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Piston 1 - Week 4

What tool is used to check/measure/set valve clearance?

Vernier caliper

Feeler gauge

Micrometer

Screwdriver

Where is valve clearance measured?

Between the pushrod and the rocker arm

Between the tappet and the pushrod

Between the valve tip and the rocker arm

Between the camshaft and the lifter

What is the smooth area between cam lobes on a cam ring called?

Valve lift

Cam track

Dwell time

Duration

What is the equation for cam ring speed?

What is the most common type of valve used in aircraft piston engines

Poppet valve

Rotary valve

Sleeve valve

Slide valve

What is the purpose of the valve guide?

To closely fit and seal with the face

To hold the valve springs in the head

To control fuel flow into the manifold

To keep the face aligned with the seat

What is used to hold a valve in place?

Stem & valve guide

Nuts & bolts

Face & seat

Retainer & split key

What is the purpose of a rocker arm?

To change the lifting motion of the push rod into downward motion needed to open a valve

To create an up and down motion of the piston inside of the cylinder assembly

To force the intake valve open when the exhaust valve closes

To change the lifting motion of the camshaft lobe into downward motion needed to open a valve

What is used to open an intake or exhaust valve?

Crank, connecting rod, pin, piston

Cam, pusher, push rod and valve spring

The Force

Cam, lifter, push rod & rocker arm

Which of the following types of valve heads is used in an aircraft piston engine?

Mushroom head

Flat head

Turbo head

Convex head

How many degrees of intake valve lag in the following diagram?

60 degrees

25 degrees

30 degrees

15 degrees

What is the purpose of the intake valve?

To control the amount of air/fuel that leaves the cylinder

To control the amount of air/fuel that enters the cylinder

To control the amount of air that enters the cylinder

To control the amount of waste gases that leave the cylinder

What does valve overlap take advantage of?

Exhaust gas inertia & "pot-charging"

Exhaust gas inertia & "venting"

Intake gas inertia & "precharging"

Increased cylinder cooling

What does the term valve timing describe?

The points at which the intake and exhaust valves close during the 4-stroke cycle relative to crankshaft position

The points at which the intake and exhaust valves open & close during the 4-stroke cycle relative to camshaft position

The points at which the intake and exhaust valves open & close during the 4-stroke cycle relative to crankshaft position

The points at which the intake and exhaust valves open during the 4-stroke cycle relative to crankshaft position

What is it called when both intake and exhaust valves are open at the same time

Valve wear

Valve overlap

Turbocharging

Valve mismatch

What part of the valve joins the head and the stem?

Shaft

Face

Neck

Tip

What part of the valve keeps the head aligned properly?

Neck

Face

Stem

Tip

If valve clearance is out of specification what will be the end result?

The valves will not open completely

The valves will not close

The valves will not open completely or close fully

The valves will not work at all

When is it necessary to check valve clearance with hydraulic lifters?

Every time an oil change is completed

Any time a clattering noise is heard in the engine when starting

Every 100 hours or more according to the maintenance manual and the operating environment

Only when cylinders are replaced

What is the primary purpose of valve overlap?

Increasing turbocharger effectiveness

Increasing volumetric efficiency

Reducing cylinder temperatures

Reducing environmental emissions

How many degrees of crankshaft rotation is the intake valve open?

60 degrees

180 degrees

195 degrees

255 degrees

What is the purpose of the exhaust valve?

To control the amount of waste gases that leave the cylinder

To control the amount of air/fuel that enters the cylinder

To control the amount of air/fuel that leaves the cylinder

To control the amount of air that enters the cylinder

What are some exhaust valves filled with to improve valve cooing?

Inconel

Sodium chloride

Stellite

Metallic sodium

Which of the following types of valve heads is used in an aircraft piston engine?

Tulip head

Semi-convex head

Turbo head

Mushroom head

What kind of clearance check is typically done on an aircraft engine?

Cold clearance check

Operating clearance check

In-flight clearance check

Hot clearance check

What is used to hold the valve in the cylinder head?

Nut & lock wire

Split key

Bolt & lock wire

Nut & lock washer

What part of the valve forms the seal with the cylinder head?

Face

Stem

Neck

Tip

What is the purpose of using two valve springs for each valve

To speed valve opening

To prevent valve float

To speed valve closing

To reduce valve operating forces

How many times does the crankshaft rotate for a valve to open and close

Six times

One half revolution

Twice

Once

What is a cam ring?

The spring clip put onto valves in a radial engine to prevent the valve from falling into the cylinder it the valve split keys/springs fail

A forged zig-zag piece of steel with throws along it's length

A circular piece of steel with a series of cam lobes on it's inner edge

A circular piece of steel with a series of cam lobes on it's outer edge

How often do hydraulic lifters need valve clearance adjustment in normal operation?

Any time a clattering noise is heard in the engine when starting

Every 100 hours or more according to the maintenance manual and the operating environment

Never once they are put into service

Every time an oil change is completed

What is another name for a hydraulic lifter?

A flux capacitor

A low maintenance lifter

An alternate cycle valve actuator

A zero lash lifter

What is another name for a hydraulic lifter?

A low maintenance lifter

An alternate cycle valve actuator

A flux capacitor

A zero clearance lifter

What are the types of valve heads used in an aircraft piston engine?

Flat, semi-tulip, tulip

Flat, semi-tulip, mushroom

Flat, quarter-tulip, tulip

Flat, mushroom, tulip

Which of the following types of valve heads is used in an aircraft piston engine?

Semi-tulip head

Semi-convex head

Turbo head

Mushroom head

How many cam tracks will a cam ring have?

What is exhaust valve lag?

The number of degrees of crankshaft rotation that the valve closes before the piston reaches BDC

The number of degrees of crankshaft rotation that the valve opens after the piston reaches TDC

The number of degrees of crankshaft rotation that the valve closes after the piston reaches TDC

The number of degrees of camshaft rotation that the valve closes before the piston reaches BDC

What is the result if the valve lead/lag is incorrect

The engine's performance will go down due to the incorrect volumes of air/fuel/exhaust going into and out of the cylinder

The engine's performance will go up due to the incorrect volumes of air/fuel/exhaust going into and out of the cylinder

No change, the engine will perform as designed

The engine's performance will go up due to the increased volumes of air/fuel/exhaust going into and out of the cylinder

What is intake valve lead?

The number of degrees of crankshaft rotation that the valve closes after the piston reaches TDC

The number of degrees of camshaft rotation that the valve opens before the piston reaches TDC

The number of degrees of crankshaft rotation that the valve opens before the piston reaches BDC

The number of degrees of crankshaft rotation that the valve opens before the piston reaches TDC

What is the purpose of the "ramp" on each side of the cam lobes on a cam ring?

To make sure that each valve has the correct valve clearance at all points in the otto cycle

To reduce the initial shock of an abruptly rising lobe on the valve train

To reduce frictional losses in the valve train

To increase the speed that the valve opens at the beginning of each valve cycle

What is the purpose of using two valve springs for each valve

To reduce the probability of engine failure due to thermal expansion

To speed valve closing

To reduce valve operating forces

To reduce the probability of engine failure due to breakage

In a radial engine what component actuates the valve lifter?

The cam ring

The push rod

The rocker arm

The crankshaft

What is exhaust valve lead?

The number of degrees of crankshaft rotation that the valve opens before the piston reaches TDC

The number of degrees of camshaft rotation that the valve closes before the piston reaches BDC

The number of degrees of crankshaft rotation that the valve opens before the piston reaches BDC

The number of degrees of crankshaft rotation that the valve closes after the piston reaches BDC

What is the speed of a camshaft in a horizontally opposed engine compared to that of the crankshaft?

One half

Two times

Six times

The same

If a solid lifter is used in an engine what maintenance does the valve train require

Regular oil changes

Regular grinding of the valve tips to remove damage

Valve clearance checks and adjustments

Dry clearance checks at every inspection

What is the purpose of the camshaft?

The transform the circular motion of the crankshaft to linear motion to actuate a valve

To push/pull the pistons up and down in the cylinder assembly

The transform the circular motion of the piston to rotary motion to actuate a valve

To create an ignition event at the correct time in the otto cycle

How many times in the Otto cycle does a cylinder use valve lag?

How is valve clearance manually adjusted with hydraulic lifters?

By using adjusting screws and locks on the hydraulic lifters

By using adjusting screws and locks on the rocker arms

Valve clearance is never adjusted when using hydraulic lifters

By changing the push rods for ones with the correct length if out of specification

When is a dry-lifter clearance check performed?

Every 100 hours or more according to the maintenance manual and the operating environment

Any time a clattering noise is heard in the engine when starting

Every time an oil change is completed

Only when cylinders are replaced

What material is welded to the valves to make them more durable ?

Stellite

Nickel

Inconel

Tungsten steel

Which components are used to tightly seal the valves?

Lifters, push rods, rockers

Lifters, springs, spring retainers, seats

Valve guides, seats, springs, spring retainers

Valve guides, seats, springs, push rods

What is the purpose of a tappet?

To create additional lift over a portion of the wing during slow speed flight

To transmit the push/pull force of the camshaft to the push/pull rod

To push the piston up for compression & exhaust strokes

To transmit the lifting force of the camshaft to a pushrod

How many times does a cylinder utilize valve lead in the otto cycle?

What is intake valve lag?

The number of degrees of crankshaft rotation that the valve opens after the piston reaches TDC

The number of degrees of camshaft rotation that the valve closes after the piston reaches BDC

The number of degrees of crankshaft rotation that the valve closes before the piston reaches TDC

The number of degrees of crankshaft rotation that the valve closes after the piston reaches BDC

Where is valve clearance measured?

Between the tappet and the pushrod

Between the pushrod and the rocker arm

Between the valve tip and the rocker arm

Between the camshaft and the lifter

What kind of clearance check is typically done on an aircraft engine?

In-flight clearance check

Hot clearance check

Operating clearance check

Cold clearance check

How many degrees of intake valve lead are shown in this diagram

60 degrees

10 degrees

120 degrees

15 degrees

How many degrees of exhaust valve lead in the following diagram?

60 degrees

15 degrees

30 degrees

10 degrees

The shape of the lobe on the cam determines what?

Ignition timing & compression ratio

Valve dwell and lag

Valve lift and the length of time the valve is held open

Valve dwell and lead

What are the advantages of using a hydraulic lifter?

Increasing the force available to open the valves and valve lift

Increasing the possible valve duration and closing speed

Removing play from the valve train & cushioning the cam lobe striking the lifter

Increasing the possible valve lift and duration

What will the two cam tracks be used for on a cam ring?

One track move the piston up in the cylinder, the other moves it back down

One track controls valve opening, the other controls valve closing

One track operates the intake valve, the other the exhaust valve

One track controls the valves, the other controls ignition timing

What do radial engines use to control valve clearance

Adjusting screws and locks on the solid lifters

Hydraulic lifters

Adjusting screws and locks on the rocker arms

Adjusting screws and locks on the hydraulic lifters

What is it called when both intake and exhaust valves are open at the same time

Valve mismatch

Valve wear

Turbocharging

Valve overlap

What do rocker arm bosses do?

They control when the rocker arms operate during the otto cycle

They reduce the weight of the rocker arm so it can open & close faster

They support the shaft that the rocker arms rotate around

They are located nearby and monitor rocker arm operation to make sure it is done correctly

When is a clearance check is typically done on an aircraft engine?

At the end of the power stroke

At the beginning of the compression stroke

At the beginning of the power stroke

At the beginning of the intake or exhaust stroke depending on which valve is being checked

What does a radial engine use to follow the cam ring?

Tappet guides

Cam rollers

Cam tappets

Cam shafts

How many degrees of exhaust valve lag in the following diagram?

15 degrees

60 degrees

10 degrees

30 degrees

Where is the cam ring located on a single row radial engine?

On the side of the engine

On the top of the engine

In the back of the engine

In the front of the engine

What happens to the valve spring when a valve starts to "Float"

It loses its ability to hold the valve closed

It loses its ability to open the valve

It loses its ability to hold the valve open

It loses its ability to close the valve

Where is the cam ring located on a two row radial engine?

In the back of the engine

On the top of the engine

In the front of the engine

On the front and back of the engine

How many degrees of valve overlap are there in this diagram?

10 degrees

25 degrees

30 degrees

15 degrees

Why are two valve springs used in an aircraft piston engine?

To speed valve closing

To prevent valve float

To speed valve opening

To slow valve closing

What determines the direction of rotation for a cam ring?

The number of lobes on the cam ring and the number of cylinders on the engine

Whether the ring has gear teeth on the inside or outside

The design of the valve lifter or tapped

The location of the valves in the cylinder head assembly

Ham many cam rings will a cam shaft have?

Why do pushrods have holes drilled in the ends and through their length?

To allow oil to flow through them to go the the components in the cylinder head

To allow cooling air to get to the components in the cylinder head

To allow oil to flow through them to go the the components in the crankcase

To reduce weight so that the valves can open and close quicker

How many degrees of crankshaft rotation is the exhaust valve open?

240 degrees

180 degrees

250 degrees

255 degrees

The shape of the lobe on the cam determines what?

The spacing between the valves in the cylinder head

The distance the valve is opened & duration

The shape of the valve head and angle of the valve face

The timing of the valve opening and ignition timing

What is the purpose of a lifter?

To push the piston up for compression & exhaust strokes

To transmit the lifting force of the camshaft to a pushrod

To create additional lift over a portion of the wing during slow speed flight

To transmit the push/pull force of the camshaft to the push/pull rod

In a single row radial engine how many cam rings are there?

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