Evening star., 1932-03-06
OIL BIC PROBLEM
Of NEWER AUTOS
Carbon SpoiIs Motoring Fun
and fabrication Should
Be Studied.

With high compression bringing
carbon once more into the limelight as
motordom's biggest pest the eyes Of the
motor world are turning to lubricating
oil as one of the major problems of the
day. Oil makes carbon. Carbon spons
the high compression party. Motordom
is worried.
1t wouldn't be SO great a problem If
the public knew a little more about oil
control. Things would not be SO bad II
every car owner had some sort OF idea
Of what happens to oil after he pours
it into the crankcase. But as matters
stand the engineers have to fight the
situation with unfair odds. There are
the piston rings, and the public Is
familiar with only two of them.
Most drivers realize that II the
cylinders are worn there is more op-
portunity for oil to get by the ringsr
Most Of them also know that If the oil
isn't the right grade, or is Of in
ferior quality, 1t will work by the rings
and burn up. That's about the extent
of owner appreciation Of what today
has become one Of the most far
reaching factors in service.
Hundreds Of thousands Of motors of
the high-compression type now are
knocking their heads of for no other
reason than because oil control isn't
properly understood Soon the number
will run into millions. AS these newer
motors wear and as no consideration
is given to the why's and hows Of oil
loss past the pistons the knocking from
oil-made carbon will become a cease
less torment. Yet prevention Is rea-
sonably simple.
Many drivers will have to learn not
to operate the accelerator so erratically.
Whenever your foot is lifted from the
accelerator suddenly, while running
along fast in conventional gear, there is
a powerful suction within the combus-
ton chambers. This causes oil to be
sucked up past the rings, regardless OF
how efficient or how tight the latter
may be. This practice is advisable when
the car Is being driven steadily at top
speed because 1t helps to cool the CYL
inders and because there is sufficient
heat to burn the oil clean. At normal
or suow speeds this practice simply
draws UP oil and converts it into car
bon. Frequently with free wheeling
there will be less Of this.
One of the greatest mistakes is
wrongful use Of heavy oil. II a driver
finds that he is using too much oil he
grade on the theory that the more Wis
cous oil will act as a seal and will be
slower to work up past the rings. The
theory sounds well, but in practice en-
gineers find that II the piston rings
happen to be a little lacking in tension
they will partially collapse and thus
ride over the film on the cylinder walls.
The oil, therefore, has a free outlet to
the combustion chamber.
Not infrequently at high speeds rings
"fiutter." This has been found to be so
noticeable In the case OF some cars that
oil is actually blown out Of the motor
breather pipe. Where such poor con-
tact is found the explanation lies in
the fact that the ends of the rings nut
ter. In somewhat the same category
are warped, twisted and out-of-round
piston rings. Such conditions are due
to poor manufacture or faulty installa-
ton, although they can develop from
abuse in breaking in the motor.
A great many cases OF oil pumping
have been traced to unequal Tightening
of cylinder head bolts The cylinder
block becomes distorted. Another COM
mon cause of oil pumping Is the out-of-
round cylinder. Particularly in a small
bore, high-speed motor the rings do not
have an opportunity to become well
seated, making contact only with the
higher sections of the cylinder walls.
Many drivers still go down hill with
the ignition of. This eliminates COM
bustion pressure and allows oil to pump
up into the cylinders. Although it is an
old reason for oil loss the excessively
hot engine Is a more important factor
than ever because with higher compress
sion and higher speed the efficiency OF
the cooling system is Of far greater con-
Germ than ever before. Heat thins out
the best oil, upsetting all normal con-
ditions with respect to oil control.
1t does not seem to be generally
known that improperly timed valves will
waste oil. If the intake valves are
timed to open too late there Is an un-
usually long suction period which ma
turally permits more oil to be drawn
| into the cylinders. Too high an oil
pressure will waste oil at high rate
| in a modern motor. This may be due
/ to trouble with the relief valve or tt
clogging Of few of the oil outlets.
Such clogging generally can be traced
to the use Of dirty oil or to careless.
ness in adding oil. Thousands OF gal.
! Ions Of oil are wasted annually also be.
cause Of owners making the mistake Of
Gaping the breather pipe.
Save the oil and you save perform
| (Convrirbt 1872 the Russell Service)