El Paso herald. (El Paso, Tex.) 1901-1931, 1918-05-25

the shape OF the cylinder and the COM
parativs location Of the valves. con-
troll the power output Of the engine.
This is true within limits. but IN max
ing comparison It must be remembered
that IL is hard to get two engines Of
different types OF exactly the same
size and consequently potential power
output While the valve-in-head
cylinder is generally acknowledged 20
be the best type theoretically, 10 would
be perfectly possible to get an L-head.
theoretically the weakest type. TO per
form better than the other. In the sec
oud place differences in performance
are largely academic and well made
engine Of any type viii perform well
enough 70 satisfy the average car
owner
Observation-Disclosures
At the present time the valve-in-
head engine is making rapid strides
into favor with the discriminating
automobile public. It has certain very
real advantages. among which must
be listed the ability TO employ valves
of generous size. This type also per
mits very efficient cooling Of the COM
bustion chamber. But to realize all
these potential advantages TO the ut
most. the cylinder must be correctly
designed and constructed
The materials used IN cylinder con-
struction today are gray iron steel,
semi-steel and aluminium Gray iron IS
BY far the dominant material in this
field. The reasons for this are not
only the general satisfaction given
by the metal. but its relative cheap
ness as compared with its rivals. steel
is so extensive that il can be used
on only the highest priced engines and
at the present aluminium is in much
the same boat After the war when the
price of aluminium drops again, this
material may begin registering gains
~ e-n1 @ aaHH"H
ders has been solved IN almost as
many ways as there are cylinders In
automobile use II used TO be the
custom 10 cast each cylinder separ-
atelv or cast two together. but this
'is no longer the case Cylinders are
still cast in pairs. that is two or them
are integral and these pairs are bolted
together TO form the engine unit, but
it is getting to be the accepted prac-
tice 10 cast four cylinder engines in
blocks and skies are handed IN lle
same way. Fights and twelyes usually
embody blocks Of tours or skies,
though even these may be cast In sin
gle blocks. The block casting has
won its way into favor during the past
few years because Of its cheapness
and also because il has the positive
merit Of rigidity.
Removable Heads.
Cylinders may be still further clas-
sified in accordance with Wnelner
they have fixed or removable heads
In the removable head type, this part
is detachable and is held in place az
the top Of the cylinders by means or
bolts. a gasket being used to make
the Joint tight From the owner, g
point OF view the detachable head is
a distinct advantage. since il gives a
ready access 10 the interior OF the
engine for grinding valves, removing
carbon, etc.
1t is a very common practice 70
cast the cylinder block integral with
the upper half Of the crank case, par
ticularly in the medium and low priced
car classes. and even in some Of the
more expensive makes. This construc-
tiou gives q very rigid crank case and
has other advantage Another de-
velopment Of recent years is the prac-
tice Of casting the inlet and exhaust
manifold in the cylinder block This
ont only simplifies the design over the
old method Of boiling on outside pas
sage. but tends TO heat the fuel on
its way TO the combustion chamber a
decided necessity in these days OF low
grade gasoline.