ake an
engine so different under different conditions, we find it very
difficult to give you the light on this part of your duty which we would
wish to. We, however, hope to make it so clear to you that by the aid
of the engine before you, you can readily understand the conditions and
principles which control the valve in the particular engine which you
may have under your management.

The power and economy of an engine depends largely on the accurate
operation of its valve. It is, therefore, necessary that you know how
to reset it, should it become necessary to do so.

An authority says, "Bring your engine to a dead center and then adjust
your valve to the proper lead." This is all right as far as it goes, but
how are you to find the dead center. I know that it is a common custom
in the field to bring the engine to a center by the use of the eye. You
may have a good eye, but it is not good enough to depend on for the
accurate setting of a valve.

HOW TO FIND THE DEAD CENTER

First, provide yourself with a "tram." This you can do by taking a 1/4
inch iron rod, about 18 inches long, and bend about two inches of one
end to a sharp angle. Then sharpen both ends to a nice sharp point.
Now, fasten securely a block of hard wood somewhere near the face of the
fly wheel, so that when the straight end of your tram is placed at a
definite point in the block the other, or hook end, will reach the crown
of fly wheel.

Be certain that the block cannot move from its place, and be careful to
place the tram at exactly the same point on the block at each time you
bring the tram into use. You are now ready to proceed to find the dead
center, and in doing this remember to turn the fly wheel always in the
same direction. Now, turn your engine over till it nears one of the
centers, but not quite to it. You will then, by the aid of a
straight-edge make a clear and distinct mark across the guides and cross
head. Now, go around to the fly wheel and place the straight end of the
tram at same point on the block, and with the hook end make a mark
across the crown or center of face of fly wheel; now turn your engine
past the center and on to the point at which the line on cross head is
exactly in line with the lines on guides. Now, place your tram in the
same place as before, and make another mark across the crown of fly
wheel. By the use of dividers find the exact center between the two
marks made on fly wheel; mark this point wit