GAS, OIL AND ALCOHOL ENGINES 



423 



engines and where the amount of water used may be un- 

 limited, the constant-flow method is considered the best, 

 since by this means the water can be drained from the 

 jacket every time the engine is shut down, and turned in 

 again upon starting, and thus avoid the danger of 

 freezing. 



Open-jacket cooling. Engines are now coming upon the 

 market which have the open-jacket method of cooling. 

 The casting for the water jacket is extended so it forms 

 a reservoir upon the top of the engine (Fig. 3110). This 

 reservoir is open at the top and holds but a few gallons 

 of water. As the engine heats, the water is allowed to 

 boil and evaporate. Since there is only a pailful or so of 



water in the engine, it is 

 but a small matter to drain 

 the engine and then refill 

 in cold weather. 



Oil cooling system. By 

 having a radiator and cir- 

 culating pump, oil is used 

 for cooling where engines 

 are exposed to freezing 

 temperature. 



Often chemicals are used 

 in water to prevent freez- 

 ing. Calcium chloride is 

 the most common of these. 

 The proportions generally 

 used are 5 pounds of the 

 chemical to 10 gallons of 

 water. Whenever possible, 

 FIG. 31 1 A OPEN- JACKET SYSTEM the use of chemicals should 



OF COOLING ., , , 



be avoided; they attack 

 either the tank or the engine castings. 



