One sizzling hot summer evening while Gus
Wilson and Joe Clark were working late on a rush job, a year old
eight-cylinder sedan drew up in front of the Model Garage and the owner
"Howdy, gentlemen," he
drawled as he strolled over to the garagemen. "I see you-all are still
making hay though the sun is down. Could I impose on your good nature long
enough to have you look over my motor?"
"Be with you in a jiffy,
Colonel Marrold," Gus replied as he finished tightening a bolt and reached
for a clean piece of waste. "What seems to be the trouble?"
The Colonel's brow wrinkled
in a puzzled frown as he twisted the end of his snow-white mustache.
"I can show you what it does," he said, "but I haven't any notion of what's
wrong. Old Betsy, that was my old car, She, couldn't fool me with her
whims; but this newfangled youngster has me guessing for sure."
Gus smiled, for Colonel
Marrold at the wheel of old "Betsy," a huge six-cylinder bus of ancient
vintage, had been a familiar sight around that section for many years.
"I had it all figured out it
was dirt in the carburetor," Colonel Marrold continued as he climbed in and
prepared to start the motor. "The pesky engine misses fire as old
Betsy did when something got in the carburetor. I cleaned it twice and
that didn't do any good. So then I cleaned all the spark plugs and
touched up the breaker points. That used to make old Betsy run like a
The Colonel stepped on the
starter pedal and the motor, being warm, started at once, but it did not
settle down to a steady purr. The cylinders missed fire irregularly
and there was a peculiar roughness in the way it ran.
"Runs sort of shiftless,"
Colonel Marrold complained. "Kind of like a row of soldiers, some of 'em
stumbling and not keeping in line. Only if it was soldiers, Suh, I
could have the top sergeant take 'em in hand!"
"You've hit the nail on the
head without knowing it, Colonel," said Gus as he reached over and pulled
the switch that cut off all the lights outside the garage.
"Look at that," he
added, raising the hood of the car on the distributor side.
In the dim light from the
street lamp some distance away, the space under the hood looked like a chunk
of utter blackness in the general gloom. Here and there tiny sparks
flashed at irregular intervals and each flash was accompanied by a sharp but
faint snap that was barely audible above the hum of the motor.
exclaimed the Colonel in amazement. "What in tarnation is going on
Gus snapped on the lights.
"Your spark plug wiring is shot," he said. "It's leaking like a sieve,
and wherever one of the wires touches metal, the current snaps through for a
spark instead of jumping the points of the plug."
"Most amazing," the Colonel
growled. "It's strange I never had trouble like that with old Betsy."
"Probably your old car was
fitted with better wire in the first place," Gus suggested. "And
what's even more important, all these modern cars have high compression
motors compared with the old timers. The higher the compression, the
harder it is for the spark to jump at the spark plug points and sometimes,
as in this case, the rubber covering on the wire dries out and cracks and
the spark jumps through the cracks. It isn't anything to worry about.
.I'll put in some high-tension wire that will keep the juice where it
"There's something else
wrong here, Colonel," Gus continued. "It sounds to me as though the
timer is out of synchronism."
"What kind of a new-fangled
trouble is that?" Colonel Marrold asked.
"Just what you said a moment
ago," Gus replied. "It's like soldiers out of step. In nearly
all these eight-cylinder jobs, the timer is made so that one set of contact
points fires half the cylinders and another set fires the other half.
That's necessary, because, with a high-speed eight, it'd he mighty hard to
make one set of points work fast enough and still get sufficient current
through the coil for a fat spark. Point is, that if one set of contact
points is out of time with the other, half the cylinders will get a late
spark and they'll loaf on the job.
"You'll find that one set of
contact points is fixed so you can only adjust the amount of the break.
The other set is mounted on a plate so the whole business can be moved.
Each breaker arm produces the spark in four of the cylinders. After
you've set the fixed arm so it opens the right amount, the next job is to
move the plate holding the other one till it breaks the same."
"How do you tell when you
have it right?" Colonel Marrold asked."
"I was coming to that," said
Gus, "There are a lot of ways. The simplest I know of for the fellow
who does his own work is to open up the window that lets you see the timing
marks on the flywheel. Then you take a long piece of spark plug cable
and hook it on to the high-tension cable from the spark coil that ordinarily
sticks into the center hole of the distributor head. Bare a quarter of
an inch or so of the cable and hold the end close to the metal right beside
the opening to the flywheel.
"Have somebody turn the motor over
slow with the ignition turned on. With the spark jumping right beside
the inspection hole, it's a cinch to see whether the spark jumps as the
timing mark on the flywheel comes under the pointer. If it's off for
half the cylinders, move the breaker arm plate till you get it right."
"That sounds easy enough," Colonel
"It is easy," Gus maintained.
"An eight-cylinder motor is simpler in some ways than a six because it is,
after all, only two four-cylinder motors made into one. The ignition system
is one example. On some cars, even if one breaker arm went out of
commission, the motor would still run on four cylinders. Many of the
eights really use two carburetors - one for each set of four cylinders.
It looks like one carburetor because there's only one float bowl, but there
are two mixing chambers and two needle valves that have to be adjusted
"How is the best way to do that?"
asked Colonel Marrold.
Gus smiled. "Easiest way I
know of is to cut out half the cylinders while you adjust the low speed
setting for the others. You can do that either by disconnecting one of
the coil leads when there are two, or by wedging open one set of breaker
points with a bit of thick cardboard."