Basic Engines
Tech A says that Corporate Average Fuel Economy (CAFE) standards govern vehicle emissions. Tech B says that CAFE standards govern fuel economy. Who is right?
B
Tech A says that most rear wheel drive cars have a transaxle. Tech B says that front wheel drive cars have two driveshafts. who is right?
B
What is the purpose of the cam shaft?
It opens and closes the valves.
Tech A says that an ignition spark is 12 volts. Tech B says that the spark happens just after the power stroke begins. Who is right?
Neither
Tech A says that model t's were all black. Tech B says that the 12 volt electrical system has been standard on American cars since 1940. who is right?
Neither
How many cam shaft revolutions are required to fire all the cylinders in a four stroke engine?
One
What does OHC mean?
Over Head Cam
the starter motor pinion gear drives the __________ gear on the crankshaft's flywheel?
Ring
what is the name of the patent for the automobile?
Selden patent
The parts of a computer control system that react to temperature, airflow, engine load, road speed, and oxygen content in the exhaust system are called?
Sensors
what is the term for an engine block assembly that is sold without cylinder heads?
Short block
Name four types of taps?
Tapper, plug, bottom, pipe
what is volumetric efficiency?
The ability of the engine to breathe
What components determine the firing order?
The cam and crank shaft.
If an engine with companion cylinders, if one piston is on an exhaust stroke, what stroke is the companion on?
The companion cylinder is up.
What is compression ratio?
The difference between bottom dead center and top dead center.
how many radial lines does an SAE grade 8 bolt have on its head?
6
to what percent of its elastic limit is a bolt usually toequed?
70%
What is the formula used to calculate the degrees of the crankshaft rotation between power strokes?
720 degrees / the number of cylinders.
what is mechanical efficiency on a gasoline?
90%
tech A says that a nonhardened nut loses clamping ability each time it is retorqued. Tech B says that a cap screw loses clamping ability each time it is retorqued. who is right?
A
tech A says that the intake valve is open during part of the compression stroke. tech B says that the exhaust valve is open during part of compression stroke. who is right?
A
What is the difference between a cycle and a stroke?
A cycle is a completion of all four strokes.
the valve is opened by a _________ on the camshaft?
A lobe
What is the formula used to calculate cubic inch displacement?
4 squared x stroke x .7854 x # of cylinders
when an engine is running at 6,000 rpm; how many times does each valve open and close every second?
50
Refer to a tap drill size chart. What is the correct tap drill for 1/4 x 20 screw thread?
7
the air fuel ratio on gasoline engines ranges from?
12:1 to 15:1
what is practical efficiency on a gasoline engine?
15%
What are companion cylinders?
2 cylinders that move from top dead center to bottom dead center together.
what is thermal efficiency on a gasoline engine?
33%
Tech A says that a steam engine is an external combustion engine. Tech B says that a four stroke engine is an internal combustion engine. who is right?
Both
Tech A says that gears are changed to increase or decrease engine torque. Tech B says that the majority of new cars have automatic transmissions. who is right?
Both
Tech A says that the crankshaft turns 720 degrees during one four stroke cycle. tech B says that the camshaft turns 360 degrees during on cycle. who is right?
Both
tech A says that the oil pump is sometimes driven by the camshaft. Tech B says that the distributor is sometimes driven by the camshaft. who is right?
Both
Tech A says that the intake valve is closed during the compression stroke. Tech B says that the exhaust valve is closed during the compression stroke. Who is right?
Both A and B
If you know the CID how do you calculate the engine size in liters?
CID divided by 61.024
what cutting lubricant, if any, is used when cutting cast iron?
Can be cut dry
besides spring pressure what forces the piston ring against the cylinder wall?
Combustion
the air fuel mixture is ________ as the piston moves up on the compression stroke?
Compressed
what does reciprocating mean?
Continuous up and down motion of the piston
what is another name for antifreeze?
Coolant
Which of the following is true about camshafts? A. the camshaft on a typical six cylinder pushrod engine has 12 cam lobes. B. the crankshaft sprocket has half as many teeth as the camshaft sprocket. C. older engines had an extra eccentric lobe to operate a mechanical fuel pump. D. all of the above
D
which of the following is true about intake and exhaust valves? A. exhaust valves are larger then intake valves B. intake valves open against higher pressure than exhaust valves. C. Both D. Neither
D
which of the following is true about fuel systems? A. fuel injection has replaced the carburetor on modern engines. B. fuel injection provides for more accurate control of exhaust emissions. C. to burn, gasoline must be mixed with air to form a vapor. D. All of the above
D.
one way drills are classified is by fractions. What are the other two methods?
Decimals, letter, and number
what is true about diesel engines?
Diesel timing is controlled by when the fuel is injected into the cylinder.
what is the name of the machine shop process that erodes a broken fastener without damaging the screw thread?
Electrical discharge machining
In what type of engines are companion cylinders found?
Even number multiply four stroke engines.
If a nut turns easily for a few threads on a bolt and then begins to turn only with difficulty, what could be the problem?
Fastener is stretched
What are the three degrees of bank on a six cylinder v-type engine?
Fifteen, thirty, sixty, and ninety degrees.
when air and fuel are compressed they become?
Flamable
From what position on the engine is the right and left bank determined on a v-type engine?
From the back of the motor of fly wheel.
How fast does the cam shaft turn in relation to the crank shaft and how is this accomplished?
Half as fast as the crank shaft and is geared down.
List the factors affecting compression ratio?
Head gasket, piston, dome size, combustion chamber volume, and deck clearance.
what is one of the trade names for a replacement thread insert?
Heli coil keensert, slimsert
what is the difference between horsepower and torque?
Horsepower is the ability to perform work
what is the purpose of casting and forging numbers on a cylinder block or head?
Identification
What are the 3 different types of four stroke reciprocating gasoline engines?
In-line, V-type, and Horizontally opposed
What is the purpose of the valves?
Intake lets air and fuel in and the exhaust allows gas to escape.
Name the four events on a four stroke engine.
Intake, compress, power, and exhaust.
List the four strokes of the four stroke cycle in order?
Intake, compression, power, and exaust
Which direction is the piston moving during each of the strokes?
Intake=down, Compression=up, Power=down, Exhaust=up
What is the purpose of the crank shaft?
It changes reciprocating motion to rotary motion.
What is not true about a four stroke gasoline engine?
It is a compression ignition engine
What valve is hotter?
The exhaust valve.
What valve is larger?
The intake valve.
what is the purpose of a flat rate manuel?
To determine the amount of time to do a job
How many crank shaft revolutions are required to fire all the cylinders in a four stroke engine?
Two
what is the name of the automotive chassis design that has a floor pan and a small subframe section in the front and rear?
Unibody
what is another name for the harmonic balancer?
Vibration damper
What is the purpose of valve overlap?
Volumetric efficiency.
What is valve overlap?
When both valves are open at the same time
the movement of the piston from TDC to BDC is called?
a stroke
The _______ allows the rear wheels to rotate at different speeds as the vehicle goes around corners?
differentals
which valve is usually not magnetic?
exhaust
tech A says that the "20" in 1/4 x 20 signifies the total number of threads the fastener has. tech B says that the "1/4" signifies the socket size of the fastener head. who is right?
neither
name one place where pipe threads are found in an engine?
on pipe plugs and sending units
How many times does each valve open during a 720 degrees of crankshaft rotation?
once
what are the names of the parts that seal the combustion gases between the piston and the cylinder?
piston rings
if there is to much clearance between the piston and the cylinder wall, what happens?
piston slap
what do the top two piston rings do?
seal compression
what is the name of the butterfly valve that controls the amount of air entering the engine?
throtle
Why is a tap turned backwards after turning forward when cutting a thread?
to break the metal chips