During my time employed as an engine tester at Listers, All canal star engines were tested with a fail safe electrical protection system incorporating an oil pressure sensor fitted into the crankcase cam gallery and a water temperature sensor fitted into the water pump housing. These were connected via the wiring loom to an energize to run fuel control solenoid conected to the fuel rack shut off. If the engine suffered a loss of coolant or loss of lubrication oil or drive belt failure to the water pump,the solenoid would shut down the engine safely and before any major damage could occure. The engine could only be restarted with the manual operation of a system overide button.