The knock or pound caused by the cross-head slides not fitting the guides properly, may be remedied by adjusting them both top and bottom to fit the guides closely, being careful not to get them too tight, which causes undue wear and strain upon the frame.
The knock or pound caused by wrist-pin or crank-pin becoming worn flat or oval, may be remedied by filing them perfectly round.
The knock or pound caused by the piston leaking, which causes cushioning, can be remedied only by having a tight piston.
The knock or pound caused by the driving pulley key being loose, can be remedied by driving the key in its seat; or if a defective key, replace by a new one perfectly fitted.
If the knocks or pounds are caused by lost motion in any of the revolving, reciprocating or vibrating parts of an engine, they may be detected and located by placing the finger upon the different parts while the engine is running very slowly or worked back and forth by hand.
HEATING OF JOURNALS.
The heating of journals and reciprocating parts of an engine may be attributed to the following causes:
Improper proportions and fitting, unsuitable material, want of homogeneity between the metals of which the journals and bearings are composed, the revolving or reciprocating parts not being in line, the boxes being keyed up too tight, sand or grit getting into the journals, improper lubricating, etc. The last mentioned cause is very complicated, as the conditions of weight of load, area of surface subject to pressure, velocity of movement, etc., must be taken into consideration.
To remedy the heating of journals which is caused by the revolving or reciprocating parts not being in line, the engine or shaft must be put in line.
When caused by the boxes or bearings being too tight, they must be loosened a very little at a time until bearings run cool. Apply plenty of good oil.