Evening star., 1915-11-21
TESTS OF THE OILS
BESTFOR CYLINDERS
Should Contain No Animal
Fats and Keep When Ex-
posed to Air.

fabrication consists of placing be-
tween two surfaces that have relatively
great friction cushioning and almost
frictfonless substance that will sepa-
rate these surfaces and enable the parts
to move with the expenditure of less
power" says r. T. Gray, manager of
the technical bureau of the Haynes Au-
tomobile Company
Friction is the retarding force that
tends to prevent movement of all parts
which are in motion. 1t is caused by
the interlocking of tiny projecting par
ticles which extend from the surfaces
of all substances like the surface of a
fle, regardless of their nature or the
fneness or finish. Power is required
to overcome friction in all cases, and
the greater the amount of friction the
more power will be needed to overcome
IT, In some parts enough friction ex-
lists to cause the parts in contact to be-
come SO hot that they swell and conse-
auently bind together.
The Principal Lubricants.
THE principal Iubricating mediums
commonly used are fluid oil and semi
huid oils and greases derived from both
mineral and animal sources Flake
lubricants known. is a. form of crys-
0Iline carbon. The oils best adapted
differ with the nature of the work the
parts are to perform An oil that is
suitable for one portion of the auto
mooiie mechanism may prove actually
injurious to other parts
The lubricating value of an oil is
dependent upon Its successful mainte-
nance OF proper oil film between the
moving surfaces and the amount of in
ternal friction in the oil itself.
The cylinders are the most difficult
parts to lubricate satisfactorily on ac-
count of the heat generated, and great
care is necessary in selecting oils for
this purpose. By adding about one ta-
blespoonful of ground fake graphite to
every gallon of cylinder oil it Is pos
sible to carry to all surfaces a material
that Is finer than the most minute pores
Of the metal and which will gradually
cover the metal with film which heat
cannot destroy easily. The benefits de-
rived from the use of graphite in oil
are many, for which continued use all
the bearings, cylinder walls and piston
rings are protected by a lubricant
which coats the metal All graphite
is not lubricating graphite, however
nor Is all lubricating gra phite suitable
for use in cylinder oil. Care must be
exercised and only finely ground flake
graphite of the best quality should be
used.
Basis of Cylinder OIL.
Cylinder oil should be derived from a
crude petroleum base because oils of this
nature are not liable to decompose by
exposure to the air or by heat, as are the
lubricants derived from animal fats or
vegetable sources. The presence of ami
mined by exposing quantity of the sus-
pected Oil to the air. If ii turns rancid
and has a foul smell this may be con-
sldered good indication that injurious
qualities are present
The presence of acid is not desired be-
cause this will produce rusting or eating
out Of the brightly finished bearing sur
faces and will roughen them so that they
have considerable friction. Oils that con-
tain acid are much quicker to act injuri-
ously when used in the cylinder because
they are rapidly decomposed by the heat
Of the engine. A simple test for acid in
oil can be made by dissolving a small
quantity of the oil in alcohol which may
be 81 ghtly warmed by placing the con-
tanning vessel in warm water. This will
make the dissolving easier, especially IL
heavy greases are tested. When the
lubricant has been dissolved the solut on
may be tested with litmus paper, which
may be procured at any drug store. A
piece OF blue litmus paper wn turn red
when placed in the solution If there is
acid present
the body of oils and is measured by al
lc-',g a given quantity of the oil to be
tost~A o escape from conta ner a drop
at a time. When two oils are compared
for viscosity the one that flows from the
container the quicker is the more fluid,
and therefore has less viscosity than one
Of heavier body. which cannot fow so
rapidly In some parts It Is necessary
that oils have considerable body, these
points be ng where heavy pressure exists.
al
gears.
The High Flash Point.
1.-THE fash test is an indication of the
amount of heating an oil win stand be-
fore the vapors given Off will fash or
catch fire. Cylinder oils should have
high fash point, SO that they will not
be vaporized from the cylinder walls as
soon as they come into contact with the
hot products of combustion. The fire
test Is really a continuation of the fash
test, and is the point where the oil be-
comes sufficiently heated 50 that II burns
steadily. The cold test shows the point
at which the oil will become SO stiff that
IL will not flow. A suitable oil for winter
use should not stiffen enough at zero
temperature to prevent its flowing to the
bearing points.
"The best cylinder oils are obtained in
three grades-lght. which has a consist
ency slightly greater than machine oil:
medium. which is somewhat heavier than
the light. and the heavy oil. which has
the consistency of warm rnolasses. Any
pure hydro-carbon oil having high de-
gress of viscosity at 100 degrees r. hav-
ing vaporizing point of about 200 de-
grees F.. fash point between 425 and
500 degrees r and ffre test Of $50 de-
xrees r. or over should give good salts
faction IN the cylinders.
''Buytng a cheap grade OF oil because
Of the low price 10 not true economy,
but will eventually prove to be q very
expensive practice. BY following the
above suggestions and using care in the
purchase and use Of lubricants the
motor VIII run easier. there will be less
friction and consequent expense. ard
the useful life OF the car will be pro-
longed"
Cadillac Eioh% pnrchoaers