While it is hardly possible to prescribe a remedy for all cases, if
the following practical methods are closely followed they will be
found to be very useful, although in many instances the remedy must be
determined by the circumstances of the individual case.
The knock or pound of boxes in connecting rod at cross-head or crank
pin or the valve rod, may be remedied by taking out the boxes, and
filing off the top and bottom inside edges sufficiently to allow them
to just come together and not fit the pin too tightly. In replacing
them, be careful not to key them up too tight.
Where there is not sufficient draught in the key or gib, place a liner
in front or behind the boxes.
Knocks or pounds in the link may be remedied (if the link block has too
much play in the link) by reducing the liners in each end of the link
enough to fit the block properly.
The knocks or pounds of piston are caused by the rod becoming loose
in the head; and if allowed to continue, will destroy the fit of
the rod in the hole. It may be remedied under such circumstances by
removing the rod, re-boring the hole and bushing it perfectly true, and
refitting the rod.
Knocks or pounds of follower plate are generally caused by dirt
accumulating in the hole, which will not allow the bolts to enter far
enough to take up the lost motion of the plate, or the bolts may be too
long. To remedy this, remove the accumulation of dirt from the hole, or
shorten the bolts.
The knocks or pounds in main crank shaft, if caused by the bearings
being worn oval or out of round, may be remedied by removing the shaft;
true it up in a lathe, and refit or re-babbitt the boxes.
The knock or pound in eccentrics is generally caused by the eccentric
straps being too loose upon the eccentrics, which can be remedied by
reducing the liners in the straps to allow them to fit perfectly.
The knock or pound in slide valve caused by being improperly set, may
be remedied by taking off the steam chest bonnet and re-adjusting the
valve so as to give the same amount of lead at each end of stroke.
This being done, and the valve well proportioned and the connections
properly fitted, there should be no knocks or pounds from this cause.
The knock or pound in cylinder caused by shoulders being worn in it,
can be remedied by re-boring the cylinder, being sure to make the
counter bore of sufficient depth to allow the piston rings to overlap
them at the end of each stroke.
The knock or pound on guides caused by shoulders being worn on them, is
remedied by planing the guides and making the shoe slides of sufficient
length to overlap the guides at either end when crank is on the center.
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.