408 



FARM MOTORS 



Cylinder head. The cylin- 

 der head (Fig. 289) should 

 have a device for cooling. If 

 water is used for this, the in- 

 side of the head should be at 

 least y$ inch thick for a 5- 

 inch cylinder and the water 

 jacket not less than Y^ inch. 

 These dimensions increase 

 with the size of the engine. 

 Cylinder. The cylinder 

 (Fig. 290) should be bored 

 perfectly smooth and round, 

 and should be free from all flaws and imperfections. It 

 may have the same thickness of castings as the head. 



Base. The base (Fig. 291) should be designed to carry 

 the cylinder, engine frame, and flywheels in a well-bal- 

 anced condition. 



FIG. 289 CYLINDER HEAD 



FIG. 290 CYLINDER 



