Engines

Question 1

What is torsional vibration

Answer 1

Rhythmic change in crankshaft speed

Question 2

Wjat is primary balance

Answer 2

When a counterweight on the crankshaft offsets movement of piston and connecting rod

Question 3

What is secondary balance

Answer 3

Movement of one piston off sets another, uses a second piston to offset another

Question 4

What is the main purpose of a crankshaft

Answer 4

Convert linear motion of connecting rods into rotational energy

Question 5

What is an elastomer dampener

Answer 5

Consists of an inner hub outer hub and rubber ring

Question 6

What is a viscous dampener

Answer 6

Has fluid inside, silicone fluid acts like a spring

Question 7

What isba combo dampener

Answer 7

A combo of viscous and elastomer dampener

Question 8

What is a rotating pendulum vibrating absorber

Answer 8

Series of rollers that act between a drive hub and outer hub that allow relative movement to offset vibrations

Question 9

What is a balance shaft dampeners

Answer 9

Run at 2x engine speed

Question 10

What is a deep skirt block

Answer 10

Has a skirt below the crankshaft

Question 11

What is a ladder frame block

Answer 11

All caps are connected as one, looks like a ladder

Question 12

What is a tunnel bore block

Answer 12

Strongest block, small bore diesel, crankshaft tunnels into back of block when installed

Question 13

What are the 4 types of blocks

Answer 13

1. Deep skirt
   2.ladder frame
   3.tunnel bore
   4.crossbolted

Question 14

What Is a parent bore block

Answer 14

A block with no removable sleeves or liners

Question 15

Cylinder sleeve blocks

Answer 15

Have replaceable liners that make your cylinder walls

Question 16

What are the 3 types of liners

Answer 16

Dry-liner not exposed to coolant
Midstop-seat flange halfway down”mid”
Wet-outside of center exposed to coolant for heat transfer

Question 17

What does the cross hatch pattern achieve

Answer 17

Helps retain oil, helps break in rings, as cross hatch wears oil consumption increases so does blowby. Power decreases

Question 18

What are the main parts of a piston

Answer 18

Crown
Ring belt
Skirt

Question 19

What is a slipper skirt piston design

Answer 19

A piston design that has a portion of the skirt removed on the non thrust sides of the piston to provide clearance for crankshaft counterweights

Question 20

What is a monotherm piston

Answer 20

One piece piston design made entirely of alloyed stee, has a compact height and large reduction of material between skirt and crown

Question 21

What is an articulating piston

Answer 21

Two piece piston design that uses a separate aluminum skirt connected to an alloy steel crown through a piston pin

Question 22

What is a cam ground piston

Answer 22

An oval shaped piston that once warmed up rounds

Question 23

What is a trunk piston

Answer 23

Piston design that is dimensionally longer than it is wide with a full piston skirt

Question 24

Ehat are the 3 types of piston rings, what do they do

Answer 24

1.compression- for compression. Keystone shape notch up
2. Intermediate- for compression and oil taper face notch down
3.oil control- coiled expander ring, scraper rails

Question 25

Crankshaft spacing is set to equal 720° of rotation so if you have 6 cylinders what is the degree of spacing per rod journal? What If you have 4 cylinders? What if you have 8 cylinders?

Answer 25

720°÷6=120° of spacing between rod journals
720°÷4=180° of spacing between rod journals
720°÷8=90° of spacing between rod journals

The amount of spacing between rod journals always adds up to 720° of rotation

So 720°÷ # of cyl= spacing between rod journal

Question 26

What is slobber, what causes slobber

Answer 26

A mix of carbon, soot and condensation
Caused by excessive idle and low temp operation

Question 27

What type of bearing is used on crankshaft main bearing sets

Answer 27

Friction bearing

Question 28

If bearing clearance is too little what’s the cause

Answer 28

High oil pressure

Question 29

If bearing clearance is too much whats the cause

Answer 29

Low oil pressure

Question 30

What controls maximum oil pressure in an engine?

Answer 30

Relief valve

Question 31

What would not enough liner protrusion cause?

Answer 31

It would cause the liners to wear excessively

Question 32

What would cause liners to be damaged upon installation?

Answer 32

Too much liner protrusion

Question 33

What is a cylinder contribution test

Answer 33

A test that determines a cylinders contribution to total engine power

Question 34

When doing a compression test and you have low pressure on the dry test and good pressure on the wet test what does this mean

Answer 34

Bad rings

Question 35

What are the three ways pistons are cooled?

Answer 35

Piston rings
Valve overlap
Cooling nozzles

Question 36

What is the allowable wear for cylinder cross hatch

Answer 36

20%

Question 37

If you have 10% of cylinder cross hatch left how much service life is left?

Answer 37

50% service life at 10% wear

Question 38

Would you use and undersized or oversized bearing for a crankshaft that is worn or has been ground to undersize?

Answer 38

Undersized bearing for worn crankshaft or ground

Question 39

Would you use and undersized or oversized bearing for a block that has been damaged and had the bearing bore re-bored?

Answer 39

You would use an oversized bearing for a bearing bore that has been re-bored

Question 40

If you have too little liner protrusion what can you do?

Answer 40

You can add a shim underneath the liner flange

Question 41

If liner protrusion is too high what can you do?

Answer 41

Swap it out for a liner with less protrusion. Very rarely is liners machined to lower liner protrusion

Question 42

What must you do before you measure liner protrusion?

Answer 42

Clamp it in place