Deck 18: Engine Upper End

Question 1

13)The term that is MOST-Likely to be used to describe the number of degrees of crankshaft rotation that occurs while both the intake and exhaust valves are open at the same time is:

A) valve overlap
B) backlash
C) zero-lap
D) end thrust

Answer 1

A

Question 2

7)While discussing intake seals, Technician A says that a faulty intake valve seal will allow oil to be pulled into the cylinder from the low pressure created during the intake stroke. Technician B says that a leaking intake seal can cause carbon buildup on the valve stem, which interferes with engine breathing. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Answer 2

C

Question 3

18)The more air and fuel drawn into the cylinder in the correct proportion (not too rich or lean), the more power an engine can produce. This is called ____________________.

Answer 3

volumetric efficiency

Question 4

16)____________________ seats are found in original equipment aluminum heads and in iron heads that have been repaired by a machine shop.

Question 5

5)Older shaft-mounted rocker arms are usually made of cast iron.

Question 6

14)While having a discussion about value overlap, Technician A says that a cam grind that will benefit performance at high rpm will hurt performance at low rpm. Technician B says if it benefits performance at high rpm, it will aid performance at low rpm. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 7

3)The intake valve is usually 35%-40% smaller than the exhaust valve.

Question 8

20)Camshafts on many OHC engines are driven by a cogged belt drive, called a(n) ____________________.

Question 9

17)The number of cam ____________________ depends on the number of valves that need to be opened.

Question 10

8)Valve guide seals are LEAST-Likely to come in which of the following types?

A) Umbrella
B) Positive
C) O-ring
D) A-ring

Question 11

15)All of the following statements are true EXCEPT:

A) cams with mechanical valve lash adjustment have a clearance ramp at the beginning and end of each lobe.
B) a high performance camshaft will have high engine vacuum at idle.
C) advanced cam timing improves low and mid-range torque.
D) retarded cam timing improves high rpm power.

Question 12

12)All of the following statements are true EXCEPT:

A) the intake valve must open before TDC, when the piston starts down on the intake stroke.
B) the intake valve stays open long after BDC into the compression stroke.
C) the exhaust valve remains open past TDC.
D) non-freewheeling engines often have a decal on the valve cover stating that the belt must be changed at least every 10,000 miles.

Question 13

11)If the timing chain or belt skips or breaks, pistons and valves collide, often resulting in major engine damage. This engine is MOST-Likely to be a(n):

A) freewheeling engine
B) noninterference engine
C) interference engine
D) production engine

Question 14

9)The ____ determines how well an engine breathes at a particular engine rpm.

A) cam follower
B) camshaft
C) lifter
D) timing belt

Question 15

10)On cam-in-block (pushrod) engines, the part that rides on the cam lobe is called a(n) ____.

A) lifter
B) timing belt
C) valve
D) end thrust

Question 16

4)A burned valve causes a misfire that is evident at idle but not at higher engine speeds.

Question 17

2)Integral valve seats on cast iron heads manufactured mostly after 1970 were induction hardened to reduce valve seat wear.

Question 18

1)Replaceable insert guides are only used in cast iron cylinder heads.

Question 19

6)Which of the following is LEAST-Likely a loose part of a bare head?

A) The cylinder bore
B) The intake and exhaust valves
C) The keepers and retainers
D) The rocker arms

Question 20

19)On overhead cam engines, the part that rides on the cam lobe is called a(n) ____________________.

Question 21

21)What is an advantage of integral seats?

Question 22

25)Compared to chain drives, what are the advantages of belt drives?

Question 23

24)What is the difference between shaft-mounted rocker arms and stud-mounted rocker arms?

Question 24

23)What is coil bind?

Question 25

22)How would you test for a burned exhaust valve?