16a
Even more V8 cooling tips
Lothar Taverne (Glacier White 5001) from Vienna has a Costello MGBGTV8. This note has been prepared with help from our Swiss member Tom Studer (Damask 0109).

There have been several contributions from members on this well known problem with MGBGTV8s. I would like to show another approach. It is not only the cooling system that determines the temperature of the engine but also the fuel/air mix plays a major part too. Every combustion engine that runs on fuel works best when the fuel and air are in the proportion 1:15, although an engine will run up to 1:6 (which is much too rich) and down to 1:18 (which is far too lean). By running on 1:18 you would save considerably on fuel, but it raises the temperature in the cylinder head and therefore loads the water and oil circuits. To get the highest output from an engine, it is essential to run on the right mixture - which is a little enriched - and to maintain this mixture constantly so the fuel and air get mixed which improves the evaporation of the fuel.

Now if you drive the car hard on a lean mixture, the temperature of the engine will rise even more, but there is a way to find out whether the mixture is too rich or too lean. It is advisable to have a second person to assist with a fire extinguisher - don't worry. The only other thing you need is a spray phial which resists fuel. Sprinkle a little fuel in the air cleaners and if the mixture is not too rich enough the engine speed will increase or it will decrease if it is too rich. If it stays constant, the mixture is fine.

Now that the mixture has been adjusted there are a few other things which can be improved.

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Adjusting the temperature at which the fans cut in. Firstly when the original thermostatic switch comes in too late, the effect is the accumulated heat cannot be cooled down satisfactorily. You can fit a Kenlowe switch and with this you can vary the temperature at which the fans cut in. By varying the "cut-in" temperature, you can find the best temperature at which the fans should come on.

Removal of the bimetal "cookers". You can remove the "cookers" or "claws" which are the air intakes for the circular air cleaners on the standard set up.

Fan size. Another way of improving cooling is to improve effectiveness of the fan blades. Kenlowe do a 10 blade fan instead of the four blades on the standard fan. Unfortunately the diameter of the Kenlowe fan is too large, so the 10 blades have to be cut down. Even after cutting down the blades, each has about 40 sq cm more surface. It is also advisable that the fan blades are located as close to the radiator matrix as possible. When cutting down the blades, considerable care will be needed to ensure the fan unit is balanced to avoid vibration in operation.

More segments in the radiator. It is possible to fit more segments in the radiator water cooler box when a rebuild becomes necessary.

Checking ignition timing. It is essential that the ignition timing is checked because this also influences the temperature of the engine. Check also the distributor shaft and the drive for wear which has an effect on the timing.

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