5-23.
The interchangeability of piston-pin
bushing inserts is dependent on the
location of the
1.
oil holes
2.
piston pin
3.
needle bearing
4.
pin bushing
5-24.
Primarily,
why are piston pin bushings
reamed?
1.
To obtain larger oil holes
2.
To obtain correct lubricating flukes
3.
To obtain proper bore clearance
4.
To correct oil hole positioning
5-25.
Which of the following troubles can be
caused by misalignment of the connecting
rod?
1.
Binding of the piston
2.
Binding of the piston pin
3.
Binding of the connecting rod journal
4.
bearing
All of the above
5-26.
Which of the following tools should you
use to prevent overtightening of
connecting rod bolts?
1.
Socket wrench
2.
Torque wrench
3.
Strain gauge
4.
Thickness gauge
5-27.
Which of the following connecting rod
troubles is likely to occur because of
overstress?
1.
Cracked rods
2.
Misaligned rods
3.
Out-of-round bearing bores
4.
Plugged oil passages in the rods
Question 5-28 is to be judged True
or False.
5-28.
You should repair by welding or brazing
any cracked connecting rods discovered
during engine overhaul.
Learning Objective: Point out some
of the causes of engine shaft and
bearing failure and indicate methods
of reducing the most commonly
encountered troubles
5-29.
5-30.
5-31.
5-32.
5-33.
5-34.
5-35.
What is the usual cause of fatigue
failure of the crankshaft journal
bearings?
1.
Loose bearing shells
2.
Improper lubrication
3.
Cyclic peak loads
4.
Each of the above
What effect will extreme overspeeding of
an internal combustion engine have on the
main journal bearings?
1.
Failure of the upper halves only
2.
Failure of the lower halves only
3.
Either 1 or 2 above
4.
Failure of both the lower and the
upper halves
Which of the following factors could be
the cause of crankshaft fatigue failure?
1.
2.
3.
4.
Improper functioning of the vibration
damper
Improper quenching or balancing by
the manufacturer of the crankshaft
Flexing of the crankshaft under load
All of the above
The crankshaft of a reciprocating engine
may be responsible for which of the
following conditions?
1.
Lineal impulses
2.
Natural vibrations
3.
Torsional impulses
4.
Natural frequencies
Questions 5-33 and 5-34 are to be judged
True or False.
The term "critical speeds" applies to all
moving members of machinery with the
exception of reciprocating-type engines.
Continuous engine operation within the
critical speed range may result in
breakage of the crankshaft and connecting
rod bearing difficulties.
Assume a propulsion diesel engine has a
tachometer with the area between 700 rpm
and 750 rpm conspicuously marked in red.
The speeds within this range are the
1.
maneuvering engine speeds
2.
critical engine speeds
3.
most efficient operating speeds
4.
smoothest operating speeds
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