[kaiser]

Yes, the material used is mild steel, mostly in thick walled tube. The interconnecting straight piece is made from a piece of round bar.
I have used a lathe, hacksaw, welder, paint, normal tools, swearing, band aid and half a case of beer. It has taken me the best part of a week!
The thermostat itself is a 82 degree from a BMW.
It is not too difficult to make. All the sealing areas need to be machined to ID 37.4 and the part fitting in about 37mm. Then you need an O-ring to seal it, seated in a 3x3mm groove. The seal works amazingly well.
The hardest part was getting the fit right, and getting the big holes drilled in the pipe. Welding the darn thing was easy. Making it leak proof was not! (My welding is maybe not as hot as I thought!)

I am still thinking of making a cast brass or aluminium unit, but my set up cost makes it necessary to get about 20 units ordered minimum.
The cost of the units would then be in the region of 150 Pounds. With volume, we could get it down.
The advantages are.
1. You can select any thermostat temperature.
2. The unit will not crack or leak with age. All plastic is verboten!
3. I have mounted a temperature sender right in the centre. Can be used for add on gauge.
4. You can replace the thermostat only, keep the housing.
5. I have modified the bypass valve, so that it blocks return into the engine at 70% of max opening, as opposed to 100% standard, I hope it provides a wider margin of safety.
6. I have allowed a little by pass by the thermostat, even fully closed. That should lessen vapour lock, and give a little bit of protection if thermostat gets stuck, and lessen any shocks, thermal and temperature. A bit longer warm up might be the result.

I can't tell you how it works yet, because I have not yet put the engine back together. But I will keep you all posted. I'll jump out of the window if it doesn't!!!!!

If there are enough people intersted, I will get some units cast. Let me know, but budget at around 150 for housing, pipe and bend. The final cost can be determined if and when orders are placed.

But let us first see how it works. By the end of next week I would imagine I should know!

Oh, and yes. I am busy with a level sensor, which you can build from funny things most people have lying around! More of that later.