Quite a bit of fiddly work involved if someone is making them manually on a lathe.

Maybe a retired watchmaker?

Not really an answer to your question but I bought a stack of generic exhaust studs a couple of years back for a stationary engine I was rebuilding.
They were high tensile steel and copper plated. The copper plating seems to be pretty standard for exhaust studs. Why? corrosion resistance? easier to get them out again? I don't know.

Nice job, Sloth.
Is that a 3D printed panel I see? I might steal some ideas.

Welcome back to the forum Hoppy.
You have had a turbulent time over the past 12 months. Good to see you back mate.

I did away with the ash tray a long time ago. I have fitted an air pressure gauge and a manual switch for the aircon fans.

With the flap closed it still looks standard.
The picture was taken a while back I see. When the aircon worked. Book symbol is now on, like most peoples.
A job to do in the spring when the weather warms up.

I have got the diesel and I have wired up the aircon fans with a manual overide switch to supplement the cooling. The fans still work as they were designed with the aircon but I can also switch them to full speed/half speed/auto. Auto has a thermal switch fitted in the radiator top hose.
It is never needed driving solo in UK weather, but towing in 40 deg C weather on the continent it has come on. My engine is also chipped and puts out nearly 50% more power.
I have also kept the viscous fan. It is far more powerful than the aircon fans.
If your vicous fan was noisy there was something wrong with it. I can't hear mine normally. When running hot, the viscous unit grips and the fan comes on with a faint roar under the bonnet. Yours must have been on all the time particularly if it reduced mpg. Best thing is to replace the viscous unit and re fit it.
There is a temperature sensor in the head that is wired back to the BECM and FIP and god knows what that monitors the engine temp. I know the engine power is cut automatically if it detects it overheating. Don't mess with it would be my advice. Could cause unforseen problems.

Bolt, the tank does look very nice. I am surprised it is hand welded, I would have thought Allisport would be more automated.
The genuine BMW plastic tank is the best part of £100.

It has been a while since I did it, but when you take the speedo head out and take it apart you will see pockets or recesses behind the front panel where bulbs stick through. There is a thin black sheet in front with symbols etched into it for the various warning lights. If you hold it up to the light you can see them. I have a few spare speedos and they are all slightly different. Petrol or diesel, manual, early or late but there will be unused ones or just make a hole and stick in an LED. I used the one with 2 gear cogs. Is that traction control? Anyway it was not used on mine. There was no bulb behind it.

One thing you might consider as Mad-as says is fabricating a special rear bumper which incorporates secondary rear lights in them. Phase 2 of the project.
It would allow you to move the wheel right over to the right and shorten back the arm. The canterlever forces would be less.
You could even have a second arm on the other side with a couple of jerry cans on it. They would both hinge outwards and lock together in the middle position. Unless you do something with the lights you couldn't do this.

The top half of the tailgate has to lift up first to unlock. It would not clear the wheel with that arrangement, which would be mounted on the bottom.

I have also had a Discovery. The side opening door was a pain in the ass. I like the drop down tailgate, it is a lot more practical. I much prefer a p38.

erm ... I don't think it is that easy, Symes.
You are thinking of welding up the top and bottom half of the tailgate and fitting side hinges?
Structural work to support a side hinge door plus the weight of a spare wheel bouncing round off road would mean major reinforcing.

I can confirm the pictures are visible.
Impressive work JL. The engineering and thought that has gone into your project are first class. Drawings are excellent.
I look forward to seeing how the fabrication goes.

You can change the one under the top cover easily enough. You need the special socket for the security bolts. Then replace them with ordinary cap head bolts. If you remove the next part with the electronic gubbings, it will alter the FIP timing, so mark it's position first. It slides forward and backwards to adjust. It can be done in place.
You can also change some of the o-rings under the screws as shown in the diagram.
I would not disturb the rotor head to get at no.2 in the pic. I would do it on the bench.
Note that the electronics bit under the top cover is unique to a p38 and specially made by Bosch. A BMW one has the wrong protocol if someone is thinking of swapping it over.

It alters the gearbox change points. I use it when towing my caravan in hilly country. In "sport" it hangs onto the gears more .I have got the diesel though.

It is a pity the gearbox ECU can't be chipped or reprogrammed so as to have bespoke settings. My diesel puts out more torque than standard and has an uprated torque converter.

Years ago I spoke to Mark Adams who said he could do it but nothing became of it.

Yes, I have fitted one to my 2000 DSE; actually the very same Allisport model in your pic. It was many years ago. Like 10 or 12 years at least.
I did a number of other changes around the same time such as chipping the engine and fitting a larger intercooler, so it is hard to quantify any performance increase due to just the EGR removal. I also messed with the spring on the turbo blowoff and screwed it down to give 1.3 bars. Normally it is set at 1.0 bars g.
The Allisport fitting is just straight through inside. The exhaust connection on the top and the vacuum pipe connection on the bottom are dummies.
With the blanked off exhause pipe and vac tube in place, everything looks the same to a casual observer or MOT guy. Not sure if EGR is on the test though but mine gets through OK.
It has worked well. Allisport welding and fabrication is good.
The EGR is there to recirculate exhaust gases back to reduce emmissions. Problem is turbos, I think all of them, throw out oil to a greater or lesser degree into the compressed air side of the turbo. When the turbo is worn a bit, it can be too much and the oil gets through the intercooler and into the inlet manifold. It gets burnt by the exhaust gases and congeals or carbonises causing a mess.
I noticed the inlet was a lot cleaner as well as being straight through. There is no central valve mechanism like the original EGR valve.
Later on, I also removed the vac pump and fitted a blanking plate off a BMW car. Can't remember which model. It tidied up the front of the engine as well.

To be fair a split in the hose can be difficult to detect.
Years ago my car suddenly went down on power and put out a lot of smoke from the exhaust when I put my foot down.
There was also a sort of whistling sound in the background (most diesel owners are already obsessed with engine sounds!).
I was convinced it was a hose, or hoped it was the hose and not the turbo. I couldn't see anything amiss but I eventually found the split in the hose that goes from the turbo to the intercooler. It was on the engine side. The only way to check that area is to take the RH wheel and plastic inner liner off. I still couldn't see it but I could feel it blowing with the flat of my hand with the engine running.
Splits are usually a tear in the fabric used in the construction and will close up when there is no pressure. The turbo runs at 1 bar pressure but doesn't really reach that until 3000 rpm. At tickover it is more or less atmospheric pressure. Starts to build from 2000 rpm onwards and max'es out at 3000 rpm when I measured it with my Faultmate.

Yes, yours is the EGR version, but you would be better off removing or disconnecting the EGR valve. It will run better.
I have not seen a silicone turbo hose kit as such. When I did mine, I just measured up and fitted a few bends with suitable aluminium joiners.
Try: Ash silicone hoses They are pretty good.
You will also need a couple of decent turbo hose clips. Jubilee clips are not up to it.

The car should not use any coolant at all. You must have a leak somewhere.
The coolant level on my 2000 DSE stays the same all year. It settles just below the seam on the expansion tank.
I must have had every kind of leak over the years though, You need decent hoses and clips all round. I have replaced a lot of mine with silicone hoses and I have fitted constant tension clips using the special tool. I am not a big lover of jubilee clips.
At the back of the engine there is a U shaped hose that connects the head to the block. It is out of sight and as Tanis8472 says, it can leak. It is a favourite place. Also take the plastic cover off the injectors and have a look underneath.
You can get leaks into the cabin but it would be smelly and get noticed. I have also had the bearings in the water pump go causing a leak. The fan also caught slightly on the radiator damaging one of the tubes. I had to practice my aluminium brazing skils.
The expansion tank is a source of leaks. You need to fit a new cap. Only get an OEM BMW one. The threads on the expansion tank can also get worn. My level was dropping a fraction of an inch over several months until I managed to come across a new tank. I have fitted a BMW M3/E34 tank with a level probe, but it is very similar to the p38 tank.
I also invested many years ago in a cooling system pressure tester. The one I have is a US made by Stant. It is just like a big bike pump with a pressure gauge. It wasn't cheap and it also needed a BMW adapter to screw the pump onto the tank.
It has proved it's worth. Just pump it up to 12 psi or so and leave it for a few hours. It does not test the cap however.

I have got my transfer box to do in the new year. FYI it weighs 75 KG, so definitely a two man job and preferably using a 4 post lift.
I am converting the "manual gearbox" version of the transfer box to the "auto gearbox" version first, so I will have an unused set of manual epicyclic set of gears left over if anyone is interested.

Plastic does become brittle with age, particularly ABS.
The plastic top of my (OEM) radiator burst a couple of years back with a big bang. I think it was about 15 years old at the time.

Not quite the same thing, but when I wired my auxilliary towing socket (the white 7 pin 12s one in the UK), I took it straight from the battery with heavy duty cable. Just a fuse in the line. No switch or anything.
It powers the caravan fridge via a relay in the caravan which only energises when the engine runs. I have not had any problems with sync due to that. Never needed ferrite sleeves either. It is an absorbtion type fridge 12v/240v/gas.
A compressor type fridge will take a fair amount of current on startup. I would be reluctant to take a heavy feed from the BECM. Better direct from the battery imho.