Technician and Service
Technician A says that camshaft rotation must be in the same direction as crankshaft rotation. Technician B says that camshaft rotation may be opposite to Crankshaft rotation. who is right?
Technician B
What should be used to check an out of engine camshaft for bend?
inside micrometer, outside micrometer, dial bore gauge, dial indicator and v- blocks
dial indicator and v-blocks
Which type of engine timing gear tooth design has the advantage of low thrust loads?
spur, helical, amboid, hypoid
Spurs
To what temperature should a camshaft gear usually be heated prior to installation on a camshaft?
100, 200, 300, 400
300 degrees Fahrenheit
What part of a rocker contacts either the valve stem or valve bridge?
Adjusting screw, boss, pallet, yoke
Pallet
Technician A says that pre-2010 cummins isx uses dual ohc design. Technician B says that a post 2010 cummins isx uses single ohc design. Who is correct?
Both
Which of the following tools should be used to check the operation of an installed valve rotator?
light nylon hammer, dial bore gauge, outside micrometer, stethoscope
light nylon hammer
a four stroke cycle diesel engine has a crankshaft gear with 45 teeth. how many teeth should the camshaft gear have if it is direct driven?
22, 45, 90, 180
90
Which of the following terms is used to describe the shortest radial dimension of a cam profile?
inner base circle, outer base circle, lift flank, unload flank
inner base circle
What is the reason that OEMS specify greater valve lash for exhaust valves?
they run hotter and expand more, they run cooler and contract less, they are shorter than intake valves, they are longer than intake valves
They run hotter and expand more
which of the following is NOT a diesel engine feedback assembly?
timing gear train, camshaft, valve train, connecting rod
Connecting Rod
Which of the following could be used to measure cam bushing bore in a cylinder block?
deck micrometer, outside micrometer, dial bore gauge, plastigage
Dial bore gauge
which of the following specifications for engine timing gear train backlash would be typical?
100mm, 200mm, 400mm, 800mm,
200mm
Which of the following terms is used to describe the largest radial dimension of a cam profile?
inner base circle, outer base circle, lift flank, unload flank
outer base circle
When machining valves, which of the following specifications requires close observation?
fillet, valve protrusion, valve recession, margin
Margin
Which of the following is a required test for a push tube before returning to service?
measure diameter with micrometer, measure length with shop ruler, roll on a true flat surface, magnetic flux test
roll on a true flat surface
Which of the following operates at the highest temperatures?
exhaust valves, intake valves, solid lifters, rockers
Exhaust valves
If a cam profile is described as being mostly outer base circle, what would be true of the train it actuates?
actuated twice per revolution, actuated every other revolution, loaded for most of the cycle, unloaded for most of the cycle
Loaded for most of the cycle
The injector cam profile on a camshaft shows visible deterioration of the hard surfacing. what should be done?
polish with emery cloth, machine smooth, replace camshaft, repair by metalizing
Replace camshaft
When testing valve spring tension, within what percentage of the original tension specifications should the measurement be?
5 percent, 10 percent, 15 percent, 20 percent
10 percent
Which of the following is NOT found in medium and heavy duty truck diesel engines?
cast iron solid lifters, middle alloy steel solid lifters, roller type cam followers, hydraulic lifters
Hydraulic lifters
What is a major advantage of a valve rotator?
sharper interference angle may be used, reduce carbon build up on seat, lower tension valve springs may be used, exhaust valves run cooler
reduce carbon build up on seat
When valve cam ramps from base circle to outer base circle what is happening to the valve it actuates?
it is stationary, it is opening, it is closing, it is fully open
it is opening
Which of the following would provide the correct cam lift dimension?
obc minus ibc, ibc minus obc, shaft centerline to toe dimension, lift flank minus unload flank dimension
OBC minus IBC
When is valve float more likely to occur?
Engine lugdown, engine rated speeds, low engine speeds, high engine speeds
High engine speeds