The Devils Lake world and inter-ocean. (Devils Lake, N.D.) 1915-1920, 1915-04-01

OF gas.lint >sp'T am. ".a:c r il, thus din: p
ishing the force of the next explosion
"ln an T. or "T' head motor, these gases,
to get out. have to turn corners, as it were.
they have to take a roundabout course in
getting out. They must go first to the
valve chambers and thence to the outlet,
or as We say, tine exhaust valve Invariably
IN these types OF motors, a portion of these
gases fails to get out. The valve opens for
only the smallest fraction of a second-so
quickly that you couldn't begin to see it
with the naked eye-and some of the gas
gets left every time.
But these gases do not get left 1;
vaive-in head motor. The exhaust va ave,
yon know, is directly in the top of the cylin-
der, just like the wirdaw we smoke of was
directly at the head of the hallway. Con-
sequently when the piston starts it's upward
stroke these gases take a straight shoot for
the opening. No corners to turn. No pro-
%]ectlons to stop them. No %crannies or pock-
cts to retard their flight. They make a
straight. hcadleng dive through the exhaust
valve.
This means, among other things, that in
a valve-in-head motor the cylinders are al
ways clean In an IL or T' type motor it
is Impossible to make the insides of the
valve chambers or pockets smooth. There
are little projections and roughnesses and
these catch and hold carbon deposits. And
then, when the motor gets to running rapid-
", these deposits become heated. They get
red hot and thus ignite the ncominc charp-
es Of gasoline vapor before it is compressed
IbIc rror =, ,,~1,Jol l-r-. -.
Which means that it is burned without any
resultant power. This is the condition we
speak Of as pre-ignition. You never have
pre-lgnition in a valve-in-head motor.
Nov there's one other vital thing I
meant to tell you a bout a minute ago when
we were talking about the explosion of the
gas III the cylinder. All automobile men
KNOW th2t for best results it is necessary
to have 4 quick and complete explosion. To
get this it is necessary to nave your spark
plug as near the gas as possible. In an IL
or + type motor, you can readily see, the
11ame has to travel a great deal farther than
IN a vaive-in]head, for the simple reason
that the diameter of the combustion cham
Der IS greater. In a vaive-in-iead motor
this diameter is simply the diameter Of the
cylinder itself, whereas in the other two
types the tame has to travel to the far
corners Of the valve chambers, or pockets.
That this is a vital matter is shown by
the TACT that some makers Of 'T' head mo-
tors provide two sets Of spark plugs. one
for each side Of the cylinder. This is mani
testify a makeshift effort to get around tho
obvious disadvantages of a H' head r2oJor.
winch is the least efficient Of the throc t~pes
An automobile motor is q heat engine.
A theoretically perfect motor would be one
IN winch an extremely high teaa7,eratxre
could be maintained in the metal cylinders.
1t Is not practical, however, to operate an
automobile motor with it's cylinder surfaces
sufefi1ealeo, consequently a cooling device
IS provided. This is accomplished by having
t'e cylinder walls surrounded by a hollow
Jacket "mch is kept full Of circulatinr
water. In this cooling a number of heat
units are necessarily wasted and DESTROYED
oot Inc smaller the surface of the cylinder
walls to DC cooled the greattr the efficiency
OF the motor. In the t. and "T' tvpes. with
thelr side pockets cast into the cylinders for
the insertion of the inlet and exhaust valves.
the combustion chamber is enlarged bv the
exact amount of extra surface in these
pockets, and these pockets must be as ner.
1ectly water jacketed as the remainder of
the cylinder wall. The result is 4 greater
amount Of cooling surface and the conse-
qucnt greater loss of heat units.
The vaive-in-head motor has no va,ve
Chambers, or pockets, consequently it pre-
sents less surface to the cooling agent and
therefore loses fewer heat units. That is
why the valve-in-head cylinder will develon
more power than the II or "v t,ne of +ba
same size.
Now wish to thank you, ladies and
gentlemen, for your kind attention. and T
trust ="
Just one minute, Mr.. MARI. Your ex-
plantation of the valve-in-head certainly is
1ndlsputabfe, but you haven't told US, since
the Valve-ln-head motor is manifestly the
BEST why the other companies stick to The
T. and TT types"
Ina IS an easy question to answer. The
other types are cheapest to manufacture. for
one thing. Another reason is that some man
ufacturers, after boasting of their II or IT.
type motors for years hate to acknowledge
that they have been wrong Having devel-
oped the L and IT. motors to the highest
degree attainable, they dislike to admit that
no further progress, is possible with those
types. they hesitate, also, to re-equip their
factories, go to the great expnse of "a