New-York tribune., 1918-01-27
By II. Clifford Broka.v

:.
counted, you are likely to be surprised
when you check up the several hundred
bearing points Of the modern automo-
bile
A bearing is a support for moving
member, so designed as TO minimize
sriction and receive wear and to per
nit Of fine adjustment There are
many types Of bearings, some in which
the metals are selected with the idea
If obtaining strength rather than non
friction qualities. Others have strong
metal shells lined with comparatively
soft non friction metal. In these bear
ings moving members slide over each
other.
In addition to this we have the so
called anti-friction bearings, in which
balls or straight, taper or helical roll
ers are used, giving a rolling rather
than a sliding contact.
In the average siX-cylinder engine
alone there are 102 bearings. Some
have more than double the number.
There are. for instance, the following:
lO2 Bearings in Engine
Six cylinder, six wrist pin. six crank
pin and four main bearings, all of con-
siderable size; three cam shaft. twelve
cam, twelve push rod, twelve valve stem,
two fan, two water pump, three oil
pump, eight ignition, six spark control,
six carburetOr control, six carburetor,
four self-starter and four self-starter
linkage bearings.
You did not think the first named
was a bearing, did you: The cylinder
and piston are not generally termed
bearings, yet when you reflect on it
they are the largest in the. engine.
Both parts are usually of cast iron,
which gives comparatively long wear
and in which the friction is not great
wear does occur at this point. it is
necessary to rebore the cylinder and
have larger pistons fitted.
The wrist pin bearings usually are
in the form of a bronze she'll. called
bushing, surrounding the wrist PIN
When wear occurs it is necessary to
drive out the bushing and replace with
a new one which fits.
The crank pin bearings are usually
IN halves, the metal being babbitt or
bronze, surrounded by steel strap or
SdSlliS. [NuJ SlIlcuL lOT wear is H1duo
by taking out thin sheets of metal,
called shims, which allow the halves
to be brought closer together. The
main crank shaft bearings are of the
same type.
Cam shaft bearings usually are bush
ings which must be replaced when
worn. Cam follower bearings may be
simple fiat plates resting directly upon
the cam. or rollers running on pin
in the valve push rod. Wear usually
is compensated for by adjusting screws
on the push rods. The push rod guides
are sometimes made of cast iron or
shell in bushing form; they are to be
replaced when worn.
Bearings That Rarely Fail
Oil pump bearings being perfectly
fabricated, since they run in oil, sell
dom or never require adjustment.
The bearing may be a plunger working
in small cylinder, with one end bear
ing against cam, or pair OF gears
driven from the cam shaft.
All of the bearings considered so far
are cared for by the lubricating sys-
tenn of the engine. which starts opera
tions when the engine starts to run; SO
long as oil is kept in the engine they
are quite certain TO be taken care of,
barring accidental stoppages of the oil
lead. Now we come to others which re-
qure separate oling by hand through
squirt can or by turning a grease cup
cap.
The fan bearings usually are of the
ball type and fabricated with squirt
can. Being almost always of the cup
and cone type, they arc adjusted by
tightening the cone. Water pump bear
rrS 1,ih otoj INV
grease cups. When Worn badly it is
necessary to drive out the bushings and
replace them. Generally the shaft also
will need replacing. When this shaft
becomes worn out or round, no amount
of tightening of the stufling box Will
prevent water from leaking out.
The valve stem guides are sometimes
bushings, but more usually are holes
bored through the cylinder casting. In
the former case, when wear occurs the
bushing may be driven out and new
one, with new valve, installed. In the
latter case the holes must be reamed
true and larger and valves with larger
stems be inserted.
In the Ignition system ball bearings
usually arc employed, with or without
means of adjustment. These are lubri-
Gated with an oil can or packed in
grease. There is one bearing of the
ignition system which is unique in
that some manufacturers advise keep
ing it free of lubricating substance of
any kind. This is the rocker arm of
the lntcrrupter on certain makes of
magnotos. Other forms of interrupters
are so constructed that fabrication is
advisable
The carburctor air valve bearing on
crates better if not fabricated. II does
wear and needs replacing at times. The
throttle bearings may be fabricated
lhey would certainly wear longer if
TINS were done, but it seldom is. When
they do wear air is admitted. which is
noticeable at low engine speed, causing
Skipping and irregular running. Then
the holes in the casting must be en-
iarged and larger shaft inserted.
Throttle and spark control linkarc
nave number of bearings, which NAV
be OF the steel ball and socket type. or
a wire bent TO fit in an eye These pins
should be fabricated frequently with a
squirt can Usually they are not ad-
Justablc so that parts must be replaced
when ;hcy arc bad y worn.
Ball Bearings in Motor
The self starter motor and generator
usually arc equipped with bali bearings
and arc fabricated with a squirt can.
Both the motor and generator have A
copper commutator on which carbon
brushes hoar Thoco no ,,ot