AT101 MCQ
cast iron has about how much carbon content
3%
To lower and narrow a valve seat that has been cut at a 45-degree angle, use a cutter or stone of what angle?
30°
How many degrees of camshaft rotation are needed to complete the four stroke combustion cycle?
360
a DOHC V-6 has how many camshafts?
4
Valve spring inserts (shims) are designed to ___
Adjust the correct valve spring installed height
All overhead valve engines _________ .
Have the valves located in the cylinder head
Where is a multilayered steel (MLS) gasket most often used in an engine?
Head gasket
ultrasonic testing is used to test
cylinder wall thickness
siamese cylinder bores are
cylinders with no coolant passage between them
the block deck is the
top surface of the block
the thrust bearing surface is located on one of the main bearings to control thrust loads caused by ____
torque converter or clutch release forces
if lift and duration remain constant, lobe center angle decreases, ______
valve overlap increases
What are the classes of fire extinguishers?
Class A - General combustibles (cloth, paper, wood) Class B - Flammable liquids and greases (gasoline, oil, thinners, solvents) Class C - Electrical fires Class D - Combustible metals (powdered aluminum, sodium, magnesium)
Bearing ______ occurs when a bearing shell is slightly above the parting surface of the bearing cap.
Crush
The proper relationship between intake and exhaust valve diameter is ___
Exhaust valve size is 85% of intake valve size
Umbrella type valve stem seals ___
Fit tightly onto the valve stem
Horsepower is expressed in units of ___________ .
Foot-pounds per minute
What force causes a head gasket to be drawn downward during engine operation?
Intake stroke vacuum
which of the following is the most correct statement about the direction of engine rotation?
Most engines rotate clockwise as viewed from the front of the engine
some manufacturers recommend repairing integral guides with
OS stem valves
How many rotations of the crankshaft are required to complete each stroke of a four-stroke cycle engine?
One-half
The intake valve opens at 39 degrees BTDC and closes at 71 degrees ABDC. The exhaust valve opens at 78 degrees BBDC and closes at 47 degrees ATDC. Which answer is correct?
Overlap = 86°
Torque is expressed in units of ___________ .
Pound-feet
Dampers (damper springs) are used inside some valve springs to ___
Prevent valve spring surge
How to jump start a vehicle with a dead battery
Step 1. Bad car + Step 2. Good car + Step 3. Good car - Step 4. Bad car engine block or metal bracket on engine block.
What determines the stroke of an engine?
The shape of the crankshaft
piston ring gap should only be measured after
all cylinder work is done
Use new pushrods because ______
all the dirt cant be cleaned out the hollow center
A steel or copper wire used in a head gasket around the cylinder is called ___ .
armor fire ring
cast iron cylinder sleeves are either cast into the aluminum block during manufacturing or pressed into the aluminum block. These sleeves are not in contact with the coolant passages and are called _______ .
dry cylinder sleeves
A typical v-8 engine crankshaft has ___ main bearings.
five
if bearing to journal clearance is doubled how much oil will flow?
four times the amount
a gasket failure caused by the movement of dissimilar materials is
fretting
a splayed crankshaft ___
has offset rod journals
cylinder heads with four valves flow more air than those with two valves because they
have a greater open area increase the velocity of the air
If an engine at sea level produces 100 hp, how many horsepower would it develop at 6000 ft of altitude?
hp @ elevation = hp @ sea level - (0.03*elevation*hp@sea level)/1000 hp @ 6000 ft = 100 - (0.03*6000*100)/1000 = 82 hp
what other engine component may have to be machined if the cylinder heads are machined on a V-type engine?
intake manifold
which type of valve guide is most used in a cast-iron head?
integral
which type of connecting rod needs to be heated to install the piston pin?
interference fit
full floating piston pins are retained by
lock rings
what should be installed and torqued to factory specs before machining a block
main bearing caps should be installed and torqued to factory specs before machining a block
The purpose of casting steel struts into an aluminum piston is
more strength control thermal expansion
which timing chain type is also called a "silent chain"?
morse flat link
side clearance is a measure taken between the
piston ring and piston ring groove
if a crankshaft is ground, it must be ____
polished
some gaskets use a steel washer around each bolt hole. the purpose of this washer is to ___ .
prevent the gasket from being overly compressed
which component is not needed in a typical overhead cam engine
push rod
a warped aluminum cylinder head can be restored to service by
put in 500°F oven with shims under each end, cool it, machine it
which product requires no heat to remove?
red thread locker
cam ground pistons, as they warm up, take on which of these shapes?
round
which type of sealer is to be used on nonmachined surfaces?
rtv
engine blocks can be manufactured using which methods
sand cast or die cast
A hypereutectic piston has a higher
silicon content
a full-floating piston pin is held in place using
snap rings
a one piece oil pan gasket often uses ___ in the middle to add strength
steel
flat bottom valve lifters rotate during operation because of the ______ of the camshaft
taper of the lobe
technician a says that if the ring end gap is excessive, blowby gases can travel past the rings and into the crankcase. technician b says that piston rings usually include three compression rings at the top of the piston and an oil control ring below the compression rings. who is right?
technician a only
which type of oil seal must not have oil applied for it to work correctly?
teflon
which statement is true about surface finish
the rougher the surface, the higher the microinch finish measurement
the surface finish for the cylinder walls usually depends on
the type of piston rings to be used
Hydraulic lifters can make a ticking noise when running if _____
the valve lash is too loose
hydraulic lifters or lash adjusters (HLA) may not bleed down well and cause an engine miss if ______ .
the wrong sae rated engine oil is used
audi five valve
three intake two exhaust
When measuring a cylinder for wear, the most wear will be found at the
top of the cylinder
The block deck is the
top surface of the block
In a normally operating engine, intake and exhaust valves are opened by a cam and closed by ________.
valve springs
vvt intake and exhaust
vvt intake - increase low speed torque vvt exhaust - reduce exhaust emissions
Technician A says that a crankshaft determines the stroke of an engine. Technician B says that the length of the connecting rod determines the stroke of an engine. Which technician is correct?
✓ X A
a misaligned connecting rod causes what type of engine wear?
diagonal wear on the piston skirt
typical bearing to journal clearance is
0.0005" to 0.0025"
typical valve stem to guide clearance is
0.001 - 0.004 " (0.03 - 0.05 mm)
A valve seat should be concentric to the valve guide to a maximum TIR of ___.
0.002 in
cylinder head gasket surface variation as measured with a precision straightedge
0.002" in any 6" length 0.004" overall
Never remove more material from the tip of a valve than
0.020
a valve should be discarded if the margin is less than ___ after refacing
0.03
If an interference angle is machined on a valve or seat, the angle is usually ________.
1 degree
Many aluminum piston skirts are plated with
Tin or moly graphite
A rotating force is called ____________ .
Torque
Compression Test
1. Remove fuel pump and fuel-injection fuses. Disconnect main wire to coil and spark plug wires. Remove spark plugs. 2. Thread compression gauge in a spark plug hole. 3. WOT, crank 4 times. This should result in a stable reading. If not, crank up to 10 times, but do the same for each cylinder. 4. Note readings for each cylinder
the camshaft makes ______ per crankshaft revolution
1/2 revolution
How many degrees of CAMSHAFT rotation are needed for a piston to travel from TDC to BDC and return to TDC
180
a four cylinder engine fires a cylinder every ______ degrees of crankshaft rotation
180
A normally aspirated automobile engine loses about ____________ power per 1,000 ft of altitude.
3%
One cylinder of an automotive four-stroke cycle engine completes a cycle every _____________ .
720 degrees
The coolant flow through the radiator is controlled by the _____________ .
Thermostat
An SOHC V-8 engine has how many camshafts?
Two
A hypereutectic piston
Uses about 16% silicon Is a cast piston
What are the types of fire extinguishers and their usage?
Water - class A fires Carbon dioxide - class B or C fires Dry chemical - Class A, B or C fires
technician a says that the connecting rods should be marked before disassembly. technician b says that pistons are cam ground so that when operating temperature is reached, the piston will have expanded enough across the piston pin area to become oval shaped. who is right?
a
two technicians are discussing a hemi engine. technician a says that a hemi is an engine with a hemispherical-shaped combustion chamber. technician b says that all hemi engines are cam-in-block designs. which technician is correct?
a
A forged crankshaft has a _______ .
Wide parting line
Technician A says that replacement pistons can be of different weights from the original pistons. Technician B says that some engines use an offset piston pin to help reduce piston slap when the engine is cold. Who is right?
X ✓ B
technician a says that the block deck is the surface to which the cylinder head attaches and can be slightly concave-shaped. technician b says that core plugs are used to fill the holes in the block used for casting. who is right?
X ✓ B
the space behind the piston ring is called
back clearance
a bearing shell has a slightly larger arc than the bearing housing. this difference is called _____
bearing spread
a bedplate is located between the
bottom of the block and oil pan
the ratio of the volume of a cylinder with the piston at BDC to the volume of the cylinder with the piston at TDC is known as ____
compression ratio
which component listed below does not form part of the combustion chamber
connecting rod
the ________ converts linear motion of the pistons into rotary motion
crankshaft
a ______ can be installed in a cast iron block to repair a worn or cracked cylinder
cylinder sleeve
