1938 Cadillac V16 - GM Heritage Center

much shorter and more compact. Given two engines of
equal cubic inch displacement, the straight eight crankshaft
must be longer than the V-8 crankshaft. The V-8
crankshaft, being short and of large diameter, is much
better able to withstand stresses imposed upon it by
explosive forces of the engine and centrifugal forces set
up by rapid crankshaft revolutions. This is an additional
factor in longer life and greater smoothness.
Power forces react upon every crankshaft causing a
rapid, alternate twisting first in one direction, then in
another. This causes torsional vibration. The short,
rigid Cadillac or LaSalle V-8 crankshaft is but negligibly
affected by these twisting forces while the long shafts
of the straight eight engines are seriously affected. This
may be demonstrated with an ordinary desk ruler.
One-half Ruler Twist Full Ruler Twist
First, hold one-half the ruler's length and twist in
opposite directions with each hand. Note how much resistance
is offered to the twisting force. Now try the
same procedure, using all the ruler's length. This
demonstrates the effect of forces developed in a straight
eight engine upon the crankshaft.
At high speeds, explosive forces within any engine
tend to make the crankshaft bend. Again, the short
ruggedness of the V-8 crankshaft resists this bending
tendency to a far greater extent than is possible with
a long, thin straight eight crankshaft. To demon-
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