The Lake County times. [volume] (Hammond, Ind.) 1906-1933, 1920-05-24
VALVE SURGERY
KEY To HEALTH
OF YOUR MOTOR


When poppet valves do not function
properly. due to warped heads and like
troubles, bent stems, worn stems, there
Is a considerable falling of i'm The power
developed by the engine. and the owner
Immediately discovers lit in the form OF
poor performance The time honored
method Of testing the compression by
cranung the engine by hand slowly to
determine the relative resistance Of
Tered Is a fairly satisfactory way Of de-
terrninins compression loss, but does not
indicate whore that loss exists.
The owner of a car should bear in
mind that valve heads work in an ex-
tremely hot atmosphere. since the heads
are in the combustion chamber and con
%sequently are exposed IL the flame of
= explosions. hey must. therefore. be
able to withstand the terrific heat with
out warpIng. because if they should
warp the effectiveness Of the valve to
make a perfect Joint with its seat would
at once be destroyed.
The reason. car manufactures state.
that valves are surrounded by adequate
water SPACE IS because they wish to
show that tho valves. being properly
cooled, are not likely to be affected
qIickly by the heat. In some Sin
where proper provision has not been
made for the proper cooling of the
valves the engines give continual trou-
bic from loss of compression. valves
ticking. valves requiring frequent
grinding and mishring due TO irregular
lties in the valve action
only safe way an owner can tell
whether "a valve head is warped or
badly pited or a stem bent or badly car
z~,-a g., p * 1~.--., #En -.f-. --~,---
ii. and measure it. While the compress
sion test is all right to check losses due
10 poor valve seating. 1t must hrst be
determined that there is no leaka ge
e.sewhere. as for example. around Ihe
sylinder head joint or valve plugs. if
such be used. or past poorly fitted pis-
IONS or rings. or due to worn cylinders.
After a valve IS removed by means
ct a valve spring compressor. permitting
the val We seat support 70 pc slipped out.
IT should first BE- carefully cleaned. by
immersion in Kerosene. then wiped with
a clean cloth Examine the face of the
valve for small black spots Place the
valve upright on a level surface and
measure four or hve distances from
head 70 plate This will give you A
good check on the trueness of the head.
A variation that can be measured with
an ordinary rule may be taken as be
ing nough to cause poor valve seating.
hence leakage Of mixture past the valve
when II * closed. A valve with a
warped head should b replaced.
Test the stem for straightness. Place
the stem on a level plate. while the head
If tho valve hangs over the edge of
the plate. The eye can instantly detect
# The stem IS not straight II it is bent
----- ]
4 bent stem may cause the valve To
stick open or 1t also may cause it TO
return to It's seat too slowly. If the
valve stem is straight il should DC
checked for diameter. The best way %
do thls Is first to polish the stem With '
q piece Of emery cloth. and then try it,
N its particular guide. Place itrin tho =.
guide (when the tappet Is air the way
down. and. holding one hand on the
stem and the other on the head. TO force
the valve against its seat, feel for side
play. There should be none percepti-
bic. II the valve stem can he shaken
IL its guide 1t will allow oil TO leak
down and oil to leak IN.
You may notice that there is oil
AL arounr the valve springs and the
tappets and on the side of the engine on
which the valves are located. That oil
Usually comes out through the valve
guides. which. by the way, may them
selves be worn II is possible IN some
cases where detachable guides are used
Is install a new guide to tit the worn
stem. but where tins construction IS not
used q valve with an oversize stem must
ne obtained and htted TO the guide. Tt
should be Just free enouE Oh so it falls to
It's seat after beSng lifted about an inch.
At the same time that the valves are
tested for the defects mentioned the
valve springs should be measured and J
examined A weak spring Is likely TO
cause a lot eff trouble. Place the spring |
IN a level plate and with the eve notice
# it IS out Of shape or smaller than
anv Of the others- Usually you can
stretch and bend the spring so 1t VIII
return 10 its normal shape. but where
not prevent the spring from falling
into almost any position when in use
II a spring is known to be weak be
cause of weakened metal the best thing
10 do is to get q new spring. or as a
temporary measure put a lot of washers
under il to compress it stil1 more. so as
to get a little added pressure.
When the valves are out Of the en-
pne and the heads are badly carbonized
brlnding IS resorted 10 TO make the
19int between face and seat accurate. |
In the shops the grinding is a matter of
a few minutes. because the valve is re-
faced with a special tool and the valve /
seat has a new surface cut with a re-