98 SCIENCE OF SUCCESSFUL THRESHING 



points do not drop into the marks, the eccentric rod should 

 be adjusted as to length until they do or else the valve 

 must be entirely re-set as explained below. 



How to Set the Valve on Engines with Woolf Reverse. 

 After having taken up all the lost motion on the valve- 

 gear, main-bearings, crank-pin and cross-head pin and 

 shoes, and being provided with the tram for placing the 

 engine on its dead-centers, as explained, proceed to set 

 the valve as follows : 



First. Length of Reacli-Rod. See that the "reach- 

 rod" from the "reverse-lever" to the "block-guide" is of 

 such length that the valve moves the same distance during 

 a revolution of the fly-wheel in one direction as for a 

 revolution in the opposite direction, with the reverse-lever 

 in the corresponding end notch of the quadrant in both 

 cases. The entire distance the valve moves, which is called 

 the "valve travel," may be conveniently measured on 

 the valve stem by the tram, as illustrated in Fig. 31, or 

 by a pair of dividers or compasses. To do this hold one 

 of the tram points in the punch-mark on the stuffing-box 

 and, with the other, make scratches across the rod as the 

 fly-wheel is slowly revolved. If the "valve travel" be 

 more for one motion than for the other, it shows that 

 the reach-rod is either too long or too short to give the 

 proper angularity to the block-guide, which angularity 

 determines the travel of the valve. This rod can be easily 

 adjusted to the correct length by taking the pin out of the 



