Building a GD427 Cobra Replica

Having a rolling chassis is nice, but having it rolling of the hoist is another thing (not that this has happened yet). So, a working handbrake seemed like a logical thing to do next. The original handbrake end-bracket was to small for the supplied handbrake cable. Adjusting it (by cutting a slot in it) did not seem a good idea, as it would create a very small contact area for the bit at the end of the cable.

In one of the drawers at speedon Mischa found something that could fit, and with a bit of effort, it indeed did.

(apologies for the blurry picture) With a bit of sanding on both parts, i.e. the cable and and the bracket, made it fit.

The ECU has arrived too with a nice semi-assembled harness. Now I need a handful of connectors and I should then be able to construct a complete harnes and finish that part.

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…)

I am working towards a situation where i can fit wheels to the front temporarily, so the chassis can be positioned over the rear end, not unlike a wheelbarrow. After that I’ll want to fit temporary wheels to the back as well because the garage needs to be cleared out by the 20th of July. After we created the new floor, some cracks started to appear and I made an arrangement with the contractor for repairs this summer.

So, that means we’ll need to clear out the whole garage, again, and having some wheels on the chassis makes that a whole lot easier. Ideally I want to have the suspension set-up completely by that date, but we’ll see.

One thing I noticed at the front was that the damper bracket opening was a bit smaller than the one on the left. This is probably caused by the welding process which puts strain on the metal and causes it to bend. We’re talking 2 milimeters I think. With a piece of thread and two M12 nuts I carefully widened the bracket a bit, just enough to get proper clearance on the damper.

Moving to the front…

Apart from one bolt I’m missing for the front (the one I had got damaged somehow) I’m also going to need two pieces of brake pipe for connecting the flexible hose to the front calipers. Looking at most other GD builds and the pictures I have from GD, the routing often does not make sense to me, so I’ve experimented with some different configurations. Basically, there are 2 things to vary:

1. the positioning of the donor bracket (upside down / normal);
2. routing of the flexible brake hose, what I’ve called ‘north’and ‘south’.

Positioning the bracket seemed to quickly lead to the ‘upside down’solution for me (see also Simon’s post, although he reaches the opposite conclusion)

Next, the routing of the flexible brake hose. The ‘northbound’routing seemed to work best for me. It does not come anywhere near any suspension part, neither in full bump, full droop and at both extremes of the steering.

I find that another advantage of the northbound route is that the routing of the fixed piping is greatly simplified, just needing a short piece with two bends, instead of routing it through the caliper openings.

It may of course be the case I’m missing something completely, as the setup with the upside down bracket and the northbound routing of the hose is basically different than everyone elses setup?