Abilene weekly reflector. [volume] (Abilene, Kan.) 1888-1935, 1913-09-18
The ValVe-in- the Head Motor
The Reason Why of Bucks Greater Speed and Power

The motor is the most intricate and expensive sim
gle factor in the construction OF an automobile, repre-
senting in round numbers one-quarter OF the cost OF the
finished product. With an electric selt-starter built IN,
it represents even more. So much for mOney-wOrth. In
point of service possibilities and general satisfaction, the
motor represents more nearly Is per cent OF any automo-
bile's value.
Intensely significant, therefore, is this big feature of
Buick construction-the overhead valve motor. Such an
engine, not by theory but by the actual proof of over
100000 Bucks now in use, develops from 10 to 70 per
cent more power than engines of any other type, OF SIM
liar bore and stroke. The Importance of this fact is wor-
thy of a more detailed description.
An internal combustion motor operates by the con-
version of a gas into energy through the medium of COM
bustion. Unless every possible heat unit afforded by the
act Of combustion be conserved, the power stroke will
suffer in direct ratio. Every possible chance for heat
leakage must therefore be eliminated, If full power IS to
be obtained from a gas motor. A theoretically perfect
engine would be one in which an extremely high tempera-
ture could be maintained in the metal cylinders. 1t is
not practical, however, to operate any mechanical de-
vice, especially a motor cylinder, when it's surface is SUI
perheated; consequently some cooling device must be pro-
vided. In the case of an automobile motor, this is gen.
orally done by surrounding the cylinder walls with a hol-
low casing or jacket filled with water, which is kept in
circulation and cools the cylinder walls uniformly. Yet
in such cooling, many of the heat units are necessarily
destroyed and wasted. The smaller the surface of cylin-
der walls which must be cooled, the nearer a motor APP
proaches the ideal.
The amount of cylinder surface in the three types of
motors now in common use may be roughly shown by
comparing them to the letter I, an inverted L and an |.
~ IT'S Is cdlIeu Ii 4 LIcdus IWe ScCOHu IH0 - 1ypC duu
the third the Overhead or Value-in-the- Head motor. In
the last mentioned type the cylinders have no arms or.
pockets; consequently they present the least surface to
the cooling agent and lose, therefore, fewer heat units.
On the other hand, in the en- or "L'' types, where side
pockets are cast on the cylinders for inserting the inlet
and exhaust valves, the combustion chamber is enlarged
by the exact amount of extra surface in these pockets;
and these surfaces must be as perfectly waterjacketed as
the remainder of the cylinder wall. The result is a
greater amount of cooling surface, which is continually
giving up many heat units w~astefully. The straight cylin-
der of the overhead type avoids this, and consequently in
the same size cylinder is able to develop greater power.
Apart from its saving of heat units, the Valvein-the-
Head type of motor has other superiorities. All motors
must depend for their power upon the expansion of the
gas in the cylinders. This expansion is OBJ
tanned by the firing or the burning of the gas under COM
preston, and the rapidity with which this operation is
performed and the greater its completeness, the more
powerful will be the pressure developed against the head
of the piston. It is this pressure of the exploding gas
against the piston head that produces all the power of
automobile motors.
A quick and complete explosion is therefore of prime
One of the first essentials to this is that all
points in the combustion chamber be II brought as nearly