96 SCIENCE OF SUCCESSFUL THRESHING 



drops into one of the marks on it, the engine will be on 

 either of its dead-centers. With engines, on which the 

 crank-disc is not easily reached, the prick-punch marks 

 for the tram are usually located on the fly-wheel rim. They 

 were so placed on "Case" center-crank engines. 



In placing the engine on its dead-centers, in examin- 

 ing the valve setting, or in setting the valve, it should 

 always be turned in the direction indicated by the reverse 

 lever, that is, if the reverse lever is in the forward end 

 of the quadrant, the engine should be turned "under," 

 or in the direction in which it runs when threshing. If 

 turned past the mark, it should be turned the opposite 

 way and again brought to the mark, moving in the right 

 direction. This eliminates any error due to lost motion. 



To Determine if the Valve Setting has been Disturbed. 

 New engines have their valves set at the factory before 

 being painted, so that broken paint often reveals the fact 

 that someone has re-set the valve. Besides this indication, 

 "Case" engines are provided with marks, by means of 

 which, one can determine whether or not the valve setting 

 has been disturbed since the engine left the factory and, 

 if it has been disturbed, furnish the means to bring it back 

 to the original setting without removing the steam chest 

 cover. The eccentric hub and the shaft are marked, as 

 with a sharp cold chisel, so that the marks meet when the 

 eccentric is in its proper position. When one suspects that 

 the eccentric has slipped from its original position, an ex- 



