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67 Cards in this Set
- Front
- Back
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What is the four stroke cycle?
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Intake, compression, power, exhaust
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What happens in the intake stroke?
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Air/Fuel mixture enters the combustion chamber.
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What happens in the compression stroke?
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Air/Fuel mixture is compressed.
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What happens in the power stroke?
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Air/Fuel is ignited by spark plug.
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What happens in the exhaust stroke?
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Burned Air/Fuel gases are forced out of the combustion chamber.
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What is the Air/Fuel mixture ratio?
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14.7 to 1 for gas mixture.
Varies for the diesel engine depending on how much fuel is injected |
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What is the ignition method for gas?
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Spark
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What is the ignition method for diesel?
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Compression
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What is the funtion of the supercharger?
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Enhances engine horsepower by forcing more air in to the cylinders.
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What drives the supercharger?
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A belt driven by the crankshaft.
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What controls the output of the supercharger?
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ME control module through an electromagnetic clutch.
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What is the maximum charge pressure for the 112 engine?
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1100 mbar.
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What is the function of the turbo charger?
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Enhances engine output by forcing more air in to the cylinders.
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Where is the location of the turbo charger?
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Normally located on the exhaust manifold of all engines.
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What drives the turbo charger?
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Exhaust gases.
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What controls the turbo charger output?
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ME control module.
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What is the purpose of the intercooler?
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Cools the air heated up by the compression during intake.
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Where is the intercooler located?
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Below the radiator.
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How can engine breathing be enhanced?
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Tuning the intake manifolds to optimize the pressure pulses in the intake system.
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What is used to increase the efficiency of the intake manifold and broaden the torque range?
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Variable Runners.
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In variable runners where is the air directed at low RPM's?
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The long runners, to increase the airs velocity.
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In variable runners where is the air directed at high RPM's?
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The short runners, to increase the volume of the incoming air
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At high engine load and low rpm the flaps are?
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Closed, directing air into the long runners.
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At higher rpm the flaps are?
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Opened, directing air in to the short runners.
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What two engines have swirl flaps?
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272 and 648
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What three engines have variable intake runners?
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112, 113, 272
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What is the purpose of swirl flaps?
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Improve air/fuel mixture constancy.
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Which engine has a intake manifold with integral vacuum reservoir?
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272
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Exhaust valves are usaully smaller in diameter then intake valves except in...?
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Three valve engines like the M112 and M113.
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Exhaust valves are filled with sodium to...?
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Absorb heat and reduce thermal load on valve.
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What two engines have three valves per cylinder?
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112 and 113
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What two engines have four valves per cylinder?
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272 and 648
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At what speed does the camshaft turn?
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One half the crankshaft speed
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What two engines have the single overhead cam?
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112 and 113
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Which DOHC engine has the bearing caps integrated into the cylinder head cover?
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272
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What two engines use a dual overhead cams?
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272 and OM 648
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What is the combustion chamber formed of?
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The top of the piston and the cavity in the cylinder head.
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What is the specification for the compression test?
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12 - 15 bar, less then 1.5 bar between highest and lowest piston.
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What is the specification for the leak down test?
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Max cylinder leak of 25%
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What do you check when installing a timing chain?
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Camshafts are timed together.
Camshafts are timed to the crankshaft. Balance shaft is timed to the crankshaft. |
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What is the diesel injection pump driven by?
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Camshaft via a gear.
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What is variable valve timing?
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a method that advances or retards camshaft timing to improve engine performance and emissions.
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What engine uses variable valve timing?
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272 (273)
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What is the purpose of the damper?
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Reduces engine vibration.
Mounting surface for drive pulley. |
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What is the purpose of the balance shaft?
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Reduces engine vibration.
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What direction does the balance shaft rotate?
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Opposite of the crankshaft.
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What motors use a balance shaft?
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Some four cylinders and all V Six engines.
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What engines use a balance shaft?
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112 and 272
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Why doesn't the V8 use a balance shaft?
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The two additional power pulses make up for the degress of rotation where no rotational torque is applied.
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What technology creates a near perfect junction between the cap and the rod?
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Cracking
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What forms the walls of the combustion chamber?
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Cylinder bores
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What drives the oil pump?
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Crankshaft
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What creates pressure for the lubrication system?
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Oil Pump
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What is the oil specification at operating temperature?
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.7 bar at 700 rpm
3 bar at 3000 rpm |
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What does the suction fan do?
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Pulls air through the radiator to reduce coolant temperature.
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What commands the suction fan?
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ME SFI control module
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What inputs cause the suction fan to come on?
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AAC, CAAC, and coolant temperature sensor.
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What is the purpose of the auxiliary water pump?
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Ensures that water flows through the heater core uniformly, w/o bubbles, even at low speeds.
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What are the recommended coolant mixtures?
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50/50 or 45/55
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What degree are the ring gaps staggered at?
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120 degrees
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When must the connecting rod bolts be replaced?
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If they are longer then specified.
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How long do the spark plugs last in a 112/113 engine?
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5 years/91,000 miles
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How long do spark plugs last in a 272 engine?
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5 years/78,000 miles
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How long does oil last?
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1 year/13,000 miles
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How long does the air filter last?
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4 years/52,000 miles
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How long does the coolant last?
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15 years/142,000 miles
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During an oil change when is the oil filter replaced?
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Before the oil is drained.
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