Tulsa daily world. [volume] (Tulsa, Indian Territory [Okla.]) 1905-1919, 1915-08-01
WHAT To DO WHEN
YOUR ENGINE KNOCKS


NV '''''N W N'''
/ Knocking in an engine is one of the
hardest things Tor even the expert
enced repairman to identify because
most OF the internal noises, while they
/ Indicate that something is not right
are so nearly alike in character that il
| is most difficult To distinguish the
cause Of one from another.
1t Is only possible to diagnose motor
knocks in a sort of general way for
| even though to the experienced ear
certain knocking may appear TO be
caused by too advanced spark, for
instance, it may in reality he caused
by loose rod bearing or a shaft bear
ing. But the more experience a man
gets with the particular motor he is
driving. the easier 1t is for him to tell
Just what any kind of knock in that
engine results from.
Some of the knocks, of course, are
easier to distinguish than others. For
instance, il is usually possible to tell
a loose piston knock from the others.
This is commonly called piston slap.
General Causes of knocks
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Tho snead nf tba enainn 49, ,ho
charge is ignited before compression
is completed. the firing of the charge
cxerting q sudden downward force
upon the piston before it should re-
ceive that downward impulse. The
remedy Is very simple. Pull the spark
! lever down lower on the quadrant
until the knocking stops, or remove
!
out the clutch, or slow down the
motor.
The general indication of a carbon
| knock is fairly clear and hollow
pounding which is specially evident
When the engine is not and when on
hard pull, such as through deep
sand or up good grade Carbon
/ knocking is due to excessive carbon
/ deposits on cylinder walls, piston
heads, etc. The carbon particles be-
come red hot due to the intense heat
within the combustion chamber ana
they ignite the charge before com
preston is completed and the piston
is In position for ignition to take
| place. In other words, it is a pre-
| ignition knock. Improperly adjusted
carbureters which send too rich mix
| tures to the cylinders, poor lubriCat-
| ing oil and excessive use OF oil are
the three main factors in the follow
ing Of carbon incrustations
Carbon Causes Knocking.
No., oh,,io,,s rooso,,s oort,,
,.i, t li,.i..G1a ,ti.ilI, uo,
knock. although IL is somewhat more
muffled Suppose the same compar-
isOn to be made in the initiating Of a
carbon knock as already made for the
spark knock only, instead of wrap
|
newspaper, half-dozen thicknesses
are used between 1t and the telephone
body to initiate the sound
A lose connecting-rod bearing on
the crankshaft gives out noise every
time the piston to which it is CON
nectcd receives the explosive impulse
Slpposing a light tapping Is done with
hammer against a piece of steel.
There is a clear ring to the sound,
which In the case of the motor is
somewhat hampened because it is
within. If the tapping of the ham
mer on the steel is done at distance
the closest imitation to the rod knock
is brought out.
This particular type OF knocking is
especially evident when the engine is
.unning without load, or idling. II be
comes quite distinct when coasting
down a grade or when the motor is
speeded up and the throttle suddenly
closed. This is chiefly because the
other noises of the car are less accen-
tuated at such times, making it easier
to hear the clear metallic knock.
Worn Rearing Means Adjustment
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