Cylinder Head and Valve Train Module

Question 1

What is the purposes of a camshaft?(2)

Answer 1

-Changes rotary motion to reciprocating motion
-Controls opening and closing of intake and exhaust valves

Question 2

2 types of cam arrangements

Answer 2

Cam in block
Over head cam

Question 3

True or False;
The camshaft gear is smaller than the crankshaft gear on a four stroke engine.

Answer 3

False - because it rotates slower

Question 4

The 4 components in a valve train.

Answer 4

Camshaft
Lifter
Push Rod
Rocker Arm

Question 5

What speed does the camshaft rotate in relation to the crankshaft on a 4 stroke engine?

Answer 5

Camshaft rotates at 1/2 the speed of the crankshaft.

Question 6

3 types of cam followers;

Answer 6

Solid
Roller
Hydraulic

Question 7

What keeps the camshaft timed with the crankshaft?

Answer 7

Gears, Chain, or Timing Belt

Question 8

True or False;
Pushrods may have hollow tubes with oil galleries so oil can be sent to the cylinder head.

Answer 8

True

Question 9

Which valve train component makes up the mechanical link between the pushrod and valve?

Answer 9

Rocker Arm

Question 10

What is the purpose of the cylinder head ports?

Answer 10

The cylinder head ports direct flow in and out of the cylinders

Question 11

3 main functions of the cylinder head.

Answer 11

-Retains gasket seal between head + block

-Contains combustion chamber, valves, oil and coolant galleries

-Houses manifolds and injectors, air start and gas admission valves

Question 12

2 basic functions of valves are;

Answer 12

-Seals cylinder during compression and power events

-Permits air/fuel mix on intake, removes combustion gases on exhaust

Question 13

Why is an exhaust valve usually made of higher quality materials than an intake valve?

Answer 13

-Operates at higher temperatures

-Subject to corrosive gases flowing through

Question 14

On a solid stem valve, the majority of the cooling takes place at the;

Answer 14

Valve face and Valve Seat

Question 15

When compared to an integral valve seat, valve seat inserts provide a replaceable wear surface with improved….

Answer 15

Wear characteristics

Question 16

Valve seals control valve guide and stem lubrication to prevent;

Answer 16

Oil consumption

Question 17

Before removing the cylinder head from a locked out and purged engine, you must do what task first?

Answer 17

Drain the oil and coolant

Question 18

After replacing valves and valve seat inserts, you should always check;

Answer 18

Valve face and valve seat contact

Question 19

Which valve type usually requires more clearance and why?

Answer 19

Exhaust valve
-high exhaust gas temperatures flowing through the valve and valve seat.

Question 20

True or False;
When adjusting valve lash using the firing order of an engine, the piston should be positioned at TDC and in the compression stroke with both valves closed for that cylinder.

Answer 20

True

Question 21

What type of lever is a rocker arm?

Answer 21

Class 1 lever

Question 22

What do valve seals do?

Answer 22

Control lubrication of the valve guide and stem

-bad valve seals, blue smoke on initial acceleration.