Hey, Gus!" Joe Clark poked his head
out of his little office in the Model Garage to shout to his partner, "Doc
Wisner is on the phone. He's burned out a bearing or something up on
the bend in the road nearest to Mulberry River. He's up there fishing.
Wants you to tow him in."
Gus Wilson, who took care of the
mechanical work in the establishment, turned away from the car on which he
was working and tossed a wrench into his tool kit.
"Up on Mulberry River, eh? All right,
Joe, tell him I'll be up there right away."
Gus waited until Joe had stepped back
into his office. Then with a sly grin wrinkling the corners of his mouth, he
reached into the bottom of his own car and quickly snaked out a fishing rod
and tackle box, which he slipped under the seat of the tow car.
"Good old Doc!" he murmured, as the
tow car rolled out of the garage. "The fish must be biting today.
It's about time I had a go at them!"
But the smile disappeared from Gus's
face as he rounded the last bend in the road. "Guess Doc really is in
trouble," he muttered, as he pulled up behind a new sedan that had been
driven a little way up a wagon track leading toward the river. A
short, plump man in hip wading boots was bending over the raised hood and
gazing disgustedly at the motor.
"Howdy, Doc," Gus called, "I was
hoping you were fixing things so I could sneak an hour's fishing."
"That's just what I was going to do,
Gus," Wisner grinned, "and then danged if the motor didn't go haywire!
She's burned out a bearing or blown a piston or something. There's a
terrible clank when you start the engine."
"Did it happen suddenly?" Gus asked.
"Sure did," Wisner replied. "I found
the fish were biting fine, so I came back to the car, intending to drive to
that house down the road and phone you. When I stepped on the starter,
the motor roared like a mad bull and I had to stop it by turning off the
ignition. Nearly scared me stiff. But the throttle didn't seem
to be jammed, so I tried it again, and that time the motor started normally.
As soon as I got it going, though I heard a loud clanking noise. I
shut it off right away and walked down to the house. Suppose we get in
a bit of fishing, and then you can tow me in."
"That's a queer one," Gus grunted.
"Motor raced, and now there's a
clanking noise. It might be a burned bearing or a blown piston, all
right, but then what made it race? Let me look at it a minute before
we go down to the river. I'm kind of interested to see what caused
Gus reached into the car's tool
compartment and pulled out the hand crank.
"Now we'll just see about that
piston." He grunted, as he applied the crank and slowly turned the motor
over. The compression seemed uniform on all cylinders. Then he
bounced the crank against compression at several different points, but there
was no trace of a thump.
"No telling whether you've cracked a
skirt off one of the pistons," Gus observed, "but it's a cinch you haven't
busted any piston heads. A little click or clank when you rock it
against compression might come from the valve mechanism, but the fact that
there isn't any noise at all is a pretty good sign that there's no
"Maybe it won't clank now," Wisner
"I wouldn't take a chance," Gus
decided. "It doesn't pay to run a motor if it is making any queer
noises. Anyhow, I wouldn't want to start it without taking a look at
that throttle. Perhaps the butterfly valve has come loose from the
Gus lifted off the air cleaner, and
peered down into the carburetor opening.
"What the Sam Hill is that?" he
growled, as he cautiously inserted a huge finger in the opening and fished
out a thin, rough-edged piece of metal.
Gus turned the air cleaner over and
examined it closely. "Well," he chuckled, "guess we might as well get
in a little fishing, and then I'll tow you in. Here's the trouble.
This inside flange on the air cleaner has broken - the metal must have had a
flaw - and two pieces went down into the carburetor. Here's one of
them. The other jammed the throttle open when it dropped loose, and
then it got through into one of the cylinders. That's what is causing
the clanking noise. I'll have to take the head off to get it out."
"I never could see much sense in that
air-cleaner business," Wisner complained, as the two men headed for the
river bank. "When you get it fixed up, why not leave off the air
cleaner? What's the need for such a gadget, anyway, when most of the
roads are concrete and there isn't any dust to speak off? People don't
have to breathe through an air cleaner, so why should a motor?"
"I'm ashamed of you, Doc," Gus smiled,
as he pulled his fishing rod out of the case and started to put it together.
"Have you forgotten all the little hairs inside your nose? They do
exactly the same job for the air you breathe that the oiled metal filaments
in the air cleaner do for your car's air supply."
The doctor grunted, "Score one for
you, Gus. Of course that's true. Still, I shouldn't think that
the little dust there is in the air these days would do the motor any harm."
"No dust in the air, eh?" Gus
countered. "Then what is all that stuff that settles on your car when
you get it spick-and-span and leave it standing outdoors - even on a
concrete road - for a couple of hours? And if you rub your finger over
the hood or the top of a mudguard, you pick up a lot of fine grit that would
make a pretty good grinding compound if you mixed it with a little oil.
"Another thing," Gus continued,
warming up to his subject, "every time somebody analyzes the carbon that
forms in a motor, he always finds that a large percentage of it is road
dust. Aside from that, the air cleaner acts as a silencer. Take
it off, and the air rushing into the carburetor makes a whishing, sucking,
gurgling sound so loud it'll drown out all the other noises in a car."
At this point in Gus's little talk on
air cleaners, he hooked a big fish. In the ensuing excitement, the
subject was forgotten. It was a lively battle, but Gus finally worked
the fish close to the bank where Wisner was standing.
"Net him quick!" Gus shouted.
"Feels like the hook may let go any second!"
The doctor was just in time, for the
hook snapped loose as the net scooped up the prize.
"Guess we'd better get going now,"
Wisner suggested, "I want to get in touch with my office pretty soon."
When they got back to the Model
Garage, Wisner phoned his office and, as there were no calls, he decided to
stay and watch Gus fix his car.
As he had predicated, Gus found the
piece of metal in one of the cylinders. Fortunately, it had not scored
the wall, so he started to reassemble the head.
"The trouble with this air-cleaner
business," he grumbled, as he brought out a new cleaner and tested to see if
it fitted properly, "is that more than half the air cleaners on the road
today aren't doing what they should.
Just because the air cleaner
ordinarily doesn't give any trouble, most owners neglect them. The oil
gets all dried out, and after that most of the dust goes right through.
"And what's even worse," Gus went on,
"is that some car owners just go on spilling heavy oil into their cleaners
without ever giving them a real cleaning out. After a while, the metal
filaments get so coated with a caked-on mixture of heavy oil and road dust
that they actually cut down the air flow. Then the owner goes around
complaining about what rotten gas mileage he's getting, when the only
trouble that his air cleaner is so clogged it's giving the same effect you'd
get by running with the choke partly closed all the time. A badly
clogged air filter will cut your gas mileage sometimes as much as three or
four miles to the gallon - and that's a mighty big waste."
"I know the instruction book says to
clean it out with gasoline and re-oil it," Wisner commented, "but that
strikes me as a pretty messy job. Can't you blow the dirt out with air
pressure some way?"
"You can't get it really clean with
air pressure," Gus replied. "And the job of cleaning isn't so messy if
you go about it the right way. Get yourself a couple of cans big
enough to take the air cleaner, and have one of them about twice as deep as
the air cleaner is high. Have covers for both of the cans. Put
the air cleaner in the shorter can and pour in enough plain gasoline to
cover it. If you want to play safe and have no worries about fire, use
one of the standard non burning dry-cleaning fluids instead of gasoline. Let
the air cleaner stand in this fluid for five minutes or so and then swish it
up and down a couple of times to dislodge all the dirt.
"In the deep can," Gus continued, "put
enough light oil to cover the air filter. The lighter the oil the
better. Winter engine oil - S, A. E. 20, or even a lower viscosity, is
about right. Dunk the air cleaner in the oil and then, with a piece of
string and a short stick, hang it in the upper part of the can overnight so
as to let all the excess oil drain away. If you're in a hurry, you can
cut the draining time to ten minutes or so, because what little oil runs out
after that won't have any effect on the motor.
"It'll take quite a while before the
cleaning fluid gets so dirty that it won't take all the dirt out of the air
cleaner," Gus continued, "and you'll use so little of the light oil that
you'll hardly notice it."
"Sounds like a cinch that way," Wisner
agreed, "only I think I'll tie the string onto the air cleaner before I
start. Then I won't have to get my hands in either the cleaning fluid
or the oil. How often should you do the job?"
"The instruction books usually say
every 1,000 miles or so," Gus replied, as he fastened the air cleaner in
place and started to put his tools away, "but, of course, it really depends
on how much dust you run into, and not on how far you drive. If you're
driving in heavy traffic, on roads with dirt shoulders, you pick up dust
fifteen or twenty times faster than you do if you drive over the same roads
with no traffic."
"Suppose I give the air cleaner a
treatment every 2,000 miles if the going is mostly on concrete without much
traffic, and cut the intervals down to as little as 500 miles if the traffic
is heavy and there is a lot of dust?"
"That's reasonable, Doc," said Gus, as
his friend climbed in and started the motor.
Joe Clark, who had stepped out of his
office just before Wisner drove away, was sniffing the air suspiciously.
"I smell fish," he grinned, as he
picked up the leaf-wrapped trophy and examined it admiringly. "You old
fraud! Now I suppose you'll tell me you pulled this out of Doc
Wisner's motor, too!"