Evening star., 1933-07-02
funds they were accepting through
Federal channels"
Need Of Changing Oil.

Need Of Changing Oil.
Infrequent changing Of contaminated
crankcase oil incurs serious risk IN
motor fabrication, according to Dr. II.
C. Dickinson of the United States Bu-
reau of Standards. who discusses why
Drain Crankcase Oil?" in Industrial and
Engineering Chemistry. journal of the
American Chemical Society. Dirt. fuel
vapors water, metal particles and other
foreign materials deteriorate the orig
inal substance in varying degrees OF
rapidity, depending on the type OF oil,
he says.
While crankcase oil serves the dou-
bic function of fabrication and cooling,
DR.. Dickinson continues, the latter is
of less Importance, as far as quality
is concerned, since the cooling process
is not affected by anything which hap
pens to the fluid in the crankcase. The
value of lubricant oil, however, de-
pends on it's viscosity at operating
temperature. SO the accumulation OF
contaminantS renders 1t gradually less
safe and effective.
"Oil changes should not be delayed
too long" he explains For example.
If a car holding quarts of oil in
the crankcase uses l quart of oil every
$50 miles, then in 5000 miles of opera
ton "a quarts will be used if changed
every 500 miles. On the other hand. If
the oil Is changed every 1000 miles
81 quarts will be used; whereas, eX-
tending the period of changing to l 500
miles would require the use of A
quarts.
The difference between changes at
500-mile and 1,000-mile intervals is
sufficient to merit real consideration. if
the type of equipment and of service
permits this iacrease in distance be-
tween oil changes. However. the 10
permits this increase in distance be-
tween changes at 1000 miles and at
1900 miles, in the particular case
risk in extending from 1000 to 1,500
miles between changes would hardly
be justified. While the above example
is fairly typical there are variations
in different types of equipment and
service"
Most of the dirt which collects in
lubricating oil has worked past the
pistCnS or is introduced accidentally
in servicing. Dr. Dickinson says. Core
sand or other foreign matter from new
castings may collect in the oil in new
cars. Fuel residues are found to be
less frequent in the lubricant because
of the greater volatility Of the gasoline,
while damage from water usually oc-
ours under severe cold weather condi-
tions where numerous starts and stops
are made.
Other Contaminants.
Other contaminants include partly
oxidized products, called asphaltenes,
which, he states, form in some oils
more rapidly than in others. In eX-
cessive amounts. they increase the
viscosity of the Oil and have tendency
to collect dirt. metal particles and
water into sludges. which, in extreme
cases. may clog oil passages and coat
exposed metal surfaces with a semi
solid deposit. Such deposits, however,
are not of frequent occurrence"
Cracked oil. caused by contact with
very hot surfaces, such as the under
side OF pistons. may lower the viscosity
and increase the amount of free car
bon. There is little evidence that
changes of this nature which occur in
the normal operation of motor We
hicleS are of any considerable i'm
portance, DR.. Dickinson adds.
Individual car owners should accept
the recommendation of the car manu-
facturer regarding the mileage between
changes, he advises. Organizations
owning a large feet of cars. trucks
or busses can keep an accurate cost
OF operation through facilities for test
ing the equipment and the crankcase
oil. Under these conditions the period
between draining the oil can be grad
ually raised from a known safe limit
until the optimum mileage oetween
changes Is found