Diesel Engine Fundamentals test #1
When checking a cylinder block deck for warpage with a thickness gauge and straight edge, what would be a typical maximum specification?
0.004 inches
When a valve interference angle is used, which of the following would be a typical specification?
0.5-1.0 degree more than the seat
What is the rocker ratio of a rocker that converts 1 inch of cam lift into 1.5 inches of travel?
1.5:1
When testing valve spring tension, within what percentage of the original tension specification should the measurement be?
10%
In an in-line 6 cylinder, 4-stroke cycle diesel engine, what is the spacing between power strokes?
120 degrees
To what depth should a liner crosshatch be machined to?
15-20 micro inch
How many keepers are required to retain one cylinder valve?
2
What percentage of cylinder combustion heat is typically absorbed by the piston assembly?
20%
When a hone is used to glaze-bust a liner what is the recommended grit stone rating?
200-250
To what temperature should a camshaft gear usually be heated prior to installation on a camshaft?
300 Degrees
What would be the highest thermal efficiency achievable in a current truck diesel engine?
40%
Which of the following would provide higher valve seating force?
45 degree cut valve
What is the recommended crosshatch crossover angle on a typical liner?
45 degrees
What is a typical compression pressure achieved in a current highway truck diesel engine?
600 psi
If a diesel engine has a thermal efficiency of 35%, what percentage of the heat energy of the fuel is discharged as rejected heat?
65%
The four strokes of the diesel cycle take place over what?
720 degrees
What is used to retain friction bearings?
Alignment tabs and crush bearings
What does the acronym ASE represent?
Automotive Society of Engineers
Which of the following acronyms is used by manufacturers to indicate actual fuel consumption?
BSFC
Which of the following components would be classified as part of the engine housing?
Blocks, liners, pistons, manifolds, heads
Technician A says that Monotherm pistons feature a bushing-less wrist pin bore. Technician B says that forged steel pistons are usually equal in weight to equivalent bore aluminum trunk pistons because much less material is used in their construction. Who is correct?
Both Techs
Technician A says that cylinder block torque twist can be the result of high cylinder pressures. Technician B says that cylinder block torque twist can be the result of drivetrain forces outside of the engine. Who is correct?
Both Techs
Technician A says that diesel fuel is composed of roughly 85% carbon. Technician B says that diesel fuels commonly contain around 15% hydrogen. Who is correct?
Both Techs
What material is used in the manufacturing of most commercial diesel engine cylinder blocks today?
Cast Iron
Who entered the first diesel powered automobile in the Indy 500?
Clessie Cummins
Who is known as the father of the truck diesel engine?
Clessie Cummins
Valve setting specifications are provided by the OEM for performing overhead adjustment when engine temperature is what?
Cold
Which type of ring joint is most effective in sealing cylinder blow-by gas?
Compression rings
What term is used to describe a gear that permits zero lash between intermeshing gears and also eliminates the risk of gears radially loading each other when at operating temperature?
Concept gear
Where does a wrist pin fit to a piston?
Connecting rod eye or skirt
What does the Japanese word kaizan translate as?
Continous Improvement
What is another way of describing the toroidal recess in a Mexican hat type piston?
Crater
Which federal agency is responsible for setting federal noxious emissions standards?
EPA
Which of the following would be the most likely cause of a connecting rod tensile failure?
Engine is oversped
What is another name for the power stroke in the engine cycle?
Expansion Stroke
What is the recommended tool used to check valve lash dimension?
Feeler gauge
What is the reason that OEMs specify greater valve lash for exhaust valves?
For the extra heat on the exhaust side
Which of the following piston types is the most common in large bore highway diesel engines built after 2007?
Forged Steel trunk
Who invented the aeolipile or reaction turbine?
Hero
When is valve float more likely to occur?
High engine speeds
What is the most common method of surface hardening the journals on a heavy-duty crankshaft?
Induction Hardening
When a cylinder valve is manufactured with a stem and head of different alloys, what is commonly used to join each part?
Inertial Welding
When a valve cam ramps from base circle to outer base circle, what is happening to the valve it actuates?
It opens the valve
When a camshaft has three profiles per engine cylinder, what is the center cam profile used for?
Jake Brake
Who invented the centrifugal governor and the crank/throw principle?
James Watt
Which of the following would be the appropriate way to describe a 15 liter truck diesel engine?
Large Bore Diesel engine
Which of the following tools should be used to check to operation of an installed valve rotator?
Marking the stem and guide with a marker pen and then tapping the valve with a nylon hammer to see if it rotates
What does the left side camshaft actuate in a pre-2010 Cummins ISX engine?
Mechanical Injectors
Which of the following engines uses a parent bore cylinder block?
Mercedes Benz Small bore engines
When variable valve timing (VVT) is used on a Caterpillar diesel engine, which of the following becomes variable?
Moment of intake valve closure
What is the primary advantage of a cracked connecting rod?
More ridges so a greater clamping force
What term is used to describe the tendency of an object in motion, to want to stay in motion?
Newton's first law
When main bearing shells are installed to an engine cylinder block, what should be used to lubricate the backing plate?
Nothing
When does an oil control ring apply lubricant to the cylinder wall?
On the upstroke, scrape it on the downstroke
Which of the following would provide the correct cam lift dimension?
Outer Base Circle minus Inner Base Circle
Which of the following terms is used to describe the largest radial dimension of a cam profile?
Outer base circle
Which of the following correctly identifies torque rise rpm?
Peak torque to rated speed RPM
Which of the following components is an engine powertrain component?
Pistons, rings, crankshaft, connecting rods
What recently introduced technology enables the use of aluminum cylinder blocks in light and medium duty diesel engines?
Plasma Transfer Wire Arc (PTWA)
A crankshaft has been damaged by a spun bearing. What would be the recommended OEM repair?
Replace the crankshaft
Viewed from the front, a Cummins ISX rotates clockwise. On which side are the piston major thrust faces located?
Right Side
What is the ring land and groove area of a piston known as?
Ring Belt
Which of the following features would be required in an aluminum alloy, trunk type piston when used in a commercial diesel application?
Ring groove insert (Ni-Resist)
Which of the following best describes the mechanical role of a crankshaft throw in relation to the crankshaft centerline?
Shows how far the piston moves up and down in the cylinder
Which of the following terms correctly describes a Mahle Monocomp piston?
Single piece steel trunk piston
How would a commercial truck diesel engine with a displacement of 6.8 liters be classified?
Small Bore diesel engine
Which of the following is another way of describing valve keepers?
Split Locks
What is mainly responsible for a piston ring's ability to seal cylinder pressure?
Stagger,
Where is a piston ring installed in the piston assembly?
Staggered in the top of the piston called the land
Which code is associated with the ASE Diesel Engines certification test?
T2 test
Technician A says that ASE tests can now be taken online at any time of year. Technician B says that when taking ASE tests on a computer, the tests are not timed. Who is correct?
Tech A
Technician A says that current forged steel trunk pistons use a shorter wrist pin than comparable articulating piston assemblies. Technician B says that a disadvantage of forged steel trunk pistons such as Monotherm is much greater weight than comparable bore aluminum trunk pistons. Who is correct?
Tech A
Technician A says that the upside of a piston ring is often identified by a dot. Technician B measures a ring end gap of 0.018 inch in 5-inch diameter cylinder bore and says that it almost certainly exceeds the OEM specification. Who is correct?
Tech A
Technician A says that a disadvantage of forged steel trunk pistons is reduced headland volume when compared with articulating pistons. Technician B says that when a diesel engine uses lighter pistons, higher RPMs are possible. Who is correct?
Tech B
Technician A says that camshaft rotation must be in the same direction as crankshaft rotation. Technician B says that camshaft rotation may be opposite crankshaft rotation. Who is correct?
Tech B
Technician A says that camshafts are used to convert linear motion into rotary force. Technician B says that a valve rocker can be considered to be part of the valve train actuated by cam profile. Who is correct?
Tech B
Technician A says that engines using quiescent combustion dynamics tend to use more aggressive Mexican hat cones. Technician B says that injected fuel droplets are directed into the crater (toroidal recess) in Mexican hat piston crowns. Who is correct?
Tech B
When variable valve timing (VVT) is used, what controls the VVT actuator?
The ECM
When fuel is injected into a diesel engine cylinder, to which part of the piston are the atomized droplets targeted?
The crown of the piston
Which of the following is another way of saying kinetic energy?
The energy of motion
What is the reason most manufacturers suggest that a valve bridge be removed from the engine before backing off the adjusting screw?
The guide is vulnerable to bending
Who was responsible for building the first steam engine capable of performing any real work?
Thomas Savery
If crankshaft endplay is higher than specified, which of the following should be used to correct the condition?
Thrust Bearing
Which of the following best describes the sectional shape of a keystone ring?
Trapezoid
What is another way of saying manifold boost?
Turbo Boost
Which of the following is the more accurate way of expressing torque?
Turning Effort
What should be used to check an out-of-engine camshaft for bend?
V-Blocks and dial indicator
Who invented the inlet metering, rotary distributor pump?
Vernon Roosa
Which of the following correctly defines piston swept volume?
Volume of the cylinder from top dead center to bottom dead center
What is used to link a piston with a connecting rod?
Wrist Pin
Which of the following terms means the same thing as a piston pin?
Wrist Pin
If an engine is run for maximum mechanical efficiency, where should peak cylinder combustion pressure be achieved?
around 15 degrees after top dead center
Which of the following is generally a disadvantage of an articulating piston assembly when compared to an aluminum trunk piston?
d. Weight
When main bearing shells are installed to an engine cylinder block, what should be used to lubricate the bearing face?
nothing
What did James Watt achieve when he manufactured his 1765 steam engine?
quadruple the thermal efficiency of any previous engine
If a single slab cylinder head is used on an in-line 6-cylinder diesel engine, how many engine cylinders will the cylinder head cover?
six
What was the world's first automobile powered by?
steam
In a heavy-duty diesel engine, which of the following is more likely to be described as tuned?
the exhaust manifold
When following a cylinder head bolt torque sequence while torquing a single slab cylinder head, which bolts should be torqued last in the sequence?
the outside bolts
What is known as headland volume in a piston assembly?
volume between crown and top compression ring
