Building a GD427 Cobra Replica

Fetched about half the ordered parts from speedon on friday. The other half still wasn’t there! Come on GD, I’ve been waiting forever now. Apart from unpacking and identifying what is what I went about on a trial fitting spree.

The gearbox was the bottleneck for delivery, (Tremec == GM so that may have something to do with it). It is here now but still without a flywheel and clutch assembly, so the only thing I can can do with it is temporarily mount it on the adapterplate and bell-housing and put it away for a while until the other bits arrive.

The throttle valve was converted to a cable operated one, but on assembly to the engine it touches some little pipe behind it. (what is that, anyway?) So, some adjusting to be done there.

The engine mounts go together with an adapter plate. As assembly they are mounted onto the engine in two steps, easy peasy. I noticed the mount does not mount flat onto the adapter plate, should there be a rubber between them or is is just forced onto it? On final assembly I’ll get back to that.

And finally, the modified thermostat outlet. I’m going to polish that a bit later on to smooth out the welds a bit. Also, there are basically 2 ways to mount the outlet. Shown here is the one where the outlet is most ‘outwards’. If the outlet is turned 180 degrees it moves a bit inwards. When the engine goes in the chassis I’ll have to revisit this too, judging what’s best at that time.

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.

So, the garage has yet again a new floor. The top one of the images below is from the current situation, the one below it is from the first attempt (already 2 years ago!). Spot the differences…

Let’s hope this time the cracks will not appear. Having to clear out the garage, store everything somewhere and put everything back is definitely not my idea of a good time.

On the cobra-building front it’s a bit quiet due to lack of parts, though I could do a few jobs on the chassis and suspension I guess, but for many of them I want to be able to take measurements of the engine, gearbox and other stuff before I do them.

I have been assured that the parts will be available for collection next week, so it should not be that long before I can get cracking at a slightly higher pace.

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… Read the rest of this entry »