San Antonio light. [volume] (San Antonio, Tex.) 1911-1993, 1923-04-08

| mas Deen the CauSt Oh muCh Snbih
trouble. So-called blowbys, on-pumT
ing and kindred troubles are eliminat
ed to a. large degree By the more care
full manufacture.
Engine forms of the overhead
valve type have increased, and tn
L-head construction has lost some.
per cent There is hardly good rea
son Tor this in view of the recent.
discovered advantage of the L-head
Even though the overhead is acknowl
edged TO be noisier than the I-heaS
and noise is still a bugbear Of en-
gineers-the overhead engine persists
in gaining. l hardly believe this VII
continue unless air cooling comes If
with a rush and this is for the III,
ture. Considering the production OF
cars and not the different models the
IIrhead has the field to istelf with
Ford, Dodge, Overland, Hupmoolle,
all three Studebakers, all the Continen-
| tai engines, Maxwell and Hudson, as
adherents of the L-head type.
One of the engineering studies which
have helped considerably 10 make driv-
ing pleasurable is that of balance. This
concerns every moving part of the en-
CINE, but principally the crankshat
and the pistons. In all engines the
crankshaft at some time or other de-
fleets (bends) and this change in
shape causes the parts ATTACHED TO II
TO be pulled or pushed out of their
normal positions. These changes OF
position and shape cause vibrations TO
set un. They are destructive of bear.
ings, reduce power and increase fuel
consumption. The four-cylinder en-
CINE vibrates more than the six, no
matter how the design is altered, but
some tours have been "smocthed out
in excellent fashion by increasing the
stiffness of the shaft or by fitting
more bearings and also by using alum
mum pistons.
Adopt Larger Shaft.
1t is agreed that The larger the shaft
diameter the sitter it becomes and
the more likely it is to withstand
stresses tending TO bend it. Also the
more bearing supports Used the less
the tendency for the shaft to bow be-
tween bearings. One engineer states
that with the proper crankshaft de-
sign and correct oiling system no more
than two bearings are needed, and
he has produced a two-bearing six of
remarkably smooth running 10 prove
il. There are few who agree that this
two-bearing six always will run
smoothly after bearing wear has oc-
CURED or afte: it has been repaired
and the shaft returned TO position
out of alignment, q condition quite
easy TO get with two bearings. Two
very large producers of four-cylinder
cars have found il necessary to use
aluminium pistons to get more smooth
ness.
One manufacturer of four Gard
ner) has designed a fie-bearing en-
CINE to get further smoothness. In
the big production tours of low price
vibration comes about not alone be-
cause of the light shafts and heavy
pistons but also because of the I'M
eveness Of size of the combustion
chambers, so that one cylinder will
fire with more force than another.
Continental engines for passenger
cars are now nearly all four-bearing
skies and they are remarkably smooth
for Reproduction jobs. This type
of engine is used Oh more than forty
chassis, while only about thirty use
three-bearing skies. Ten four-cylinder
jobs have two-bearings and twice that
number have three-bearings. The
Fights are nearly all three-bearing
two are fiye-bearing.
Reduction o. Noise.
Engine quietness is an absolute es-
sential and every engineer is watch
ing for ways to reduce noise. In any
engine the greatest l.Oise is made by
the timing drive or front end" De-
velopment here has been somewhat
odd. A number Of years ago we
had strsight-tooth spur gearing, which
was very noisy, and so the silent
chain was introduced; but chain trou-
bles were so many that engineers
returned to the gear drives to further
develop them. Then came helical gear
ing, and this was improved upon By
using cloth gears and composition
types in mesh with steel or bronze. |
This gave fairly quiet drive, but in |
big production extreme care cannot |
be taken, especially in assembling, |
and this results in an occasional run |
of noisy front ends.
Perhaps many readers who drive |
cars have heard certain makes of |
cars with "howling" engin. gears. |
This is incurable except by changing |
the whole set Of gears and doing the |
assembling carefully. 1t was argued |
that the silent chain front end was
quiet to begin with and remained |
quiet, and that no doubt il could be |
developed so that the trouble from
chain stretch could be overcome. This |
has been done in the new forms Of |
chain with automatic adjustment or
with manual adjustment that is quick |
and easy TO make. The automatic has |
worked out very well. IL it continues
to show such good results, we may
look to see practically the whole in
dustry go to the silent chain 'front.' |
end drive. Continental engines for |
nearly all cars now use this form, Jor-
dan, / believe, being the man who |
insisted upon Continental adopting |
it. 1t was one of the most progress
sive moves ever made by large en-
gine manufacturer.
Little CarburetOr DEVELOPMENT.
Carburetors are at a standstill with
respect to development. A big adj
vance will come when more manufac- |
turers follow the examples of Frank
lin and Rickenbacker in fitting air |
cleaners to the carbIretors. The |
cleaner is comparatively inexpensive,
and even though the present forms
are not all to be desired, they do |
q ornnt arnnnnf Of nriftr mn [