ASE A1 Test Prep – Engine Repair
Technician A says that a defective harmonic balancer can cause inaccurate ignition
timing readings. Technician B says that a defective harmonic balancer can cause a
broken crankshaft. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Both technicians are right. The outer ring on a defective harmonic balancer can slip,
causing inaccurate ignition timing readings. A broken crankshaft can also result from an
incorrect or defective balancer.
Technician A says the flywheel on an externally balanced engine can only be installed
in one position on the crankshaft flange. Technician B says that flywheel runout should
be checked with a straightedge and feeler gauge. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
On externally balanced engines, the flywheel must be correctly indexed when it is
mounted on the crankshaft to maintain engine balance (many flywheels have bolt holes
that are unevenly spaced so they can only go on one way). Make certain that index
marks are properly aligned when installing the flywheel. Runout on the face of the
flywheel is checked with a dial indicator.
All of the following could cause an engine to overheat EXCEPT:
A. Defective fan clutch
B. Clogged cooling system
C. Broken fan shroud
D. Stuck open thermostat
A thermostat that is stuck open will not restrict coolant flow. A clogged cooling system
would restrict coolant flow and cause engine overheating. A defective fan clutch and
broken fan shroud would both reduce air flow through the radiator and could cause
engine overheating.
All of the following can cause an engine oil leak EXCEPT:
A. Cracked valve cover gasket
B. Stuck open PCV valve
C. Worn rear main seal
D. Worn piston rings
,A cracked valve cover gasket and worn rear main seal would allow oil to leak past their
damaged surfaces. Worn piston rings would cause excessive crankcase pressure and
push oil past seals and gaskets that are in good condition. A stuck open PCV would not
cause excessive crankcase pressure, but would cause a vacuum leak and cause the
engine to run rough at idle.
Technician A says that the engine should be accelerated when checking vacuum
advance. Technician B says that the engine should be accelerated when checking
centrifugal advance. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
The weights and springs in a centrifugal advance mechanism are calibrated to advance
ignition timing as engine speed increases, therefore the engine must be accelerated
when checking centrifugal advance. Vacuum advance works only in response to
changes in vacuum applied to the unit, therefore changes in ignition timing can be seen
with a timing light while applying vacuum with the engine at idle.
Technician A says that if the ring ridge at the top of the cylinder is not removed, damage
to the new piston and rings can result. Technician B says when the block will be bored
for oversize pistons, removing the ridge is not necessary. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Both technicians are right A new ring can contact the old rounded ring ridge. This will
push the bottom part of the ring groove down, possibly affecting second ring clearance.
If the block is to be bored, removal of the ring ridge will not be necessary.
All of the following could cause reduced performance from a turbocharged engine
EXCEPT:
A. Dirty air filter
B. Restricted exhaust system
C. Worn turbocharger bearings
D. Stuck closed wastegate
A dirty air filter and restricted exhaust would inhibit air flow through the turbocharger and
reduce performance. Worn turbocharger shaft bearings could cause the rotating
assembly to bring or drag and reduce performance. A stuck open wastegate would
reduce performance. However, a stuck closed wastegate would cause overboost.
All of the following statements about batteries are true EXCEPT:
A. A fully charged battery should have a specific gravity of 1.260.
, B. If the open circuit voltage is less than 12.4 volts, charge the battery at a slow rate.
C. A battery is load tested to one-third its CCA (cold cranking amps) rating for 15
seconds.
D. At the end of the load test, battery voltage must be 9.6 volts or more.
During a load test, a battery should be loaded to one-half its CCA rating for 15 seconds.
Technician A says that a a deep gouge in the cylinder bore can be repaired by installing
a sleeve. Technician B says a crack in a cylinder bore requires that the block be
replaced. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
A sleeve can be used to repair a damaged or cracked cylinder bore.
When a cylinder head with an overhead camshaft is discovered to be warped, which of
the following is the MOST correct repair option?
A. Replace the head
B. Check for cracks, straighten the head, resurface the head
C. Resurface the head, then straighten it
D. Straighten the head, resurface the head, then check for cracks
It makes no sense to perform repairs on a cylinder head that might not be usable. The
head should first be checked for warpage and cracks. If the top of the head is warped
enough to interfere with cam bore alignment and/or restrict free movement of the
camshaft, the head must be straightened before it is resurfaced.
Technician A says that crankshaft connecting rod journals typically experience the most
wear at BDC (bottom dead center). Technician B says that bearing journal diameter
should be measured at the center and at both ends. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Connecting rod journals typically experience the most wear at TDC (top dead center).
Because bearing journals can experience taper wear, barrel wear or hourglass wear,
they should be measured at the center and at both ends.
All of the following can result from resurfacing a cylinder block EXCEPT:
A. Change in the camshaft timing on an overhead camshaft engine
B. Change in the alignment between the cylinder
C. Decreased compression
D. Change in the valve train geometry on a pushrod engine.
Technician A says that a defective harmonic balancer can cause inaccurate ignition
timing readings. Technician B says that a defective harmonic balancer can cause a
broken crankshaft. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Both technicians are right. The outer ring on a defective harmonic balancer can slip,
causing inaccurate ignition timing readings. A broken crankshaft can also result from an
incorrect or defective balancer.
Technician A says the flywheel on an externally balanced engine can only be installed
in one position on the crankshaft flange. Technician B says that flywheel runout should
be checked with a straightedge and feeler gauge. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
On externally balanced engines, the flywheel must be correctly indexed when it is
mounted on the crankshaft to maintain engine balance (many flywheels have bolt holes
that are unevenly spaced so they can only go on one way). Make certain that index
marks are properly aligned when installing the flywheel. Runout on the face of the
flywheel is checked with a dial indicator.
All of the following could cause an engine to overheat EXCEPT:
A. Defective fan clutch
B. Clogged cooling system
C. Broken fan shroud
D. Stuck open thermostat
A thermostat that is stuck open will not restrict coolant flow. A clogged cooling system
would restrict coolant flow and cause engine overheating. A defective fan clutch and
broken fan shroud would both reduce air flow through the radiator and could cause
engine overheating.
All of the following can cause an engine oil leak EXCEPT:
A. Cracked valve cover gasket
B. Stuck open PCV valve
C. Worn rear main seal
D. Worn piston rings
,A cracked valve cover gasket and worn rear main seal would allow oil to leak past their
damaged surfaces. Worn piston rings would cause excessive crankcase pressure and
push oil past seals and gaskets that are in good condition. A stuck open PCV would not
cause excessive crankcase pressure, but would cause a vacuum leak and cause the
engine to run rough at idle.
Technician A says that the engine should be accelerated when checking vacuum
advance. Technician B says that the engine should be accelerated when checking
centrifugal advance. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
The weights and springs in a centrifugal advance mechanism are calibrated to advance
ignition timing as engine speed increases, therefore the engine must be accelerated
when checking centrifugal advance. Vacuum advance works only in response to
changes in vacuum applied to the unit, therefore changes in ignition timing can be seen
with a timing light while applying vacuum with the engine at idle.
Technician A says that if the ring ridge at the top of the cylinder is not removed, damage
to the new piston and rings can result. Technician B says when the block will be bored
for oversize pistons, removing the ridge is not necessary. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Both technicians are right A new ring can contact the old rounded ring ridge. This will
push the bottom part of the ring groove down, possibly affecting second ring clearance.
If the block is to be bored, removal of the ring ridge will not be necessary.
All of the following could cause reduced performance from a turbocharged engine
EXCEPT:
A. Dirty air filter
B. Restricted exhaust system
C. Worn turbocharger bearings
D. Stuck closed wastegate
A dirty air filter and restricted exhaust would inhibit air flow through the turbocharger and
reduce performance. Worn turbocharger shaft bearings could cause the rotating
assembly to bring or drag and reduce performance. A stuck open wastegate would
reduce performance. However, a stuck closed wastegate would cause overboost.
All of the following statements about batteries are true EXCEPT:
A. A fully charged battery should have a specific gravity of 1.260.
, B. If the open circuit voltage is less than 12.4 volts, charge the battery at a slow rate.
C. A battery is load tested to one-third its CCA (cold cranking amps) rating for 15
seconds.
D. At the end of the load test, battery voltage must be 9.6 volts or more.
During a load test, a battery should be loaded to one-half its CCA rating for 15 seconds.
Technician A says that a a deep gouge in the cylinder bore can be repaired by installing
a sleeve. Technician B says a crack in a cylinder bore requires that the block be
replaced. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
A sleeve can be used to repair a damaged or cracked cylinder bore.
When a cylinder head with an overhead camshaft is discovered to be warped, which of
the following is the MOST correct repair option?
A. Replace the head
B. Check for cracks, straighten the head, resurface the head
C. Resurface the head, then straighten it
D. Straighten the head, resurface the head, then check for cracks
It makes no sense to perform repairs on a cylinder head that might not be usable. The
head should first be checked for warpage and cracks. If the top of the head is warped
enough to interfere with cam bore alignment and/or restrict free movement of the
camshaft, the head must be straightened before it is resurfaced.
Technician A says that crankshaft connecting rod journals typically experience the most
wear at BDC (bottom dead center). Technician B says that bearing journal diameter
should be measured at the center and at both ends. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Connecting rod journals typically experience the most wear at TDC (top dead center).
Because bearing journals can experience taper wear, barrel wear or hourglass wear,
they should be measured at the center and at both ends.
All of the following can result from resurfacing a cylinder block EXCEPT:
A. Change in the camshaft timing on an overhead camshaft engine
B. Change in the alignment between the cylinder
C. Decreased compression
D. Change in the valve train geometry on a pushrod engine.
