trip, however small, was useful though. You get all sorts of information you do not get by keeping the chassis static. Here’s what I learned in 300 meters rolling the car from one garage to the next:

• the routing of the brakeline needs rethinking, on full steer it touches the tires; (I imagine it will be even worse with the wider wheels which will be fitted)
• there was a slight ‘tick’ at the rear left (hand-)brake caliper, could be the brake-pad;
• old tires, all different and a suspension not setup make for a crappy ride;
• it is very easy to lose nuts and bolts if they are not tightened;
• inertia of moving mass is easily underestimated;

So, not much to do for the next week but nag with my suppliers for delivery of the gearbox, which seems to be the bottleneck in the delivery. The gearbox fit also determines the precise length of the propshaft (so I’ve been told), so partial delivery also doesn’t make sense either. Patience… (more…)

Unable to set a good time-slot apart for the treatment of the donor parts, it needs like a 6 hours slot for all the painting and cleaning, but eager to do something, i started to do some chores on the chassis.

I started with putting all nuts and bolts from the chassis kit loosely in place. This is to see if i got them all, but also thinking that their destination is probably the best place to keep them instead of in a drawer somewhere.

Next up was getting some (more?) wax into the inside of the chassis. Finding a small enough applicator which would also fit the venturi attached to the compressor turned out impossible, so one throwaway aerosol it is then. An easy 15 minute job with nothing to show for. I needed some more…

Still somewhat hindered by the thought of not doing things in order for the build I instead created a storage place for the bottom plates of the car-lift.

While a useful end result, I realised I was just making up excuses and needed a ‘real job’, so, I decided to do the front-brake-pipe run. Here’s the end result:

Gave me good pair of sore thumbs. I can’t attach the p-clips to the chassis yet, as i want to use the same rivets as GD has been using, but I do not have such a rivet gun yet. I feel another tool purchase coming up next week

Went to speedon yesterday to fetch the chassis and the assorted bits needed to help me construct a rolling chassis.

I should probably stick to the proper order and first finish revising all the jaguar bits, but it’s very tempting to start putting things on the chassis. M.u.s.t. r.e.s.i.s.t….