The news scimitar. (Memphis, Tenn.) 1907-1926, 1920-02-17

The following are some Of the on
moncr valve and valve gear troubles.
10 which the motor a engine Is sub
1nct. Reduced and delayed onepinC
This arises from too much clearance or
lost motion in the valve cear. ga h
the valve does not begin 10 open as
soon as the push rod hrrins 10 he Tatsod
by IT'S cam, hut only after the push
rod has risen enough 10 tate up the
loosrnCga among the narts. The result
Is that tho valve opening is late. but Its
closing IL on time, thus shortening the
duration Of OpeninC and moreover the
valve never fully OPENS, with resultant
loss In power. BEFORE the valve gear
becomes extremely loose. through long
continued wear. Il becomes very polsy
and when there Is a noticeable tapping
or clicking noise. II Is best 10 readjusi
the valve gear. So as TO eliminate al
unnecessary l~OosenCsS Badly worn
cams also cause reduced valve Cnenlnc,
Valve rear too tightly adjusted. This
prevents the valves from ever fully
seating. especially when an engine Is
hot and is the reverse Of he trouble
lust mentioned It is likely to be found
only after an attempt has been made
10 correct valve gear lOoseness and the
adjustment has been overdone, When
an intake valve Is slightly holding omen,
from this cause, an engine will fail to
idle slowly II may hackflre and will
give reduced puwer The obvious RENE
DIV is to readjust the parts so that there
shall he a very slight slack or clearance
In the valve operating gear,
Failure Of Valves to Close-A valve
may fair entirely to close. or IL may
close so slugEishly that. at high speed
Il does not seat In time TO fulfill its
purpose. This may either he due to
the spring being weak or broken or by
friction IN the valve gear. The valve
stem may he dry. slightly bent or
gummed with ~carbonized oil or the
push-rud may stick In its guide, When
a valve fails to seat. the engine lacks
power, misses explosions and some
times 'pops'' In the carburetor. II a
spring Is thought to be weak. stiffen Il
a little by pryinE It's coils apart with
a s~crewdriver, while the engine Is run-
ming and. " this speeds the engine up,
replace the spring, A valve stem that
sticks in It's guide can usually be made
10 work by scraping II clean. polishing
the stem le~nEthwise with fine emery
cloth and keeping IL oiled.
Lcaky valves cause loss OF fuel,
through It's escape unhurned and be-
cause OF the low compression attained
In the cylinders. A leAky valve Is indi-
Gated in a cylinder (Which has a tight
p%istonl, when this cylinder. when
crankedi by hand through Its compress
sion stroke, offers a rapidly decreasing
resistance TO the cranking effort. II
the valves are we'll sealed, the piston
can be forced up again and again on the
am compression stroke against the
springy resistance Of the confined gas
and. when this Is the case. the valves
are tight and do not require regrindlng.
Even though they do leak, IL may be
only because their faces or their seats
have carbon on them and. when this Is
carefully scraped off, they may he found
TO be tight, II grinding be found nee
essary. II should be done as lightly AS
possible to give results. or the valves
will soon have TO be reseated. Gem
eral mistiming OF the valves Is likely
10 be occasioned only by incorrect
meshing u the camshaft gears, when a
car Is carelcssly assembled after over
hauling.
Even "a very slight error In setting the
gears viii utterly prevent satisfactory
engine Liberation, but as every instruc-
ton book tells at what angles from the
dead centers the inlets and exhausts
should open n close. Il is easy to
find out whether the setting is correct.
When valves are taken out, they should
be inspected to see that their stems
have not worn too loose In their guides,
for II the inlets are very loose, air leaks
into the intake will occur. preventing
regular running at low speeds. II the
eNhauSts are In this condition, there
will be unusual exhaust noises and
burning and ~carbontzing of the stems.
Oversize valve stems or new valve
guide h%ushings are the remedies for
this trouble,
l., +, W asks; Is there any arrange.