When Bert Hibbard first brought his 1949 sedan
into the Model Garage, Gus Wilson figured that this would be one of the
simplest jobs he had ever tackled. The way things turned out, Gus had a
mystery on his hands, and half the people in town were talking about it and
looking back over their shoulders.
Some folks were quick to
declare that Hibbard's distributor cap had been exploded by atomic
The car came in running
rough and occasionally backfiring. Gus saw what was wrong as soon as he
lifted the hood. The distributor cap was hanging loosely in the air, on the
ends of the spark plug wires and the center, high-tension wire from the
The two flat, spring-wire
clips, which were supposed to hold the cap on firmly, were unsnapped. The
cap was held in place by the stiff wires just enough so that the motor was
able to run raggedly.
Gus lifted the cap and
inspected the inside with a light. Bouncing around loosely, it had taken a
beating from the revolving rotor.
Off with the Old Cap-On
with the New
"Sorry, Bert," he told
Hibbard. "This is going to cost you a new distributor cap. This one's had
it. I wonder how those spring clips came loose. Has anyone been working
"No," Hibbard declared,
scowling. "And what's more, it was running perfectly when I put it in the
garage last night. I'm ready to bet that Mike Regan sneaked in during the
night and worked that distributor cap loose. You know, Gus, he's the
character who threw nails on my lawn and deliberately ruined my power mower
a couple of years back."
Gus knew all about the
power mower. Mike Regan, a large and ordinarily well-liked and friendly
man, lived next door to Hibbard. While building a new garage, he had
dropped some nails on Hibbard's lawn. Mike claimed this was accidental.
Hibbard claimed otherwise.
The two had been in each other's hair ever since.
"Pshaw!" Gus exclaimed.
"Now I don't think Mike would do a thing like that, even as a joke."
Gus Ponders a Mystery
Gus installed a new
distributor cap and, while he was doing so, pondered on how those two spring
clips could have come free during a night in Hibbard's garage. If the car
had been all right when Bert put it away, and was running this way when it
started in the morning, someone must have tinkered with it. Still, the two
spring clips could have jumped loose of themselves. To make sure that they
didn't do it again, Gus bent them slightly so that they snapped strongly
into the niches of the cap. The car now started easily, ran smoothly.
But a week later Hibbard
called the garage again and this time he really was put out.
"Gus," he yelled into the
phone, "can you come right over?
Regan's been up to his
tricks again This time he smashed my distributor cap. You should see it -
smashed to smithereens. I've a mind to have Regan arrested."
When Gus got to Hibbard's
home, he found Bert and Mike Regan standing outside the garage, engaged in
"I tell you, Regan," Bert
was saying as Gus came up. "I'm giving you just one more chance. I'm
putting a padlock on my garage nights from now on, and so help me - "
"Why blame me," Regan
yelled, "when things are blowing up all over the country? It's those atomic
bombs they're setting off.
Why, out West the windows
are all pock-marked, and some of them just exploding. Why I heard of a man
who saw pink snow right after that last bomb they set off."
"Morning, boys," Gus said
genially, stepping out of his service car with his tool kit. "What's this I
hear about that new distributor cap exploding? Sounds like a joke." "Take a
look for yourself, Gus," Hibbard said grimly.
Lifting the hood, Gus was
astonished to see that the new distributor cap had literally been smashed to
bits. The wire sockets hung in the air, still attached to the wires, but
the rest of the cap was scattered about in pieces. This did indeed, look
like vandalism. Perhaps, Gus thought, the distributor-shaft bearing is badly
worn, wobbling the rotor around so that it broke the cap.
This hardly seemed
possible, but Gus made an inspection for side play. There was none.
Gus straightened up, took
his pipe out of his pocket. While he slowly packed and lit it his mind was
busy. Could Mike Regan have done this, as Hibbard claimed? Or possibly
Hibbard had aroused the antagonism of some mechanically minded youngster in
town. Gus turned to meet Mike Regan's blue eyes squarely. Then he turned to
"I brought a new
distributor cap." He said shortly. "Maybe you'd better padlock your garage
after this, Bert." The second new cap installed, Gus drove back to the
Model Garage. Several times during the next few days he saw Bert Hibbard
driving the car around town. Apparently it was running well and the padlock
on the garage had finally ended the matter.
But Mike Regan hadn't been
willing to let it drop there. He felt that he was under suspicion. He took
great pains to explain to folks that he had been innocent. He declared that
almost anybody's distributor cap might explode, even as car windows were
being mysteriously pock-marked.
"Atomic radiation, my eye!"
Stan Hicks, Gus' helper, exclaimed. “Somebody must have it in for Bert. It
could be Mike Regan.”
Exploding Cap Sets Off Town Talk
But Mike's talk went from
mouth to mouth. Rumors flew. Folks dropped in at the Model Garage to
question Gus about the mysteriously exploded distributor cap.
This was the situation when
another distributor cap literally blew up on Bert Hibbard's car while it
was sitting in his garage. This time the garage had been securely locked.
When Gus got the news he tossed his kit into the service car with a grim
expression on his normally genial features.
"This settles it," he told
Stan Hicks. "If that garage was locked, as Hibbard says it was, no one has
been doing this. It's simply a mechanical problem. That I can handle."
This time Gus found Hibbard
and Regan circling each other, perplexed, talking softly and warily.
"The garage ," Regan
reminded Hibbard, "was locked all night, until you opened it this morning to
get out your car. Maybe you think I know how to pick locks, Bert?"
"Maybe," Hibbard said.
"It's those atomic-bomb
explosions," Regan declared.
"Maybe," Gus cut in, "one
of those flying saucers landed and one of those little green men from Mars
No Flying Saucers for
Gus was all business now,
his eyes alert beneath his heavy, graying brows. The distributor cap again
was scattered about in bits. What was he to do now? Gus asked himself. One
thing he wouldn't do was to blame the neighbors, atomic explosions or flying
saucers. Perhaps that new rotor he had put in was too long - yet he knew it
Inspecting the broken
pieces of distributor cap, Gus gathered the impression that they had been
blown outward rather than smashed inward by an outside blow.
In a gasoline engine, this
meant gas fumes, ignited by a spark, in a confined area. In the distributor
there was a confined area, and as these explosions must have occurred just
at the moment Hibbard tried to start his car, there would be a spark from
the flash of the ignition points. The sound of the explosions might have
been muffled by the grinding of the starter motor.
But how could gas get in
the distributor? Could it get from the crankcase, up through the
distributor shaft? It was possible but not probable, in enough concentration
to fire. Where else could gas fumes come from? What other opening was
there into the distributor from a source of gas or gas fumes? How about the
automatic vacuum spark control? Gus eased his back muscles as he thought
"Stuck, Gus?" Hibbard
"Maybe," Gus said
The vacuum control, a
diaphragm connected by tubing to the intake manifold, retarded the
distributor timing under heavy load, and advanced it when the load eased up.
Thus the manifold was a possible source of gas fumes. What if the
diaphragm were punctured?
If conditions were right
and fumes collected in the distributor, a spark from the points would blow
the cap apart. But if conditions were not just right, if the fumes did not
collect in the right proportions, it wouldn't happen. Gus snapped his
fingers. This would account for several days elapsing between explosions.
He began to tear down the vacuum spark-advance control unit.
Sure enough, the diaphragm
Bending Clips Caused
"It didn't blow the cap
apart the first time," Gus explained to Hibbard, "because the spring clips
flew off easily. But after I bent them and attached them firmly the cap
exploded under pressure."
Gus's installation of a new
vacuum control unit ended the mystery of the exploding distributor caps,
even to the satisfaction of those who were inclined to see fiery saucers,
pink snow and little green men. And the next Saturday morning, driving by
Hibbard's place, Gus saw Bert holding the ladder for Mike Regan while he
sawed at a dead limb on the big maple that hung over their adjoining lawns.