The Washington times., 1918-12-07
NOECONOMY IN
BUYING CHEAP OILS

Cap stretched himself. emptied his
pipe in the ash tray and stood up.
There's a salesman comes around
to see me about once a week with q
new oil that never heard of. Either
his price is low or his oil isn't fit to
use. We're going to find out which.
I've got a sample in the laboratorgp
He poured a small quantity of the
oil into a beaker. placed 1t over the
flame of a burner and suspended
thermometer so that the bulb was in
the oil
This is the fash test. 1t is the
lowest temperature at which the vapor
rising from the oil will ignite without
setting fire to the oil. No matter what
the flash point may be, no oil can
withstand the explosion temperature
above the piston. but below the piston
high-flash test oils have a decided ad-
vantage. Did you ever stop to con-
slider where the oil goes after you
Put 1t in the crankcase?"
NO; but suppose 1t gradually
gets above the piston and is burned
up"
That's part OF Il. The rest of it
evaporates and passes out through the
breather. The amount of this evapor-
alton depends upon the flash tempera-
ture. Oils with a low flash point lose
such a big percentage by evaporation
that there is no economy in buying
cheap. inferior oil. Now watch this
sample in the beaker. The tempera-
ture is getting somewhere near the
flash point I'll light this taper and
bring it near the surface for an in
slant. See that! The vapor burned
for an instant l didn't expect IL so
soon. Temperature was only a little
ever 800, and IL should be nearer 400
for the flash point Now, we'll heat II
some more and get the fire point. That
Is the lowest temperature at which
the oil itself catches fire from the
vapor. The process is just the same
and the temperature should be about
80
The viscosity test is important and
requires a special piece OF apparatu,
but there are certain tests that any,
one can make. There! see that oil
burn. Temperature too low. Well. let
me show you how you can test an oil
for the presence of sulphuric acid COM
pounds Take that clean bottle there
on the bench and I'LL II one-third full
OF oil Then put in an equal amount
OF water and shake II BY the way,
might mention that you have to shake
for half an hour.
Then it must stand for twenty-four
hours. Good oiI-and by the way the
test can only be made with pure hydro
carbon oils-will show a clear white
line between the oil and water. I'm
pure oil will form a curdled emulsion
that floats on the top. leaving the
water below a milky white
There's a cold test to determine the
lowest temperature at which an oil
will flow, but that doesn't tell anything
about its lubricating value. II might
be important II. for instance, you were
to keep your car in winter In an un-
heated garage. The cold test Of the
oil you use should have a temperature
pretty close to that Of the cold motor.
Oils can be compared for evaporation
by comparing the percentage Of loss
when the same amount OF heat is ap-
piled to each Then there is another
important test which you can make
any time
You can compare two oils by actually
using them, provided you use them un-
der the same conditions, running the
engine the same length Of time in each
case and at the same temperature. The
results you get will only be approx
mate, but the difference in the amount
VI SSuiilcHt Will DC enough 50 Indl you
can draw conclusions.
"When you consider that your cheap
is depositing a bigger percentage
Of sediment and Is also losing a bigger
percentage through evaporation. you
see how little economy there is in buy
ing IL.
''Viscosity is expressed as the number
Of seconds for a definite volume Of oil, 1
under an arbitrary heads. TO flow
through a standard aperture at con- ,
slant temperature. usually 100 degrees
Centigrade or 212 degrees Fahrenheit
The usual light oil is about $50 sec
onds. Medium oil runs up to 800 sec
onds- Heavy oil may be as much as
$50 seconds.
The grade OF oil has an effect on
horse power and fuel consumption. The !
use Of light oil Of 80 seconds generally I
gives the minimum fuel consumption Q
and the maximum horse power, but
more Of 1t is needed. as consumption ;
is correspondingly higher. Therefore !
the solution Of the problem is a COM
promise that depends almost entirely |
on the engine In which the oil is /
used."-Winsor Reed Davis, in October |
Motor Life.