Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

crankshaft bearings and related components > crankshaft and bearings > Flashcards

crankshaft and bearings Flashcards

1
Q

Function of a crankshaft

A

converts reciprocating motion into rotary and rotary motion into reciprocating motion
also drives the camshaft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

cast crankshafts

A

mostly used in gas engines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Forged alloy crankshafts

A

mostly used in diesel engines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

most common crankshaft rotation

A

clockwise as viewed from the front of the engine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

do 2 stroke engines have mating pairs

A

no because all cylinders must fire in one rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

three components that contribute to engine balance

A

rotating balance weights (counter weights) vibration damper and fly wheel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how many counter balance weights will a 4 stroke engine use

A

2 driven at twice the speed of the crankshaft to cancel inertia from the pistons and con rods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

rubber element damper

A

damper hub and inertia mass bonded together with a rubber compound
rubber flexes allowing small amount of movement between hub and inertia mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

viscous damper

A

inertia mass is contained in the hub suspended in a thick silicone fluid
fluid provides resistance to mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

most common front and rear main seals used in diesel engines

A

one piece lip type seal

may ride directly on the crankshaft or on a wear sleeve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

if the flywheel must be installed in a certain position

A

can be accomplished by using dowels or offset bolt circle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

flywheel timing marks are used for

A

checking and adjusting fuel injection timing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

three types of bearings

A

full round / seamed
shell type
thrust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

two types of bearing construction

A

single metal

multi-layered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

press fit bearings

A

sleeve type pressed into the bore with an interference fit

creates crush to retain and provide good heat transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Bearing oil supply

A

pumped through a system of passage ways in the block and crankshaft
Must maintain the proper volume and pressure to maintain oil film between the bearing and the shaft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

hydrodynamic lubrication

A

rotating crankshaft acts as a pump and forces oil between the bearing and the shaft
position of the shaft in the bore depend on engine speed / load and oil pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

An unbalanced engine would have

A

Reduced mechanical efficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The balance weights in some 4 stroke engines

A

counter balance inertia forces created by the pistons and rod assemblies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

crankshafts used in diesel engines are usually hardened to increase wear characteristics of

A

the journals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Locating lugs and dowels are used for

A

positioning bearing shells in the main bores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

when removing a vibration damper

A

Never pry or hammer on them

Use appropriate puller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

front gear covers

A

usually made of stamped metal or cast and can be easily damaged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

All components removed during disassembly should be

A

stored in a safe and secure position to prevent component damage and personal injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

when removing crankshaft

A

lift as straight as possible
make sure counterweights and throws do not catch on main bearing webs
no binding between the shaft and the thrust bearing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

when removing bearing shells

A

mark upper shell for positioning and tape upper and lower together
normally replaced but should be kept for further diagnosis if needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

if more than half the bolt holes on a crankshaft are damaged it should be

A

replaced

a loosed damper or flywheel could cause major engine damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

crankshaft seal surface wear grooves les than .010”

A

can usually be polished out for reuse

if not a wear sleeve can be installed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

three main measurements done on a crankshaft

A

main and connection rod journals -out of round taper and max wear
thrust surface-located on either side of the middle or rear main bearing journal measure distance between the thrust surfaces
Straightness - use a dial indicator and rotate crankshaft in a v block

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Straightening a crankshaft

A

some can be straightened if within manufacture specs

should be recheck for cracks after

31
Q

when regrinding journals

A

reground and polished to undersize dimensions
new size stamped on front counter weight
always compare with manufacture specs to verify dimensions
all respective journals must be reground to same size

32
Q

bearings can be commonly identified by

A

stamped markings on the back of the shell

33
Q

when removing burs on the crankshaft nose

A

use a smooth cut file or a honing stone then polish with fine sandpaper

34
Q

when installing crankshaft gear

A

check for gear direction (chamfered teeth and timing marks)
Alignment of gear keyway with crankshaft keys
ensure gear is fully seated
allow gear to cool at room temp do not quench

35
Q

pilot bearing in the fly wheel

A

retained with a press fit

if loose bore can be machined and repair sleeve can be installed

36
Q

When installing a new ring gear on the fly wheel

A

make sure chamfered teeth face proper direction to engage the starter

37
Q

when removing a ring gear off the fly wheel

A

use heat and a hammer and chisel

do not heat with cutting torch as the fly wheel may get damaged

38
Q

installing a new ring gear on the fly wheel

A

ring gear has a shrink fit
gear must be heated evenly to a specific temp
after install allow gear to cool at room temp do not cool ring gear with water this can cause distortion

39
Q

when checking the fillet radius of a reground crankshaft

A

some manufactures supply a radius gauge

if the fillet radius is to small or ground incorrectly it may break in this area

40
Q

rough reground journals can cause

A

rapid bearing wear

41
Q

Minimum journal dimension

A

do not undersize less than .030” this can cause removal of hardened surface and weakens the journals

42
Q

diesel fuel in the engine oil can result from

A

internal leakage of fuel system
excessive idle time
incomplete combustion

43
Q

Diesel fuel in engine oil will cause

A

reduced viscosity causing journal to come into contact with bearing surface under load causing wiping and produces a greenish brown discoloration

44
Q

corrosion damage can be eliminated by

A

controlling operating conditions and monitoring oil change intervals

45
Q

coolant contamination effect on bearings

A

destroys bearing overlay and leads to fatigue failure of inner layer shows up as black discoloration

46
Q

improper bearing assembly

A

can cause spot loading witch will lead to fatigue failure of bearing surface
caused by misaligned tangs or foreign body between bearing and bore

47
Q

when preforming a bearing roll in

A

use a bearing removal pin in the journal oil hole

48
Q

when installing bearings during a roll in

A

do not lubricate the back side of bearing this can effect seating and heat transfer

49
Q

the accuracy of torqueing depends on

A

thread condition and cleanliness
condition of mating surface
type of thread lubricant used
accuracy of torque wrench

50
Q

after torqueing main bearing caps

A

check crankshaft for free rotation

if binding occurs work backward through torque procedure and loosen cap bolts to locate binding

51
Q

one method to adjust misaligned thrust bearing

A

loosen thrust bearing main cap bolts one turn
push crankshaft firmly to front then rear
retorque main cap bolts and re measure

52
Q

when installing gasket on front covers you should check for

A

alignment of passageways to prevent blockage

53
Q

What should be double checked before removing front or rear housing

A

bolts still holding the housing
part of the pan still attached
are there specific pry points

54
Q

Why is the annular grove in a bearing shell usually placed in the block side of the main bearing bore

A

to give the loaded side more surface area

to ensure oil can flow from the hole in the block to the hole In the crank

55
Q

when a journal is machined what type of bearing size would be required

A

Undersized

56
Q

if one crankshaft main journal needed to be repaired

A

machine all main journals and install undersized bearing

57
Q

what type of seal is most often used on a crankshaft

A

a one piece lip type

58
Q

what is the best method to install s main seal

A

press it in from the front with an installation tool

59
Q

why would there be numbered markings on a flywheel

A

used as a crankshaft position reference

60
Q

what is a friction type bearing

A

has no moving parts uses a film of oil

61
Q

where would bushings usually be

A

to support in block camshaft

62
Q

what is the purpose of a thrust bearing

A

controls axial movement

63
Q

how are the main journals and connecting rod journals connected

A

by the webs

64
Q

when is a crankshaft ground and polished

A

after induction hardening

65
Q

how many main bearings support each connecting rod assembly in an inline engine

A

two mains for every one rod assembly

66
Q

what speed and what direction do 4 stroke counter balance shafts turn at

A

twice crank speed in opposite directions

67
Q

what type of construction is most common for a shell type bearing

A

two piece multi layer construction

68
Q

if a bearing fails due to heavy loading what type of damage would be seen

A

spalling

69
Q

what is the purpose of lateral grooves in a bearing

A

to supply oil to the thrust face of the bearing

70
Q

what areas of the crankshaft are considered critical loading areas

A

oil holes webs and fillets

71
Q

what would cause a crankshaft to break at the main journals

A

misaligned main bearing bores

72
Q

what would cause a crankshaft to brake at the rod journals

A

excessive torsional loads

73
Q

what would cause wiping of a bearing surface

A

loss of oil film

74
Q

when preforming a bearing roll in what should be done before removing bearing caps

A

loosen drive belts

crankshaft bearings and related components (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions