190201d Piston, Piston Ring and Connecting Rod Fundamentals

Question 1

List 4 main components of a piston and con rod assy

Answer 1

connecting rod
piston
piston pin
piston rings

Question 2

cylinder temperature can reach

Answer 2

3500F (1926.7C)

Question 3

cylinder pressures can reach

Answer 3

2000 psi (13789.5 kPa)

Question 4

what type of piston skirts will most diesel engine use

Answer 4

full skirt or semi-slipper skirt

Question 5

what are the two types of piston pins used

Answer 5

full floating or semi-floating

Question 6

what are the methods used to cool pistons

Answer 6

splash, spray, circulation and shaker

Question 7

functions of the piston rings

Answer 7

cool pistons, control lubrication and a gas tight seal

Question 8

how would an interference fit full floating piston pin be removed

Answer 8

heat the piston boiling water or an oven

Question 9

what are the standard piston oversizes

Answer 9

0. 010’, 0.020” & 0.030”

0. 25mm, 0.50mm & 0.75mm

Question 10

aluminum pistons should not be cleaned using

Answer 10

hot tank

Question 11

advantage of cast iron pistons

Answer 11

with stand more heat

Question 12

advantages of aluminum pistons

Answer 12

lighter than cast iron, less engine vibration,, 3 times the conductivity of cast iron & bearing surface for the piston pin

Question 13

advantages of hypereutectic aluminum pistons

Answer 13

increased strength, increase durability, lighter & reduced thermal expansion rate

Question 14

disadvantages of aluminum pistons

Answer 14

strength decreases faster than cast iron when heated,

aluminum has twice the expansion rate & great wear rate

Question 15

two common piston designs

Answer 15

trunk and two piece

Question 16

the area of the piston wear the ring land and grooves are located is also known as the:

Answer 16

ring belt

Question 17

the ring belt area on a tapered skirt piston is __________ diameter than the skirt

Answer 17

smaller than the skirt

Question 18

what retains full floating piston pin in the piston

Answer 18

snap-rings

Question 19

advantages of a two piece piston

Answer 19

crown can be made cast iron or steel, skirt out of aluminum
crown absorbs the forces of combustion not the skirt
piston crown motion is reduced
bending stress on the piston pin is reduced

Question 20

describe a trunk type piston

Answer 20

one piece full skirt design

Question 21

advantage of keystone rings

Answer 21

stronger lands , more resistant to carbon build up & less sticking

Question 22

how are keystone ring checked for serviceability

Answer 22

ring groove wear gauge

Question 23

purpose of the connecting rod

Answer 23

forms a link between the piston and crankshaft

Question 24

four methods maintaining connecting rod to cap alignment

Answer 24

shoulder bolts, dowels, tongue and groove joint and serrated joint (fractured rod)

Question 25

reason for the ring groove inserts on aluminum pistons

Answer 25

reinforce and reduce the wear on the compression ring grooves

Question 26

purpose of the ring expander on the oil control ring

Answer 26

provide tension on the ring for good oil control

Question 27

what is the purpose of the oil ring expander?

Answer 27

provide ring tension for the oil control ring

Question 28

what is the purpose for having specific amount of ring end clearance?

Answer 28

heat expansion

Question 29

what is used to retain a “full floating” piston pin?

Answer 29

snap rings (gap towards the bottom of the piston)

Question 30

where the rings ride is referred to as?

Answer 30

ring belt

Question 31

most heavy duty engines use a ______ or _____ piston skit?

Answer 31

full skirt or semi-slipper type