Los Angeles herald., 1909-06-27
PRO AND CON AS
TO GAS ENGINES
GAIN AND LOSS IN OFFSET
CYLINDERS EXPLAINED
LIGHTWEIGHT POWER sUPPLlER
is PROVED PRACTICABLE
Cars Produced by Members of Auto
Manufacturers Association Re-
veal Comparative Uniform
ity of Designs
BY coKER F. CLARKsoN

BY COKER f. CLARKsoN
Association of Licensed Automobile Manu-
facturers.
NEW YORK, June 19,-The inven-
ton and development of the gasoline
automobile has brought about the evo-
luton of a gas engine which dlifers
from the gas engine of the stationary
type in as marked degree as the latter
differs from the steam engine. Ihough
a dozen years ago the stationary gas
engine designer would have ridiculed
the idea of successfully producing a
gas engine weighing less than ten
pounds per horsepower developed, this,
and more, has now been accomplished.
1t is futile to expect that automoblle
engineers will ever be thoroughly in
accord on subject involving so many
opportunities for detail differences as
automobile motor design, though of
course years of experience have re-
suited in a type of construction fol-
lowed so closely in such larger num-
Der of instances as to warrant being
termed standard practice in this re-
spect Whether taken singly or coll
lectively, the cars produced by the
members of the Association of Licensed
Automobile Manufacturers reveal more
accord than difference in points of de-
sign.
The ordinary way of placing auto
mobile engine cylinders with relation to
the crank shaft (whence. of course, the
power is taken Off is medially over or
opposite the axis of the crank shaft.
But for years-several years in some
instances-sOme cars have mad GYM
ders offset with relation to their crank
shaft; that is, in a position wherein the
center line of the cylinder or cylinders
is not opposite, but to one side of the
axis of the crank shaft.
Position of Cylinder
This difference in practice raises
very interesting and much discussed
subject. 1t has been said that mas
much as a gasoline motor crank shaft
revolves in only one direction, it is mere
common sense to place the cylinders in
such a position that the pistons Will
transmit the power impulses to the
crank shaft most effectively; that is,
offset so that the maximum force or eN-
plosion is delivered on the piston when
the crank is past the top vertical CEN
ter line, and therefore in the best pc
sition to receive it, and the pressure on
the cylinder wall during fifteen to
thirty degrees of the firing stroke is,
owing to the reduction of side thrust,
diminished.
While this statement may be true,
it is apt to be misleading, and in any
event is not the only consideration.
There are very positive advocates both
for and against offset cylinders. Among
the advantages claimed for offsetting
are shorter connecting rods, reduced
wear, lighter construction, reduced
friction between the pistons and CYL
inders on the power stroke, more dl-
rect turning effect on the crank shaft,
less likelihood of knocking motor,
less shock on the engine bearings, less
overall motor height necessary, greater
motor f1exibility and appreciable in
crease in power.
Say Wear Is Greater
On the other hand, it is said by those
who prefer the construction wherein
the cylinders are placed medially OPP
posite the crank shaft that the claimed
advantages of reduced side thrust on
the power stroke and more direct turn
ing effect on the crank shaft have not
much more than a theoretical value.
It is also contended that i'm T-head
motors with their two cam shafts, Off
set cylinders involve a complication
desirable to avoid. And per contra
statement above that knocks are more
common and wear is greater than in
the usual type of engine. Further, 1t
is said that the offset becomse less
advantageous at high engine speeds.
Perhaps the most commonly advanced
argument against offset cylinders is
that the engine is thrown out Of bal
ance when they are used.
The controversy comes down to these
two general positions, namely: On the
one hand, that in properly proportioned
design it is unnecessary to offset cyl
inders in order to take care of the al
legged counterbalancing advantage OF
doing so, less side thrust on cylinder
walls on the power stroke, etc; and
on the other hand, that if an engine
with offset cylinders is made as it
should be certain distinct advantages
which have been suggested above are
gained and clearly counterbalance any
consequent disadvantages.