Engine Overhaul Flashcards
The main advantage of a drop forged crankshaft is that it:
a. Is the least expensive
b. Results in a strong crankshaft
c. Is easy to manufacture
d. Requires smaller counterweights
b. Results in a strong crankshaft
What effect reduces crankshaft vibrations?
a. Connecting rod bearing loads
b. Crankshaft bending moments
c. Flywheel loads
d. Torsional twisting of crankshaft
d. Torsional twisting of crankshaft
The part in the engine that tends to smooth out the flow of power by levelling off the power impulse is called:
a. Piston
b. Flywheel
c. Crankshaft
d. Balancer
b. Flywheel
Shot peening a crankshaft:
a. Relieves stress and gives a tough surface
b. Make the crankshaft weaker
c. Makes the surface smoother
d. Leaves small holes to hold oil
a. Relieves stress and gives a tough surface
It is important to check flywheel run out.
a. True
b. False
a. True
An engine balance shaft is used to:
a. Balance the crankshaft
b. Reduce torsional vibration
c. Smooth out power impulses
d. Smooth out engine vibration
d. Smooth out engine vibration
The crankshaft journals must be measure for the amount of [blank] and [blank].
a. Out of round and length
b. Diameter and width
c. Alignment and end play
d. Taper and out of round
d. Taper and out of round
A properly installed crankshaft with precision insert bearings but no rear seal installed:
a. Should turn with a heavy drag on it
b. Should not be able to be turned by hand
c. Should turn freely by hand
d. None of the above
c. Should turn freely by hand
When installing a wick type rear seal:
a. Trim the end flush with the parting surfaces.
b. Let the excess protrude.
c. Lay the excess across the parting surface.
d. Drive the excess down into the groove.
a. Trim the end flush with the parting surfaces.
A crankshaft rod bearing journal measures at standard diameter. There is 0.01222 wear only on the thrust side of the journal. In order to restore the units to serviceable condition, the rod journals will have to be ground:
a. 0.010”
b. 0.020”
c. 0.030”
d. 0.040”
b. 0.020”
Upper and lower bearing inserts automatically align when the cap is torqued.
a. True
b. False
b. False?
Counterweights on a crankshaft are used to:
a. Counter inertial loads caused by piston and rod velocity
b. Compensate for the weight of the piston and rod assemblies
c. Smooth out power impulse
d. Reduce torsional vibration
a. Counter inertial loads caused by piston and rod velocity
A four stroke 8 cylinder engine will have the crankpin positioned how many degrees apart?
a. 60 deg
b. 90 deg
c. 120 deg
d. 240 deg
b. 90 deg
If the crankshaft thrust bearing surfaces are worn beyond limits:
a. Replace the thrust bearings and install a thrust bearing shim kit.
b. Grind the thrust bearing surface and install undersize bearings.
c. Replace the crankshaft and bearings.
d. Leave it alone.
c. Replace the crankshaft and bearings.
Prior to removal, main bearing caps should be:
a. Carefully studied
b. Tapped lightly with a brass hammer
c. Thoroughly washed
d. Marked
d. Marked
Cylinders are measured near the top and near the bottom to determine:
a. Diameter
b. Out of round
c. Taper
d. Oversize
c. Taper
A typical repair for a cast iron block with 0.024” of cylinder taper would be:
a. Bore to 0.025” over and install new pistons.
b. Deglaze the cylinder and install new rings.
c. Hone, then rear to 0.030” over and install new pistons.
d. Bore, then hone to 0.030” over and install new pistons.
d. Bore, then hone to 0.030” over and install new pistons.
After machining, the cylinder walls are cleaned with:
a. Solvent
b. Soap and water
c. A hot tank
d. A glaze breaker
b. Soap and water
Crankshaft journals are inspected for:
a. Taper
b. Twist
c. Parallelism
d. All of the above
a. Taper
Which of the following is NOT a typical crankshaft journal wear pattern?
a. End to end taper
b. Hourglass taper
c. Fillet taper
d. Barrel taper
c. Fillet taper
If the block and rods are in good shape, main and rod bearing insert wear will be:
a. Even across the bearing face
b. Concentrated on apparently random areas of the bearing faces
c. In a short arc near the fillet
d. Greatest in the centre and minimal at the parting line
a. Greatest in the centre and minimal at the parting line?
Which of the following does NOT indicate a bent connecting rod?
a. Uneven side clearance on the piston skirt
b. Wear along the one edge of the bearing shells
c. Wear at opposite ends and side of the bearing shells
d. A diagonal pattern on the thrust face of the piston
a. Uneven side clearance on the piston skirt?
A connecting rod alignment fixture is used to check all of the following EXCEPT:
a. Offset
b. Stretch
c. Bend
d. Twist
b. Stretch
Press fit piston pins are installed with about:
a. 0.003” of interference
b. 0.002” of clearance
c. 0.001” of interference
d. 0.001” of clearance
c. 0.001” of interference
Standard procedure for repairing connecting rod big end bore stretch is to:
a. Bore to oversize
b. Hone to oversize
c. Machine back to standard size
d. Fit undersize bearings
c. Machine back to standard size?
Typical piston ring end gap for a 3.985” diameter piston would be:
a. 0.003 to 0.004”
b. 0.006 to 0.008”
c. 0.009 to 0.012”
d. 0.012 to 0.016”
d. 0.012 to 0.016”
When assembling the connecting rod onto a piston:
a. The rod can be installed in either direction.
b. The rod can be installed in one direction only.
c. The piston pin must be installed in the connecting rod first.
d. The piston notch is always to the rear of the engine.
b. The rod can be installed in one direction only.
A short block includes the:
a. Cylinder block
b. Crankshaft
c. Piston and rods
d. All of the above
d. All of the above
The purpose of the oil spit hole in the connecting rod is to:
a. Spit out excessive oil
b. Lubricated the main bearing
c. Lubricate the cylinder wall
d. Lubricate and cool the piston
c. Lubricate the cylinder wall
The purpose of the offsetting piston pin hold in the piston is to:
a. Improve piston clearance
b. Improve piston pin lubrication
c. Prevent piston slap
d. Reduce piston wear
d. Reduce piston wear
Press piston pins often fit snugly in the piston. The best way to remove or install a pin in the piston is to:
a. Heat the piston in an oven.
b. Warn the piston in hot water.
c. Use a rod heater.
d. Press the pin using proper press adaptors.
d. Press the pin using proper press adaptors.
A groove machined just below the crown of a piston is called the:
a. Relief groove
b. Heat dam
c. Heat expansion groove
d. Style line groove
b. Heat dam
Knurling a piston:
a. Reduces its diameter
b. Increases its diameter
c. Makes it stronger
d. Has no effect on it
b. Increases its diameter
A piston head usually measures less than the piston skirt by:
a. 0.003 to 0.004”
b. 0.010 to 0.020”
c. 0.300 to 0.400”
d. 0.020 to 0.040”
d. 0.020 to 0.040”
If the cylinder ridge is not removed before removing the piston / rod assemblies from the cylinder, then:
a. New piston rings will not fit properly.
b. It is possible to damage the piston land.
c. New piston rings will not break in properly.
d. Scoring of the cylinder wall will occur.
b. It is possible to damage the piston land.
Minimum piston ring end gap clearance should be [blank] per inch of piston diameter.
a. 0.010 maximum
b. 0.001 per inch of block length
c. 0.003 to 0.005
d. 0.0015 of an inch
c. 0.003 to 0.005
A dry sleeve is held in place by:
a. Knurling in the block
b. Interference press fit
c. Held by o-ring
d. Screw in block
b. Interference press fit
Coatings used on compression rings are plasma / ceramic
a. Babbitt and tin
b. Chrome and molybdenum
c. Steel and stainless steel
d. Oil and graphite
b. Chrome and molybdenum
In an operating engine, the hottest part of the piston is the:
a. Skirt
b. Ping grooves
c. Pin bosses
d. Head or crown
d. Head or crown
When installing crankshaft main bearings, the bearing to crankshaft clearance is to be checked with:
a. A micrometer
b. Plastigauge
c. A vernier calliper
d. A ruler and straight edge
b. Plastigauge
Tech A says that before removing the main bearing caps, each cap and the corresponding crankshaft web should be marked with a punch or number stamp.
Tech B says that marking main bearing caps is not necessary because the caps are interchangeable.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B
a. A only
Which of the following must be removed to thoroughly clean an engine block?
a. Core plugs
b. Oil gallery plugs
c. Both A and B
d. None of the above
c. Both A and B
Tech A says that piston rings should be removed with a special tool.
Tech B says that carbon deposits in the ring land should be left in place to assist the seating of new rings.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B
a. A only
The maximum cylinder taper normally allowed is:
a. 0.00015”
b. 0.006”
c. 0.015”
d. 0.060”
b. 0.006”
Which type of piston ring requires cleaning out holes or slots in the piston ring grooves so that oil can pass through it?
a. Oil ring
b. Compression ring
c. Chrome compression ring
d. Moly and chrome compression rings
a. Oil ring
A cylinder bore is checked for out of roundness with a:
a. Dial bore gauge
b. Telescoping gauge
c. Both A and B
d. Neither A nor B
c. Both A and B
Cylinder block flatness is checked by using:
a. A dial indicator
b. A vernier micrometer
c. A straight edge and feeler gauge
d. The old gasket and a micrometer
c. A straight edge and feeler gauge
Crankshaft journals must be checked for:
a. Taper and out of round
b. Stretch and squish
c. Crush and concentricity
d. Concentricity and roundness
a. Taper and out of round
It the crankshaft is reconditioned by grinding, and the new journal size is 0.020” less than the original size, you will have to use bearings that:
a. Fit tighter in the bearing bore.
b. Are 0.020 undersize.
c. Are standard size.
d. Will require different Plastigauge because bearing clearances are different.
b. Are 0.020” undersize
The main reason that bearings fail is because of:
a. Improper fitting
b. Dirt during assembly
c. Poor lubrication
d. Electrolysis
c. Poor lubrication
