The Knoxville independent. [volume] (Knoxville, Tenn.) 1894-current, 1918-07-06
MUFFLER Care is
IMPORTANT Item
Cleveland Auto School Head
Gives Its Purpose, construc-
ton and Troubles.
CLOGGING IS DUE TO SCOT
May Be Caused by Too Rich a Mix.
ture From carburetor, Indicated
by Black Smoke From Exhaust
Best to Let 1t Alone.

What is the purpose Of the muf
fier, what care does It require and
to what troubles Is 1t subject are ques
tons frequently asked of Clyde H
Pratt, president of the Cleveland Au,
tomobile school.
The purpose Of the muffler, he says
is to diminish the noise of the ex
haust. The gas escapes from the ex.
haust valve at high pressure and
the resulting noise Is disagreeable
unless 1t Is muffled.
1t is necessary to reduce the pres.
sure from each explosion and to allow
the gas to escape so that great deal
OF its force is dissipated and it's dis
jointed nature completely changed.
The gas then passes out quietly with
only a slight pulsati0n or throbbing.
The methods by which this is
brought about are simple. A gas pass
ing along an ordinary pipe would be
slowed down and spread out. But this
arrangement would require too long a
pipe. So Earthquakes are used to
make the gas turn corners and force
its way through small holes in the
plates.
In some mufflers the gas enters an
expansion chamber. All this time 1t
is losing heat and so contracting and
thus 1t slows down more and more.
The final effect Is, as stated to have
the gas issue from the muller in
steady, quiet manner.
Let Muffer Alone.
The care Of the muffler is to leave
1t alone until 1t becomes clogged. It
does it's work without attention and
requires nothing from the driver. The
only time we think Of 1t is when we
wish to find out if the engine is MISC
ing explosions. Then we cut out the
muller and listen to the sound of the
exhaust.
Do this cautiously on the road, as
there are laws against it in many To-
calities. If the sound Of the exhaust
is not sufficiently loud 1t may be in
creased by retarding the spark and
opening the throttle part way. The
sound of each cylinder will then be
brought out distinctly and any weak
ness will be noticed Immediately.
About the only trouble to which the
muffier is subject is that it becomes
clogged with SCOT. This may be caused
by too rich mixture from the car
buretor, indicated by black smoke from
the exhaust, or it may be caused by
oil working up on top Of the pistons,
giving the blush white smoke char
acteristic Of too much lubricant.
Carbon Clogs MuffIer.
Another cause is where the carbon
has been scraped loose from the cylin-
ders, but allowed to fall on the piston.
This is carried into the muller, and so
helps to clog. In order to clean it, it
must be taken apart and all the car
bon deposits removed. If the small
holes are closed with SCOT they must
be reamed out with a three-cornered
file or bearing scraper. The parts are
then reassembled carefully and re-
placed on the car.
1t is easy to tell if the muller is
clogged where there is a cutout. Run
the machine up a fairly steep hill. If
the car speeds up with the cutout open
1t shows that the muller is clogged.
A well designed silencer should not
cut down the power Of the engine
more than per cent. This difference
will hardly be noticeable on an or
binary hill. So the fact that the car
slows down would indicate back pres
sure due to clogging.