The Washington herald., 1919-02-16
HOW TO REMOVE
ENGINE NOISES
Means to Overcome the
J Greater Sources of Rat
tling Discussed.

Noisy operation is the bette noir OF
silence is impossible to be attained in
any piece of machinery, especially in a
vehicle traversing the roads under its
achieve IA reasonable freedom from
loud noise by little intelligent under
standing and care.
The engine is the seat of the greater
part of the really offensive noises that
sometimes beset the modern automo-
bile. The commonest noises arising
from the engine are valve clicks and
slaps. These may be distinguished by
the regular rhythm of their recur-
renee. The cause may be too great a
clearance between the valve stem and
the tappet, or in the case of overhead
valves, the clearance between the lift
er and the push rod may be to blame.
The remedy for this condition is the
reduction of the clearance and this ad-
justment should be made while the
engine is hot This is necessary be-
cause of the expansion of metal when
heated. In which condition the valves
operate. 4, II adjustments were made
When the metal was cold, they would
not be correct after the parts had be-
come heated with running.
Occasionally, however, clicking in
the valve mechanism is caused by a
litter being loose in its guide. To To-
cate thss trouble the litter assembly
Will have to De removed aud in the
main a worn litter must be replaced.
Certain designs of guides are such
that the guide may be sprung slight
ly. SO that 1t will grip the litter
tighter. remedying the trouble.
Another location for trouble OF this
kind is at the cam. between which and
its follower there may be too much
clearance. Fitting new followers usu-
ally has a beneficial effect here. Worn
valve stems or guides will produce
| noise. Removal OF the springs will en-
able conditions at this point to be de-
termined. There should be no play OF
the stem sideways in its guide and II
investigation discloses play. bushing
should be fitted to the guide or else a
valve with an oversize stem must be
installed.
The valve mechanism in an overhead
valve system normally develops more
noise than does an ordinary L-head
engines valves. Systematic and ade-
quate fabrication will do much TO
minimize noise here. Occasionally
side-play develops in the rocker arms
with a slap as the result. A worn arm
bearing will make trouble. which may
be cured by fitting an oversize bushlns
in the rocker arm.
While the valves are the commonest
| locations OF undue noise. they are not
at all the sole seats OF trouble in the
engine. The bearings in most engines
are made of soft metal. which must be
kept Copiously fabricated or II burns,
becomes tiattened and a knock results.
The ordinary remedy for this trouble
/ is to take up the play by removing the
Shin between the two halves OF the
part or else by trimming the metal on
the removable part Care must he
taken in performing this operation to
see that the bearing touches the shaft
all around. without being too tight.
/ In fitting bearings the utmost care
must be taken to avoid throwing the
shaft out of alignment and this condi-
tion is particularly like;y 10 occur
when one bearing is. fitted without
reference to the others. In unit pow
er plant construction if the shaft is
thrown out of Alignment. one OF the
gears in the transmission is sure TO
operation ensues.
Another source or bcaunG knock is
the fianses of the crankshaft bearings.
which are tiattened bv Crankshaft
thrust. In this case il docs not pay
to Try 10 fix the Old bearing fanges.
1t is better to get q now bearing.
Play frequently develops in the
upper rod bearing ana very often
+ the motor car owner blames
the lower rod or crankshafi
bearing for the trouble. On many OF
the cheaper cars there is no bushing
at the top OF the rod, while in some
others a bronze bushing will be in
stalled to take up the wear When
there is no bushiny, a new piston pin
will have to be fitted. or if the piston
bosses are worn eccentric. it may
mean a new piston or the installation
of n bushing.
When the piston or cylinder is worn.
it results in a knock that is much ike
the sound that comes from pre-igni-
ton. If this trouble is not severe it
may be cured by fittinE new piston
rings. On the other hand severe
case may call for the installation of a
complete new set of pistons. When the
cylinder block has worn in a slight
oval shape. it may be reOored and
fitted with oversize p:stons. which
makes 1t racticaIly a new block.
Timing gear or chain noises are diff
cult to cure. In certain makes OF
silent chains an adjustment is pro-
vided to take up slack. but where no
such provision IS made the chain must
be shortened by taking out n link or
else a new chain must be installed. II
chain noise becomes chronic. the car
owner will do well to consult a service
station, where an idlcr may be in
stalled to take up slack.
One of the commOnest of all knocks
is that due to pre-ignitiOn. This may
be caused by carbon, too great an adj
vance of the spark, poor timing, over
heating, overlooking of the engine and
incorrect mixture and the greatest of
these is carbon. In every case the
charge explodes too soon, not giving
the piston time to reach the top of its
journey and the result is that it is
thrust against the side of the cylinder.
producing a knock. The only way to
cure this noise lis to determine the
cause by process of elimination and
then do away with the cause.
Transmission noises are not at all
uncommon. When one of the shafts is
thrown out of alignment by reason of
a worn bearing or a binding gear,
noise is bound to result. Sometimes
the transmission case itself is out OF
true, so that both shafts are thrown
out of alignment. Very often gear
will be broken because of shaft mis-
alignment and the owner has q new
one installed. This. however, does not
cure the cause'of the breakage which
is misalignment and a second accident