Lister CS Thermostat Kit

To avoid any difficulty in working out how to fit the thermostat housing an explanation is required, so here goes.

There is basically two acceptable methods of fitment that we know of, if you have another suggestion, please let us know. We have not included the placing in of the gaskets in some of the pictures to make it clearer to see but please don't forget to add these when you assemble your thermostat kit.

Firstly, for those who are unfamiliar with how a thermostat works we think it is important that you have a basic understanding so here is a very brief explanation. Within the thermostat there is a small copper capsule which contains a thermo-reactive wax substance. As the wax heats up it expands and pushes the seal open allowing water to flow, similarly as the wax chamber cools it shrinks and allows the seat to close and seal off the water flow, thereby creating a self regulating temperature control. The whole thing is held with a small framework and has a spring to keep some resistance in place. Hopefully now you will be in a better position to be able to reason with yourself as to why the wax filled copper chamber really does need to be as close to the cylinder head as possible where the water is going to be heated first to work correctly and not facing in the other direction i.e. to the cold water!

Method 1,

You can see the order of assembly in the picture to the left.







Using this method the thermostat body is facing into the cylinder head as it should but is also partly in the holding flange.

 

For the thermostat this is really not an issue, we have tested both methods and this placement seems to offer equally good control. However, if you intend to fit a threaded stub pipe as shown in the first picture into the next flange as many do, you may find that the threads of that pipe fowl on the portion of the thermostat which protrudes away from the cylinder head. We found that this can be easily overcome by trimming the threads of the stub pipe down so that they finish a few mm short of the flange face.

So long as you still have sufficient threads in the flange for a secure, water tight fit, we can see nothing wrong with this solution. Bear in mind that the first few BSP threads of the pipe are the smallest because it is a tapered thread and most likely will be serving little purpose anyhow, unless of course your taper is very tight at the outset in which case it should not protrude that far through the flange anyway.


Method 2,



You can see this alternative method of assembly in the picture to the left.






This method may require some slight modification of your cylinder head with a die grinder or half round file. We consider this to be perfectly acceptable so long as you apply common sense and reasoning i.e. don't go mad! The casting tolerances of the cylinder heads will have been fairly slack so not every port is going to be exactly the same size. The engine we tried to fit the thermostat to needed only the lightest tickling with a half round file, most of which was to remove the years of scale but you may find you need to open up your port by a mm or so.

You can see what you are aiming to achieve in the next series of pictures below.

 

 

 

Doing this will allow the thermostats wax filled copper chamber to be right where the action is, in the cylinder head! It goes without saying that this is the preferred method because it then leaves your second flange free to accept your stub pipe as well as placing the thermostat in the best position.

So there you go, the choice of which method to use is yours, best of luck!!