50 



BULLETI]Sr 119, U. S. jSTATIONAL MUSEUM. 



ing and the elimination of any center bearing coupled with the 

 counter balancing of the crank shaft, these difficulties are reduced to 

 a minimum, and the crank shaft is kept true at any engine speed 

 without distortion. 



Another feature of the engine is the lubrication system. The oil is 

 circulated by a gear pump driven from the cam shaft and located in- 

 side the lower engine pan. The oil is retained in a reservoir in the 

 bottom of the crank case, where it is kept cool by the current of air 

 continually passing around it. From this the oil is drawn by the 



FIG. 21. FOUR-CYLINDER GASOLINE AUTOMOBILE ENGINE, 1921. 



gear pump through a heavy double strainer and forced under pres- 

 sure to four standpipes, one directly beneath the center of each con- 

 necting-rod bearing. Each standpipe has a hole drilled on either 

 side near the top, and at slow engine speeds oil flows out of these 

 holes into a small cup-shaped pan secured to the standpipe beneath 

 the oil holes. Inserted in the bottom half of each connecting-rod cap 

 are two tubes extending inwardly to the connecting-rod bearings and 

 of such a length and so spaced that when the connecting-rod cap is at 

 its lowest position the tubes touch the oil in the cup-shaped pan and 

 draw a small quantity up to the bearings. As the engine speed is in- 



