FINAL TEST!!!
Technician A says that preignition is harmless. Technician Bsays that detonation can cause severe engine damage. Who is correct?
b. B only
Technician A says that the intake valve is often smaller than the exhaust valve. Technician B says that the exhaust valves can operate more efficiently because the air is under pressure when the exhaust valve opens. Who is correct?
b. B only
A valve seat is too wide. The area of contact is high toward the head of the valve. The seat should be cut with a ________ stone.
d. 30-degree
Fuel is generally available in octane ratings of all of the following EXCEPT:
d. 99 octane
A low steady vacuum gauge reading with the gauge connected to the intake manifold may be caused by:
d. A vacuum leak
A variable-length intake manifold is designed to increase:
d. Airflow at high rpm
A reason to install a remanufactured engine may be:
d. All of the above
An engine bedplate:
d. All of the above
Piston head designs can:
d. All of the above
Some of the vital information on the repair order are:
d. All of the above
Specialized engine rebuilding shops usually work on
d. All of the above
The service writer needs to:
d. All of the above
Undersize bearings:
d. Are used when the crankshaft has been ground
Spark ignition occurs:
d. BTDC on the compression stroke
Each of the following is a typical type of valve timing mechanism EXCEPT:
d. Band
During the compression stroke in a four-cycle engine:
d. Both valves are closed.
The test-drive:
d. Can be useful when diagnosing engine problems
Engine bearings may be made with each of the following as a liner EXCEPT:
d. Cast iron
When a spark ignites the air and fuel mixture, ____ occurs.
d. Combustion
Valve stem seals:
d. Control oil flow to the valve stem
Camshaft ____ is how long the valve stays open.
d. Duration
An engine has low-running compression on two out of four cylinders; the cranking compression was normal.Technician A says the camshaft lobes may be worn.Technician B says the head gasket may be blown.Who is correct?
a. A only
Technician A says that a worn camshaft lobe can cause reduced engine power. Technician B says that a bent camshaft should be straightened. Who is correct?
a. A only
Technician A says that a CNC machine can mill an engine part with more accuracy than a regular machine. Technician B says that using a CNC will usually result in more customer comebacks. Who is correct?
a. A only
Preparing the engine for removal is being discussed. Technician A says you should read through the service procedure for the specific vehicle before beginning. Technician B says that the air-conditioning refrigerant should be vented to the atmosphere. Who is correct?
a. A only
A customer says his vehicle overheats only in traffic while idling.Technician A says the fan may be inoperative. Technician B says the thermostat may be stuck closed. Who is correct?
a. A only
Technician A says that an engine rebuilding technician at a machine shop must be able to make precision measurements.Technician B says that not much math is involved when you are working as an engine rebuilding technician at a machine shop. Who is correct?
a. A only
Technician A says that being off on valve timing as little as three teeth can result in valve-to-piston contact.Technician B says that advancing the camshaft one tooth will improve high rpm breathing.Who is correct?
a. A only
Technician A says that electric cooling fans reduce the load on the engine, saving horsepower. Technician B says that a clutch-type fan slips on the pump hub when the engine is hot. Who is correct?
a. A only
Technician A says that if you replace the camshaft, you should replace the lifters. Technician B says that lifters should be slightly concave on their face. Who is correct?
a. A only
Technician A says that lifters are typically replaced during an engine overhaul.Technician B says that too little valve clearance can cause valvetrain clatter.Who is correct?
a. A only
Technician A says that overlap improves volumetric efficiency at higher rpm. Technician B says that overlap reduces HC emissions. Who is correct?
a. A only
Technician A says that removing material from the valve stem contact area of the rocker arm may affect rocker arm geometry. Technician B says that intake manifold replacement will change rocker arm geometry. Who is correct?
a. A only
Technician A says that the sealing surfaces must be perfectly clean before fitting a new gasket. Technician B says that most gaskets should be lubricated with oil before installation. Who is correct?
a. A only
Technician A says that the timing chain cover seals oil in. Technician B says the plastic timing belt covers can be left off if they crack during removal. Who is correct?
a. A only
Technician A says that the valve guide must be clean and not worn excessively before repairing valve seats. Technician B says to pick a guide pilot that slides down to the bottom of the guide easily. Who is correct?
a. A only
Technician A says that when the thermostat opens coolant flows through the r radiator. Technician B says that thermostats usually last the life of the engine. Who is correct?
a. A only
Technician A says that you can use a chemical dye and a black light to pinpoint the cause of an oil leak. Technician B says to put 80 psi of air pressure in the dipstick tube and check for leaks. Who is correct?
a. A only
Technician A says that you should wear Z-87.1 safety glasses while working on or under vehicles.Technician B says that if you are hammering on a component on the bench, you should take your safety glasses off so you can see it better.Who is correct?
a. A only
Technician A says the main bearings protect the crankshaft journals. Technician B says the camshaft lobes lift the pistons. Who is correct?
a. A only
Technician A says the pistons should come out the top of the block. Technician B says to drive on the edge of the piston skirt with a punch to remove the pistons. Who is correct?
a. A only
Technician A says to reverse the tightening sequence when loosening the cylinder head. Technician B says to loosen the main cap starting at the front of the engine and moving toward the rear. Who is correct?
a. A only
Technician A says torque-to-yield fasteners are used to provide a uniform clamping pressure. Technician B says the Technician B says the use of torque wrenches is only for the inexperienced technician to be used as a learning tool. Who is correct?
a. A only
While discussing V8 crankshafts, Technician A says that a crate engine built for a vehicle with an automatic transmission may have a different crankshaft than the same one built for a manual transmission. Technician B says that a flat plane crankshaft is heavier and takes up more space than a cross plane crankshaft. Who is correct?
a. A only
While discussing turbocharger performance: Technician A says that worn turbocharger seals can cause blue smoke from the exhaust. Technician B says that a stuck-open wastegate can cause blue smoke from the exhaust. Who is correct?
a. A only
In a two-stroke cycle engine:
a. A power stroke is produced every crankshaft revolution.
The quietest timing mechanism is the:
a. Belt
What preparation must be done to the valve guides before measuring valve seat runout?
a. Clean the valve guide with a bore brush.
In order, the "3Cs" of a repair order are:
a. Concern, cause, correction
Engine components may be cracked by:
a. Extreme temperature changes in a very short time
All of the following drivability and engine problems may be caused by an intake manifold vacuum leak EXCEPT:
a. Low engine operating temperature
When bearing oil clearances are too large:
a. Oil pressure will be reduced
When running a vehicle on propane, engine wear is greatly reduced because:
a. Propane is a cleaner fuel.
A rubber engine mount has voids to make the mount:
a. Softer
A likely cause of low oil pressure is:
a. The oil pressure relief valve sticking open
A supercharger typically uses ____ to pressurize the intake charge.
a. Two rotors
An engine produces the following compression pressures: cylinder number one, 95 psi; cylinder number two, 140 psi; cylinder number three, 145 psi; cylinder number four, 135 psi. When a wet test is performed on cylinder number one, the pressure rises to 160 psi. The most likely cause of the problem with cylinder number one is:
a. Worn rings
When a vacuum gauge is connected to the intake manifold, the gauge needle fluctuates between 15 and 20 inch Hg (381 mm Hg) The cause of this problem could be
a. sticking valve stems and guides.
The advantages of the pentroof combustion chamber include each of the following EXCEPT:
b. A high S/V ratio
The engine is often described as a(n):
b. Air pump
A compression test is performed on an engine that is misfiring. All the pressures are between 175 psi and 185 psi except cylinder number five; it is 80 psi. Technician A says a valve seal could be bad. Technician B says the rings could be worn or broken. Who is correct?
b. B only
Air filter service is being discussed. Technician A says the air gun should be held tight against the air filter element when blowing dirt out of the filter. Technician B says when the outside of the air filter is observed with a trouble light inside the filter, small holes in the filter indicate filter replacement is required. Who is correct?
b. B only
An engine with 135,000 miles is running poorly. The cause of low compression on the third cylinder is being diagnosed using a cylinder leakage test. The results show 55 percent leakage. Most of the leakage is past an intake valve, but there is significant air coming out the oil fill port.Technician A says that he would replace the bad valve.Technician B says that he would recommend an engine overhaul or replacement.Who is correct?
b. B only
Increasing the compression ratio of an engine is being discussed. Technician A says increased compression ratios result in a reduction of power produced. Technician B says higher compression ratio engines require higher octane gasoline. Who is correct?
b. B only
One weak cylinder is found during a power balance test.Technician A says it could be caused by a plugged fuel filter.Technician B says it could be caused by a bad fuel injector. Who is correct?
b. B only
Technician A says a stuck-open oil pump relief valve can cause higher than normal oil pressure. Technician B says that worn oil pump gears can cause low oil pressure. Who is correct?
b. B only
Technician A says that a new or freshly rebuilt engine will run at higher engine temperatures during the break-in period. Technician B says that you should check oil pressure during the break-in period. Who is correct?
b. B only
Technician A says that during the first road test, you should accelerate and decelerate to full throttle several times to maximize oil pressure. Technician B says that after the road test, you should put the vehicle back up on the lift and make a final check for fluid leaks. Who is correct?
b. B only
Technician A says that generally a timing chain is replaced every 60,000 or 90,000 miles. Technician B says that typically the timing chain is replaced during a major engine overhaul. Who is correct?
b. B only
Technician A says that you can remove the valve stem from the Schrader valve to drain the fuel from the fuel rail.Technician B says to install a pressure gauge to drain the fuel from the fuel rail.Who is correct?
b. B only
Technician A says that you should spray head gaskets with copper sealer before installation.Technician B says that most head gaskets have a top marking on them.Who is correct?
b. B only
Technician A says the machinist's rule offers more precise measurements than a micrometer. Technician B says a dial indicator can be used to measure movement. Who is correct?
b. B only
Technician A says the piston is connected to the crankshaft by the rocker arm. Technician B says the connecting rod converts the reciprocating motion of the piston to the rotary motion of the crankshaft. Who is correct?
b. B only
Technician A says the timing chain is removed before the tensioner. Technician B says that to install the tensioner, you have to lock the plunger into the body. Who is correct?
b. B only
Technician A says to disconnect the positive battery cable first and then the negative cable. Technician B says to disconnect the negative battery cable first. Who is correct?
b. B only
Technician A says to let the engine idle for the first 15 minutes of operation after a rebuilt engine is installed.Technician B says that the oil should be changed after 500 miles of service on the rebuilt engine.Who is correct?
b. B only
To use an extractor, Technician A says to drill a hole into one side of the bolt. Technician B says to tap the extractor into the hole and turn it counterclockwise. Who is correct?
b. B only
While discussing volumetric efficiency: Technician A says volumetric efficiency is not affected by intake manifold design.Technician B says volumetric efficiency decreases at high engine speeds. Who is correct?
b. B only
The "greenhouse gas" that contributes to global warming is:
b. CO2
Forged engine components have these advantages and applications:
b. Crankshafts may be forged.
Each of the following is a common type of piston, EXCEPT:
b. Forged steel
The manufacturing process that yields the strongest finished part is:
b. Forging
When discussing propane, which statement is true?
b. Propane has more available energy.
When discussing exhaust manifold connections, each of the following statements is true EXCEPT:
b. Some exhaust manifolds are sealed with RTV.
All of these statements about head gaskets are true EXCEPT:
b. The core is usually made from silicone.
Misfire means:
b. The cylinder does not fire
The most common type of engine installation in a front-wheel-drive vehicle is:
b. Transverse
Valve timing affects each of the following EXCEPT:
b. Water pump
A technician is performing a starter current draw test because the engine will not turn over. The test results indicate that the current draw on the starter is higher than the specification. This means that the:
b. engine may be hydrostatically locked.
An engine should develop ____ in. Hg vacuum at idle.
c. 18
The most common refinishing valve face angle is:
c. 45°
Technician A says that a turbocharger may spin at speeds of 100,000 rpm. Technician B says that oil coking is a common cause of turbocharger failure. Who is correct?
c. A and B only
An engine produced the following compression pressures: cylinder number one, 150 psi; cylinder number two, 55 psi; cylinder number three, 45 psi; cylinder number four, 145 psi. Which is the most likely cause?
c. A blown head gasket
Flexible fuel vehicles use a fuel sensor that detects ____ so the PCM can better calculate spark timing and fuel delivery.
c. Alcohol content
A bolt will not loosen: Technician A says to tighten the bolt slightly. Technician B says to rap the head of the bolt. Who is correct?
c. Both A and B
A cooling system is pressurized with a pressure tester to locate a leak. After 15 minutes, the tester gauge has dropped from 15 psi to 5 psi, and there are no visible leaks in the engine compartment.Technician A says that the engine may have an internal head gasket leak.Technician B says that the heater core may be leaking.Who is correct?
c. Both A and B
Installing guide inserts is being discussed. Technician A says to measure the amount the guide protrudes from the head casting so the new guides can be installed to the same height. Technician B says to cut a chamfer on the insert if the insert does not have one. Who is correct?
c. Both A and B
Mechanical lifters require:
c. Both A and B
Technician A says a small-hole gauge can be used to measure the bore of a valve guide. Technician B says a valve guide bore gauge can be used to measure the bore of a valve guide. Who is correct?
c. Both A and B
Technician A says after a timing mechanism replacement you need to rotate the engine two complete revolutions to make a final check of the timing marks. Technician B says you should always road test a vehicle after a timing mechanism replacement. Who is correct?
c. Both A and B
Technician A says mechanical efficiency is a comparison between brake horsepower and indicated horsepower.Technician B says volumetric efficiency is a measurement of the amount of air-fuel mixture that actually enters the combustion chamber compared to the amount that could be drawn in. Who is correct?
c. Both A and B
Technician A says on some engines valve stem seals can be replaced without removing the head.Technician B says rocker arms can affect valve lift.Who is correct?
c. Both A and B
Technician A says that a VVT system may increase the overlap at higher rpm. Technician B says that a VVT system may retard the intake timing under heavy-load, high rpm conditions to improve power. Who is correct?
c. Both A and B
Technician A says that a front-wheel-drive engine may be removed from the top through the hood opening. Technician B says the transaxle may have to be removed with the engine on a front-wheel-drive vehicle. Who is correct?
c. Both A and B
Technician A says that a machine shop's inventory is high compared to other automotive repair shops. Technician B says that there are very few machines at new car dealerships. Who is correct?
c. Both A and B
Technician A says that a weak spring can cause valve float.Technician B says a weak valve spring can cause the valve to burn. Who is correct?
c. Both A and B
Technician A says that a worn-out valve guide will provide an inaccurate valve seat runout measurement.Technician B says that the valve seat-to-face contact area provides a path for heat from the valve head to dissipate.Who is correct?
c. Both A and B
Technician A says that an HEV uses a smaller gas engine than the conventional model vehicle.Technician B says that some parallel HEVs can use the electric motor(s) to boost the power of the gasoline engine. Who is correct?
c. Both A and B
Technician A says that core plugs are generally replaced during a high-mileage overhaul.Technician B says that oil galleries should be blown out with an air gun to clean them.Who is correct?
c. Both A and B
Technician A says that correcting valve stem height can correct rocker geometry. Technician B says that using different pushrods can correct rocker geometry. Who is correct?
c. Both A and B
Technician A says that high-voltage cables on all hybrid vehicles can be identified by their orange-colored insulation.Technician B says some hybrid vehicles' high-voltage systems remain powered up even with the engine off.Who is correct?
c. Both A and B
Technician A says that hydrocarbon emissions typically increase when an engine misfires.Technician B says that low compression can cause misfire. Who is correct?
c. Both A and B
Technician A says that it may be a shop policy to install a remanufactured engine rather than overhaul an engine in-house.Technician B says that some engines are damaged badly enough that it is not cost-effective to repair them. Who is correct?
c. Both A and B
Technician A says that the VIN can be used to identify the engine. Technician B says that a TSB may provide updated service information. Who is correct?
c. Both A and B
Technician A says that the more air an engine can take in, the more power it can put out. Technician B says that the exhaust can affect how well an engine can breathe. Who is correct?
c. Both A and B
Technician A says that the radiator should be cleaned or replaced after an engine overhaul. Technician B says to replace the water pump after an engine overhaul. Who is correct?
c. Both A and B
Technician A says that the repair order is a legal document.Technician B says that the repair order should be used as a communication tool with the customer.Who is correct?
c. Both A and B
Technician A says that the technician will complete the "cause" section of the repair order.Technician B says that the technician may have to communicate with the customer to find the problem? Who is correct?
c. Both A and B
Technician A says that timing belts are quieter than timing chains. Technician B says that timing chains generally last longer than timing belts. Who is correct?
c. Both A and B
Technician A says that writing the repair order is usually the first step in repairing a vehicle.Technician B says that the repair order is a legal document. Who is correct?
c. Both A and B
Technician A says that you often need to remove the radiator before removing the engine. Technician B says to drain the coolant from the engine block as well as from the radiator. Who is correct?
c. Both A and B
Technician A says to check compression before disassembling an engine. Technician B recommends performing a compression test before completing a major maintenance service if the engine is running very badly. Who is correct?
c. Both A and B
Technician A says to lift vehicles by the front and rear frames.Technician B says that some vehicles will permanently twist if lifted improperly.Who is correct?
c. Both A and B
Technician A says to mark the main caps before disassembly.Technician B says that if main caps are installed in the wrong direction, the crankshaft could seize.Who is correct?
c. Both A and B
Technician A says to measure the amount of out-of-round of a cylinder, measure the bore in three directions at the same bore depth. Technician B says when measuring the bore, subtracting the smallest reading from the largest, at the same bore depth, will provide the amount of the out-of-round. Who is correct?
c. Both A and B
Technician A says to measure valve installed height when reassembling the cylinder head. Technician B says to shim the valve springs if the valve installed height is below specifications. Who is correct?
c. Both A and B
Technician A says to rotate the engine to TDC number 1 before removing the timing mechanism. Technician B says to make a mental or written note of the location of the timing marks. Who is correct?
c. Both A and B
Technician A says to try to take as much material off the valve stem tip as you did off the face. Technician B says you should put a light chamfer on the tip. Who is correct?
c. Both A and B
Technician A says to use a socket or a box-end wrench to loosen tight bolts. Technician B says to use locking pliers to free up rusted bolts. Who is correct?
c. Both A and B
Technician A says valve head runout can be checked with the valve in the valve machine. Technician B says a total indicated reading (TIR) greater than 0.002 inch (0.05 mm) on the valve head requires valve replacement. Who is correct?
c. Both A and B
While discussing the proper way to lift a heavy object:Technician A says that you should bend at your knees if you are going to pick up a heavy object. Technician B says that if the object is too heavy, then a wheel dolly should be used. Who is correct?
c. Both A and B
The crankshaft is balanced by the ____ to overcome the weight of the rod journal, piston pin, connecting rod, and piston.
c. Counterweights
A restricted exhaust system can cause:
c. Loss of power
A spark plug gap that is too wide can cause:
c. Misfire
Each of the following is a toxic pollutant created by the automobile, EXCEPT:
c. N2
Each of the following is part of a typical valvetrain, EXCEPT:
c. Ports
The fire ring in a head gasket:
c. Protects the gasket material from high combustion temperatures
Aluminum blocks often use:
c. Steel liners
Each of the following is a crankshaft material, EXCEPT:
d. Forged aluminum
Each of the following is a likely cause of detonation EXCEPT:
d. Fuel with too high an octane rating
Each of the following is a likely cause of detonation EXCEPT:
d. Fuel with too high of an octane rating
An automatic timing belt tensioner:
d. Is filled with silicone oil
The most common type of engine installation in a rear-wheel-drive vehicle is:
d. Longitudinal
An engine has 45 percent leakage, and air is heard at the intake manifold. Technician A says the rings are bad. Technician B says the engine should run fine. Who is correct?
d. Neither A nor B
An exhaust manifold with an HO2S sensor is cracked upstream from the sensor. Technician A says this condition does not affect the HO2S sensor signal. Technician B says this condition will damage the HO2S sensor. Who is correct?
d. Neither A nor B
Engine measurement is being discussed. Technician A says the bore is the distance the piston moves within the cylinder.Technician B says the stroke is the diameter of the cylinder. Who is correct?
d. Neither A nor B
Technician A says that advanced camshaft timing will increase power at high RPM. Technician B says that retarded camshaft timing will increase power at low RPM. Who is correct?
d. Neither A nor B
Technician A says that most engines are timed at BDC of the compression stroke for cylinder number 1.Technician B says that valve timing should be adjusted every 60,000 miles.Who is correct?
d. Neither A nor B
Technician A says that oil pressure increases as temperature increases. Technician B says that oil pressure decreases as engine speed increases. Who is correct?
d. Neither A nor B
Technician A says that some machines can be routinely used beyond their stated capacity. Technician B says that a power tool can be left running unattended if the technician puts up a power "on" sign. Who is correct?
d. Neither A nor B
Technician A says that when you are installing a crate engine, you will usually install a new water pump if one does not come with the engine. Technician B says that you will need to swap components such as sensors and actuators. Who is correct?
d. Neither A nor B
While discussing pistons, Technician A says the larger diameter of a cam ground piston is across the piston pin bores. Technician B says pistons are manufactured with a perfectly vertical skirt. Who is correct?
d. Neither A nor B
Each of the following is a function of the lubrication system, EXCEPT:
d. Provides oil pressure to the piston pins
Where would you typically find an "assembly line" for engine rebuilding?
d. Remanufacturing facility
A harmonic balancer has separated. The response the technician should take is:
d. Replace the whole harmonic balancer.
Which of the following is true?
d. The crankshaft rotates twice as fast as the camshaft.