How do you keep a Lister at the proper temperature?
The Lister 6/1 likes to run at 180F and above, I have been running mine with 195 degree thermostats and think it's pretty close to the sweet spot for this engine, but it could be much higher.
How important is the proper temperature in this engine and other water cooled designs? I think it's very important, I offer a story to expand on my experience, and more important, the experience of my friends. Manufacturers don't put thermostats in water cooled engines just to make the heater work! George's big Lesson
Here's my approach to control the coolant temp in the Listeroid with a minimum investment. actual tests with radiators and cooling tanks proves the auto thermostat works great.
Here's a picture of the stock upper coolant port on the Lister. Note that stock fitting will accept 3/4 NPT pipe threads, the thread count is the same, I use some sealer to assure no leaks, as the British thread does not taper as the NPT does.
Step one, use a die grinder and a stone or carbide cutter to port match to the gasket. You can see the pattern from the gasket around the port, I left some additional material. Some of these stock Indian coolant ports are barely open, I recommend you open them up before you put them to work.
Next, fit the thermostat into the head and assure that alignment with the flange is correct.
This picture shows a thermostat from a Plymouth Horizon slipped into the port. The first generation setup used a spacer plate and a stock flange, the spacer plate had a small recess cut into it for the lip of the thermostat, not shown.
Here's a picture of the NAPA 253 thermostat, you can invest a bunch of time sorting through thermostats to get the right size, but this one has proven to work well, some have a little hole in the valve to make it easier to chase the air out of the system, make the hole, especially if you will be draining the coolant and recharging it often.
I found the above flange in a Hardware store with a good pluming section, the manufacturer is Northwest Cooper, and they call it a Waste Nut of all things. It's tapped with 1" NPT threads and ready for the pipe nipple you see screwed in. Put the assembled unit on the lathe, and turn in the recess for the thermostat as you see here. the hole pattern matches the Listeroids I have experience with, and it also works well with the hopper plate conversion for Chinese Horizontal singles. also note that this waste nut comes in 3/4" and 1/2" sizes, so it may be a solution elsewhere.
As for radiators and coolant tanks, a big electric water heater tank works great for a cooling tank, simply unscrew the heater elements, screw in an off the shelf nipple fitting, and elevate the tank above the engine where all hose connections move upwards with no dips. It's easy to find a solid tank in the salvage yard. Leave the insulation and sheet metal behind if you can.The tanks look nice when painted to match the engine.
Another great way to manage coolant temps is to use an old cast iron radiator that was used in a hot water system. Many houses and other buildings used these, and some older homes make use of them today. I have personally tested this set up with a 6/1 and found it to work real well with the same thermostat mentioned above. And of course, you can use a car radiator, if you do, use one that has upper and lower connections, don't use a cross flow for thermal siphon setups.
It helps to remember that you will not be shedding as many BTUs as a modern automobile, this may help you realize that you do not need the same efficiency in your coolant system. I have not seen a need or advantage for a water pump in my applications. Of course the key is to install a temp gauge at the upper coolant flange and then load the engine fully, let the gauge tell you if you have engineered the system properly. You can always add a fan if you need it.
If you could place a Lister lower than your living space, you could mount one of these old radiators up against a wall with a nice polished sheet of alloy or stainless behind it, this setup would radiate lots of heat into a living space when desirable.
As of this date, I have two readers who have managed to overheat their Listeroids to the point where there was little paint left on the head that wasn't black, or white. The CS plug got so hot that no residue of any type remained! a third person reported that his head was so hot that the oil around the valve guides was smoking! Modern engines would have made their final trip to the scrap yard after being overheated to this extent. All three of these failures resulted when open type cooling systems lost enough coolant thru evaporation to break the thermal cooling loop! Be careful and make sure you have a complete understanding of the thermal cooling loop.