Building a GD427 Cobra Replica

The rear hubs have been waiting for 2 parts to be galvanised; the water throwers. I bought these new as the originals were very pitted and dented.

It costs something like € 70,- to galvanise a box of parts. It does not matter if that box has 2 bits or is cramped full. So, I’ve been gathering things to fill the box with, but kind of struggled to get a reasonably filled box. As I do want to finish the rear end of the suspension soonish, the box was delivered to Galvin to process. It should be back here within 2 or 3 weeks or so.

Not sure how I am going to fit the throwers onto the hub though. There is a small edge on the hubs over which the throwers should be ‘clicked’. Obviously I do not want to damage the throwers so I’ll either need to find a way to equalize the pressure over the circumference or heat it up so it sort of drops over it automatically. The edge seems to be smaller at the bottom than at the top, so heating it seems a plausible way to go.

Once I get them back, I’ll give that a try first.

Last week I got the last two missing thrust washers for the front lower wishbones. Eager to do something I assembled the left side at the front. Should have been an easy job, but I had a hard time putting the inner thrust washers in, because the wishbone is a ‘GD fit’. Took me the best part of an hour which should have been a minute job.

The other wishbone is even worse, something which I already noticed when fitting the GD brackets to them. I think I’ll have to construct some sort of temporary press to push the wishbone arms a bit apart to be able to fit the right side.

On the other hand, pressing the water deflectors on to the uprights was an easy job, using the press.

I’m running out of nordlock washers, so I’ll order a few next week. Once I have them I can finish the whole front-end I guess. I had planned to do the rear-end first, but I think I’ll create the same wheelbarrow as Andy did.

With all the bearing cups in place in the rear hubs, the only thing which prevents me from completing the rebuild of the rear hubs, is to determine how many shims are needed inside the fulcrum. My info says the goal is to have a negative end float of 2 thou, which is kind of unusual. (Negative meaning you actually preload the bearings by assembling the hubs?)

The steps to get to this are not that hard. Basically what you do is build up the hub around the fulcrum shaft mounted in a vice. In the picture you see the black space tube over which the hub slides down. In the jaguar parts catalog this tube used to be two smaller tubes with the shims between the two tubes. Now, the shims can be placed on either side of the tube.

To determine how many I need, hopefully an even number so I can put the same on either side of the tube, I put a known amount of shimming (on top of the tube in the picture), making sure it is going to lead to a positive endfloat. I just used the original shims plus a couple.

Placing everything on the shaft and filling the end up with some spacers and fastening gives a hub with a measurable endfloat which will be positive. Because I knew how many shims I had put in and I know what it should be, I can calculate what the actual number of shims needs to be.

I’m not sure how accurate this all should be as most of the fellow cobra builders tend to send their hubs to Ward Engineering or equivalent. In the final buildup you’ll need to grease the hell out of the whole fulcrum. I’m also going to use a modern style seal instead of the old 3 piece one. The felt piece in the classic seal feels a bit dated, although jaguar fellows keep telling me it works fine.

You’ve probably noticed I have carefully avoided mentioning the actual measured endfloat and the amount of shims in the above text. This is because I lost the post-it on which I had written those numbers down, and I don’t trust my memory so I have to do the whole thing again. Oh well…

After the trial run, which went well, I painted the components of the rear axle today. Planning to do the front axle tomorrow. The self fabricated rack of some wood and old heating pipe worked well.

I’m still wondering about that por15 stuff. I’ve never seen anything like it. It’s hard to capture the finish in pictures, but perhaps these two give an idea.

Especially in the second picture, the finish almost looks ‘metal-ish’ The spots are the original welding spots. Quite happy with how it turned out.

I also pressed the bearing cups into the front hubs, that is, only the large ones. The smaller bearing actually turned out to be too big! What gives? This bearing comes out of the wheel bearing kit LM258, which contains a Timken LM12711. The old bearing had a LM12710 cup, which has an outer diameter which is about 0.7mm smaller. The inner size of the two is the same, so the roller from the LM258 kit can be used.

Looking at several sources on the internet, I’m not sure what to make of this. I am not 100% sure of the precise year/model of donor I have, but I can not match the smaller cup with a Jag model / year combo, whereas the larger cup is mentioned for several.

Shrug, best get the smaller cup next week and be done with it I guess.