The sun., 1916-11-19
IMPORTANT TENDENCIES
IN 1917 CAR CONSTRUCTION
Smaller Bores, More Unit Power Plants and In
creased Use of Thermo-Siphon Circula-
ton Are Notable Changes.

A general survey Of Inc tendencies In
.,,ees and design of the automobile Is
made In the current Issue Of HorseIeSs
,ss. accompanied by complete specihca.
.ons OF all the passenger cars and COM
.,src,al vehicles announced for the 1917
.srket. Last year. II will be remem-
..,sd. says this automobile trade maya
sir. sc outstanding feature Of the sea-
.nal announcements was a wholesale
auction in prices. which brought with
a large increase In the number Of
| rodce In the lower price classes and a
corresponding decrease in the higher
,,.s.es. This movement has not only
entirely ceased. but the price pendulum
sss even begun to swing the other way.
While the lowest price class a not been
.sHcted. II will be observed that there
~ been a marked reduction In the num-
'n.r Of models in the class mex to the
,oves'. from 20 to 17.2 per cent. The
~ Of this class IL more than eQuailed
NJ ealns OF the three classes next above.
There are. therefore. many more models
NV being listed at between $1,000 and
~ OOU imam lnSTe WeAc ihSt year..
The 81, OO0-33. 900 class remains sub
rdoed class, above $4,000. there 10 q
suytber marked decline. The market IL
evidently still gravitating from the
higher toward the moderate priced
rlasser and the pressure of the demand
mas enabled manufacturers Of moderate
nriced cars to raise their price some
shat. the constant advance In the price
AZ nearly all materials and the scarcity
~ ls5or afyording excellent reasons Cor
Inc step.
II Is interesting to study developments
in regard to cylinder numbers. First, II
will be seen that the six cylinder type Ia
we'll holding its own. for while Its per-
csntage is slightly lower than for 1915.
/. Il higher than for. 1916. Tho sum
total Of the percentages Of sight and
Twelve cylinder models is exactly the
ane as u was last year. and the gain
Of the six cylinder class has been wholly
at the expense of the four.
The trend toward smaller cylinders
stu continues. Thus practically SO per
cent. Of all the engines now have a cy-
Under bore Of less than SIS inches, while
lsst year the percentage raj only 37.s
and the previous ear only 10.s. This
4 partly explained by the gain Of the
aY cylinder over the four cylinder
model, and-if we follow the develop
mont over a number Of years back
by the appearance of eight and twelve
Grinder engines. On the other hand,
Il 10 In no small measure due to the
advent OF the high speed engine. Small
bare engines are desirable on account
4 their smoother operation, and small
Engines offer advantages In the way oil
fVduction in total car weight. fuel econ.
smy. tire economy and tag rates.
For the smaller bore cylinders, up e
~ inch, the average stroke bore ratio
y now substantially 1.6. An the bore
Increases the stroke bore ratio decreases
and the average stroke In all Glasses IL
not far from 8 inches. This dimension
Sems TO be limited to Q certain extent
by considerations Of al appearance. fol
when the stroke much exceeds this hg.
us /. is difficult to obtain pleasing bon.
net lines.
Casting all cylinders IN . single bloch
10 now the accepted practice In foui
cylinder engines and In rapidly approach,
ing the point of universality In six cylin.
der construction. This practice has beef
flrthered by h simultaneous change
from integral to detachable cylinder
heads What has retarded the adoption
Il the en- bloc construction. especial!
n SIX cylinder engines. In the past 1,
The dif5cuity OF the core work II thu
heads are integral. Detachable cylinder
heads facilitate the Decentralization %
the cylinders. which makes them an ad
vintage to the user. The facing Of tn.
surfaces of the goint and the provision o
The gasket involve q certain amount o.
expense to the manufacturer which II
at-t.A A. I>.A. .-.l- L..
tssral but with modern methods Of sur
face milling In multiple spindle ma
chimes this item can be reduced to sucl
a low figure that the advantage appar
emily remains with the separate hea,
even In the lowest priced machines. II
The six cylinder class the practice o
grouping h cylinders In pairs, whicl
was for years popular with leadini
manufacturers, shows n decided fallin,
m from about 80 20 10 per cen Thu
only model in this class with singly cas-
CYLINDERS Is the Franklin. and the form
" the cylinder of this air cooled engin,
is sufficient reason why the singly cas-
construction should be retained.
There has been no change in the per
centage Of the L-head type of cylin
der during the last two years. Th'
r-head type has continued to lose ad
Nefehts, thls time 10 the advantage n
the valve In head construction. Thil
latter type has been extensively ad
~'ert.sed by it's now almost exclusive us,
IA racing engines. and some importan
advances ave been made In the desigi
valve operating mechanism for valves
''caied IN the cylinder head. with re
poet to efficient fabrication and cas-.
adjustment There has been consider
"h'' prejudice against his construction
30 Va" pas, on account of suppose
greater noise ~ operation. hut the pro
''tion ~ housings oNer tho valves hai
i"lnn,"d his objection. " iS Also quit
ls'lhi" that another factor responsible