Audubon County journal. (Exira, Iowa) 1884-1993, 1918-06-20
Cleveland Auto School Head
Gives Its Purpose, construc-
ton and Troubles.
cLOGGlNG 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-
fer. what care does it require and
to what troubles is it subject are ques-
lions frequently asked Of Clyde 81.
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-s
haust valve at high pressure and
the resulting noise is disagreeable
unless it is muffled.
It is necessary to reduce the pres
sure from each explosion and to allow
the gas to escape SO that a great deal
Of its force is dissipated and its dis
jointed nature completely changed.
The gas then passes out quietly with
only a slight pulsation 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 anticipates 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 it
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 muffier In a
steady. quiet manner.
Let Muffier Alone.
The care Of the muffier 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 miss
| 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 1t in many 10
calities. If the sound Of the exhaust
is not sufficiently loud it may be In
! creased by retarding the spark and
opening the throttle part way. The
sound Of each cylinder will then be
brought ont distinctly and any weak
ness will be noticed Immediately.
About the only trouble to which the
muller is subject is that it becomes
i clogged with SCOT. This may be caused
by too rich a mixture from the car
buretor, indicated by black smoke from
j the exhaust, or 1t may be caused BY
oil working up on top of the pistons
4 giving the blush white smoke char
/ acteristic Of too much lubricant.
Carbon Clogs Muffler.
5. 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 81
helps to clog. In order to clean 1t,
must be taken apart and all the car
bon deposits removed. II the small
n holes are closed with SCOT they mus
be reamed out with three-cOrnere,
| file or bearing scraper. The parts ar
4 then reassembled carefully and re
placed on the car.
i 1t is easy to tell if the muffler /
clogged where there is cutout. Rul
the machine up a fairly steep hill. u
the car speeds up with the cutout Ope
it shows that the muller is clogged.
A well designed silencer should no
cut down the power Of the engin
more than per cent. This difference
will hardly be noticeable on an OF
binary hill. So the fact that the ca
slows down would indicate back pres
sure due to clogging.
Get Car out Of Mud.