Question 1

____________________ is a very rapid movement of gases that causes the air and fuel to mix better and improve combustion.

Accepted Answer

The answer of ____________________ is a very rapid movement of...

Question 2

Resurfacing the cylinder head can affect _____.

Accepted Answer

Resurfacing the cylinder head can indeed affect the compression ratio by reducing the volume of the combustion chamber, valve timing by slightly altering the position of the camshaft relative to the crankshaft, and piston to valve clearance by bringing the valves closer to the pistons, potentially reducing clearance.

Question 3

A pentroof combustion chamber is normally found on a(n)_____type cylinder head.

Accepted Answer

Pentroof combustion chambers are typically found on engines with four valves per cylinder, as this design allows for better airflow and more efficient combustion by accommodating two intake and two exhaust valves per cylinder.

Question 4

Technician A says if valve stem height exceeds specifications, it can be adjusted by grinding the valve tip. Technician B says the valve stem height can be adjusted with shims. Who is correct?

Accepted Answer

The answer of Technician A says if valve stem height...

Question 5

Technician A says the end of the valve spring that is wound the tightest should face toward the spring retainer. Technician B says the O-ring seal should be installed in the lowest of the keeper grooves on the valve stem.

Accepted Answer

The answer of Technician A says the end of the...

Question 6

_____type valve stem seals move up and down with the valve stems to deflect oil away from the guides.

Accepted Answer

Umbrella type valve stem seals move with the valve stems and deflect oil away from the valve guides.

Question 7

Installed spring height [the distance between the spring seat and the bottom of the retainer] can be measured with a spring height gauge or ____________________.

Accepted Answer

The answer of Installed spring height [the distance between the...

Question 8

Technician A says multivalve engines can have two valves per cylinder. Technician B says multivalve engines must have five valves per cylinder. Who is correct?

Accepted Answer

The answer of Technician A says multivalve engines can have...

Question 9

Hemispherical combustion chambers are being discussed. Technician A says the flame path from the spark plug to the piston head is long, which provides efficient burning. Technician B says the cross-flow arrangement of the inlet and exhaust valves allows for a free flow of gases in and out of the chamber. Who is correct?

Accepted Answer

Technician B is correct because the cross-flow arrangement in hemispherical combustion chambers allows for efficient gas exchange. Technician A is incorrect because a shorter flame path is generally more efficient for combustion.

Question 10

Technician A says VVT (variable valve timing)engines use a cam phaser that advances or retards the camshaft as the engine is running. Technician B says VVT engines use a third cam lobe with increased lift and duration, operating a third rocker arm that is coupled to the two primary rocker arms by a hydraulically controlled pin, while the engine is running. Who is correct?

Accepted Answer

The answer of Technician A says VVT (variable valve timing)engines...

Question 11

Technician A checks for bent pushrods by rolling them on a flat surface. Technician B checks for bent pushrods using a dial indicator and V-blocks. Who is correct?

Accepted Answer

Both methods are valid for checking for bent pushrods. Rolling them on a flat surface can reveal bends as the pushrod will wobble if it's not straight. Using a dial indicator and V-blocks is a more precise method to measure for bends.

Question 12

Technician A says multivalve engines have a more complete combustion than conventional engine designs. Technician B says the benefits of multivalve engines may be offset by a more complicated camshaft arrangement. Who is correct ?

Accepted Answer

Multivalve engines do allow for more complete combustion due to increased air flow and better fuel distribution, which is what Technician A suggests. Technician B is also correct in stating that the benefits of multivalve engines can be offset by the complexity of their camshaft arrangements, which can make them more complicated and potentially more expensive to manufacture and maintain.

Question 13

Technician A says heat is transferred from an exhaust valve to the cylinder head through the valve seat. Technician B says some exhaust valves have a hollow stem filled with silicone to transfer heat to the valve guide. Who is correct?

Accepted Answer

The answer of Technician A says heat is transferred from...

Question 14

Valve guides are _____.

Accepted Answer

Valve guides can be integral (machined directly into the cylinder head), pressed in as cast iron inserts, or pressed in as bronze inserts, depending on the engine design and manufacturer's preference.

Question 15

Technician A resurfaces valve seats using a grinding stone. Technician B resurfaces valve seats using a cutting blade. Who is correct?

Accepted Answer

Both techniques are valid for resurfacing valve seats. Technician A uses a grinding stone, which is a common method, and Technician B uses a cutting blade, another accepted method.

Question 16

The type of valve used in automotive engines is called a ____________________.

Accepted Answer

The answer of The type of valve used in automotive...

Question 17

____________________ support the valve in the head and prevent the valve from moving in any direction other than up and down.

Accepted Answer

The answer of ____________________ support the valve in the head...

Question 18

Cylinder head warpage can be measured with _____.

Accepted Answer

A straightedge and feeler gauge are commonly used to measure cylinder head warpage by checking for gaps between the straightedge and the cylinder head surface.

Question 19

Prussian blue or machinist dye is used to ______.

Accepted Answer

Prussian blue or machinist dye is commonly used to check the width and position of the valve-to-seat contact pattern in engine maintenance and repair. It helps in ensuring that the valve and seat are making proper contact for efficient engine operation.

Question 20

After resurfacing a valve seat at 45 degrees, the seat is too wide and the contact pattern extends all the way up to the valve margin. What should be done to bring the seat width into specifications?

Accepted Answer

A 30-degree topping cut will narrow the seat width and bring it into specifications.

Quiz 12: Upper-End Theory and Service