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Does anyone know if a modern thermostat can be used in the Super 8? The only thing I'm finding on Max Merritt is a "Radiator Thermostat Syphon Unit" and the cost is a whopping $525. https://www.parts123.com/parts123/yb.dll?parta~partsort~A2~cadeffdA

Currently the engine has no thermostat in it. I'd prefer to have one in order to allow the cooling system to function properly. I'm hoping a modern one will work.

-Kevin

I am kind of curious where the cylinder head thermostat goes. There is a 162 degree thermostat #234941 mentioned in the service manual that can be used in cars with hot water heaters in conjunction with the 150 degree shutter unit but no views showing it. The cyl head thermostat is recommended to be removed in warm weather. For what its worth, the only thermostats I see listed in the Super 8 and Twelve parts book that was just added to the archive a few days ago is shutter, automatic choke, and heat riser. The number given in the SM for a cylinder head thermostat does not appear in the numerical index.

On the engine cutaway there does not appear to be a thermostat. Nothing in the head and I only see the water outlet with no extra view showing any internal items such as a thermostat or retaining ring as was done for other engines. In a view from the SM, with the way the outlet is drawn showing sort of a gap space at the bolting area there does appear a possibility a thermostat could go between the outlet bottom flange and the head. If that is the case I would think you could measure the diameter and pick up a 160 degree capsule type thermostat having a flange measurement that would fit in the gap area.

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Kevin: In addition to the spring wire retention there are other designs specifically to be used in cars that never had an OEM thermostat, or a convenient location in the goose neck to install one. The design that I’m familiar with is where a stainless steel T-stat is tack welded to a length of thin walled stainless tubing, and the whole mess is put into the upper radiator hose. If the T-stat is installed at the goose neck end the tubing works its way up the hose until a bend in the hose is encountered. It just sits there until you decide to change it. I’ve had the same one installed in my ‘Brand X’ for 18 years. I did put a good sized (#1 drill) bleed hole just in case the T-stat ended up at the radiator inlet fitting, which is likely considering the upper radiator hose is straight. dp

Interesting. It looks like thermostat I linked to is the shutter thermostat found inside the radiator. Mine works fine. So maybe the Super 8 had no thermostat on the cylinder head at all? I assume the cooling system would be designed as a whole to work without that thermostat.

When my dad bought the car years ago there was an aftermarket thermostat somehow placed on the cylinder head. When the engine failed and the block cracked, the presence of the thermostat is one of the things the mechanic thought may have caused the problem. That and a faulty impeller on the fuel pump, and a poor water distribution tube. It seemed to be a problem of poor water flow.

So perhaps I just run without a thermostat for now.

It brings up the question of proper operating temperature for this engine. I haven't found it in documentation yet. If the shutters open at 150, is the engine meant to be kept at a lower operating temp, like 160-170?

-Kevin

If you look at page 90 in the 37-38 service manual or page 87 in the 38-39 manual for the Super 8 engine, under thermostats it lists the temp ranges of the shutter thermostat options as well as discusses the cylinder head thermostat which was apparently only installed and was used to raise the water temp if the car had a hot water heater.

Thanks Howard, I went back and looked at those. You are correct. I think I'll just leave the cylinder head thermostat off since I don't plan on using the heater at all.

-Kevin