Deck 12: Piston, Rings, and Connecting Rod

Question 1

Technician A says a wrist pin is also known as a piston pin. Technician B says a piston pin is chrome-plated, high grade carbon steel. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Answer 1

C

Question 2

Most of today's automotive pistons are slipper skirt pistons.

Answer 2

False

Question 3

Technician A says the oil rings account for 60% of total drag on the cylinder wall. Technician B says the compression rings account for 40% of total drag on the cylinder wall. Who is right?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Answer 3

C

Question 4

Technician A says forged pistons are available for heavy-duty or high-performance use. Technician B says that a cast piston is more efficient at dissipating heat.

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 5

Automobile piston pins are either pressed fit or full floating.

Question 6

The big end of a rod can be up to 0.004" out of round before it needs resizing.

Question 7

Technician A says powder forged rods are not cut; they are fractured (broken). Technician B says some rods have a spit hole to lubricate the cylinder walls at lower rpms. Who is right?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 8

All of the below are coatings used to reduce friction on pistons, EXCEPT _____.

A) Teflon
B) silicone
C) graphite
D) moly

Question 9

Name four common piston head shapes.

Question 10

Technician A says reverse twist rings do better controlling blowby. Technician B says standard torsional twist rings do better controlling oil. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 11

Piston rings are made from all these materials, EXCEPT _____.

A) ductile iron
B) aluminum wire
C) steel wire
D) cast iron

Question 12

Hypereutectic is the description of a popular cast aluminum alloy referring to the percentage of silicon in the aluminum in a piston.

Question 13

Technician A says that a good piston can be ruined by cleaning the grooves on a wire wheel. Technician B says an old, broken piston ring works well to clean the ring grooves. Who is right?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 14

Ring gaps on an opposed engine design should be faced down.

Question 15

Piston diagnosis is being discussed. Technician A says scuffing on one skirt only can be caused by excessive low rpm idling. Technician B says scuffing of the piston skirt can be caused by abnormal combustion or cooling system problems. Who is right?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technicians

Question 16

Technician A says that the top compression ring groove wears more than the other ring grooves. Technician B says that full floating, piston pin lock rings should be installed with their openings facing up. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 17

Technician A says a piston usually has a direction identifying notch that faces the rear of the engine. Technician B says a piston exhibits more wear on its major thrust side. Who is right?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician