New-York tribune., 1921-11-13
Bearings Are
Supports for
Moving Parts
Made So as to Minimize the
Friction i'm Your Car;
There Are Many of Them
and of Various Kinds
BY H. Clifford Brokaw
Technical Director, West Side Y. M
c. A. Automobile Schools


c. A. Automobile Schools
What is bearing7 Well, it is a sup
port for moving part, made so as
to minimize friction, stand wear and
achieve tinc adjustment. 1t would not
be bad idea ii more humans had
the characteristics of bearing.
There arc hundreds of these things
in an automobile, so one could hard
ly be blamed for losing just few. But
the loss of only few ght rnise merry
havoc with the machine, and put II
IN that drydock of the automobile world
the repair shop.
There are many types Of bearings
some in which the metals are selected
with the idea of obtaining strength
rather than non friction qualities;
others have strong metal shells lined
with comparatively soft non-friction
metal. In these bearings moving mem
bers slide over each other.
In addition to this we have the So
called anti-friction bearings, in which
balls, or straight, taper, or helical
rollers are used, giving rolling rather
than sliding contact.
On the engines alone there are more
than one hundred bearings. This is
motor; some of them have more than
double the number. There are for in
stance, the following:
Six cylinders, six wrist-pin bearings,
six crank-pin bearings, four main, three
cam-sh aft, twelve cam, twelve push
rod, twelve valve stem, two fan, two
water pump eight ignition, six spark
control, six carburetor control, six
carburetor, three oil pump, four self
starter. and four self-startcr linkage
gearings; total 1G2.
The first named cylinder and piston,
not generally termed bearings, are
usually of cast iron, which gies COM
paratively long wear and in which the
friction is not great if we'll fabricated.
When wear does occur at this point
it is necessary to rebore and have
larger pistons fitted.
When Wear Occurs
The wrist-pin bearings usually are
in the form of bronze shell, called
a bushing, surrounding the wrist pin;
when wear occurs it is necessary to
drive out the bushing and replace with
a new one which fits. In some cases
it is necessary to replace the wrist
pin also.
The crank-pin bearings are usually
surrounded by a steel strap or casing.
When wear occurs, the adjustment is
made 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.
The cam-shaft bearings are usually
in bushing form, or of ball type, which
must be replaced with new ones when
E-yI
bearings may be just fat plates rest
ing directly upon the cam, or rollers
running on a pin in the valve push
rod. Wear in these parts would usually
be compensated for by adjusting screws
on the valve push-rods
The push-rod guides are sometim e q
made of cast iron or other metal, with
babbitt or bronze shell in bushing
form, and would require replacement
when worn
The oil pump bearings consist of
plunger working in a small cylinder,
with one end bearing against cam,
or pair of gears driven from the cam
shaft. These bearings, being perfectly
fabricated, seldom or never require ad-
justment.
All OF the bearings considered so far
are cared for by the lubricating system
of the engine, which starts when the
engine starts to run. and as long as oil
Is Kept IN the engine they are quite
certain to be taken care of, barring ac-
cidental stoppage of the oil lead.
Fan Also on Bearings
The fan usually runs on ball bear
lngs, which are fabricated with a squirt
can, being usually of the cup and cone
type, that are adjusted by Tightening
the cone. The water pump bearings
are fabricated by compression grease
cups; when the bearings become badly
worn 1T is necessary to drive out the
oushlngs and replace them; generally
the shaft also will need replacing.
When this shaft becomes worn out Of
round no amount of tightening OF the
stuffing box will prevent water from
leaking out.
The valve stem guides are sometimes
oushlngs, but moro 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 lgnitlon system ball bearings
usually are 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 fabrication substances of
any kind. This is the rocker arm of
the interrupter en- certain makes of
magnetos. Other forms of interupters
are SO constructed that fabrication is
advisable.
The carburetor air-valve bearing op
crates better if not fabricated, but does
wear and need replacing at times. The
throttle bearings may be fabricated and
would certainly wear longer if this
were done. When they do wear air is
admitted which is noticeable at low
engine speed, causing skipping and ir-
regular running. Then the holes in
the casting must be enlarged and
a larger shaft inserted.
Pins Usually Not Adjustable
The throttle and spark-control link
age have number Of bearings, which
may be of the steel ball and socket
type or wire bent to fit in an eye.
These pins should be frequently lubri-
Gated with a squirt can. Usually they
are not adjustable, so that parts must
be replaced when they become badly
worn.
The self-starter motor and generator
are usually equipped with ball bearings
and are lubriacted with squirt can
Both the mtor and generator have
copper commutator on which carbon
brushes bear. These are not bearings,
strictly speaking, but they do require
very slight trace Of oil. The COM