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HET2 > 201ka - Cylinder Head Service > Flashcards

201ka - Cylinder Head Service Flashcards

1
Q

What should be done before removing rocker arms and camshaft?

A

Loosen rocker arm adjusting screws

201ka pg. 4

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2
Q

Why should injectors and glow plugs be removed from the cylinder head before removing the head from the block?

A

They protrude below the bottom of the head and are easily damaged.

201ka pg. 5

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3
Q

What order should cylinder head fasteners be removed?

A

Opposite of torque sequence used for engine assembly

201ka pg. 6

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4
Q

How should a cylinder head be stored when off the engine?

A

On a set of wood blocks

201ka pg. 7

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5
Q

Where is a common place for cracks on a cylinder head?

A

Between valve seats and injector holes

201ka pg. 7

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6
Q

What should cylinder head cap screws be visually inspected for? (4)

A
  • Damaged or missing threads
  • Reduced diameter (stretched past elastic limit)
  • Corrosion or pitting
  • Stretch/Length

201ka pg. 9

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7
Q

What stiffness of wire brush should be used on cylinder head cap screws?

A

Soft bristle brush/wire wheel

201ka pg. 8

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8
Q

How should valves be stored when removed from the cylinder head?

A

Stored in order and marked to assist in diagnosis, measurement, and reassembly.

201ka pg. 11

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9
Q

What must be done to the cylinder head in preparation for pressure testing?

A

Seal all of the cylinder head coolant passages and plug injector tubes using dummy injectors

201ka pg. 12

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10
Q

What maximum pressure range is used when pressure testing a cylinder head?

A

20-40 psi

201ka pg. 13

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11
Q

When pressure testing a cylinder head, what temperature water is used and for how long is it left in the water?

A

180 - 200 F (83 - 93 C)
15 - 20 minutes

201ka pg. 13

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12
Q

What four main methods can be used to clean a cylinder head?

A
  • Petroleum solvent
  • Hot tank (not aluminum)
  • Mechanical parts washer
  • High temperature oven

201ka pg. 13

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13
Q

What would white scale indicate in the water jacket?

A

High concentration of minerals in the water that is mixed with the coolant

201ka pg. 18

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14
Q

What would green/blue deposits indicate if found in the water jacket?

A

An over-concentration of coolant

201ka pg. 18

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15
Q

What would rust or corrosion indicate in the water jacket?

A

Insufficient corrosion inhibitors in the cooling system.

201ka pg. 18

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16
Q

What should be done before measuring valve guides to ensure an accurate measurement?

A

Remove carbon buildup by using a valve guide scraper or brush.

201ka pg. 18

17
Q

What are two results of worn valve guides?

A
  • Loss of power
  • Oil consumption

201ka pg. 19

18
Q

What are two common valve face angles and what are their benefits?

A
  • 30 degrees - better airflow
  • 45 degrees - better seating force

201ka pg. 24

19
Q

What should be done with valves that have excessive runout?

A

Replaced. Do not try and straighten them.

201ka pg. 24

20
Q

After grinding down a valve face, what is the minimum margin thickness?

A

Not less than 1/2 the margin thickness of a new valve.

201ka pg. 25

21
Q

What would happen to a valve if operated with insufficient margin thickness?

A

Will run excessively hot and burn prematurely.

201ka pg. 25

22
Q

If a cylinder head is machined, where should it be stamped to indicate that it has been machined?

A

On a non-sealing surface of the cylinder head.

201ka pg. 27

23
Q

What are two methods of reconditioning integral valve guides?

A
  • Knurling
  • Repair sleeve

201ka pg. 28

24
Q

How can removable valve guides be removed from the cylinder head?

A
  • Ball peen hammer
  • Air chisel
  • Removal tool

201ka pg. 28

25
Q

What would result from a valve guide being installed too high in the cylinder head?

A

Component damage from contact between valve spring retainer and seal or top of guide.

201ka pg. 30

26
Q

How can valve seat inserts be removed?

A
  • Special chisel
  • Weld a bead around seat area
  • Insert puller tool

201ka pg. 31

27
Q

What is a valve seat insert concentricity check?

A

Checks that the valve seat is concentric with the valve guide. They must share the same centre line. Done by using a concentricity gauge and rotating it 360 degrees.

201ka pg. 34

28
Q

What tools are used to refinish valve seats?

A
  • Grinding stone - with a drill
  • Cutters - by hand

201ka pg. 35

29
Q

How is a valve seat interference angle formed?

A

By grinding the valve seat angle 0.5 to 1 degree greater than the valve face.

201ka pg. 36

30
Q

To form a valve interference angle, should the valve seat or face be ground the 0.5 to 1 degree greater?

A

Valve seat angle should always be 0.5 to 1 degree larger than valve face angle.

201ka pg. 36

31
Q

Where should the valve seat contact the valve face?

A

In the middle of the valve face.

201ka pg. 37

32
Q

What does a 15 degree stone do when grinding valve seats?

A

Lowers and narrows the contact area

201ka pg. 37

33
Q

What does a 60 degree stone result in when grinding valve seats?

A

Raises and narrows contact area

201ka pg. 37

34
Q

What valve seat cutting stone would be used to lower the contact area of the valve face?

A

A 15 degree stone

201ka pg. 37

35
Q

What valve seat stone would be used to raise the contact area?

A

A 60 degree stone

201ka pg. 37

36
Q

How do you check valve seat contact and width?

A
  • Spread a thin layer of Prussian Blue on the valve face
  • Insert valve into guide and press firmly without rotating
  • Remove valve and check where the Prussian Blue has been transferred from the valve to seat

201ka pg. 38

37
Q

How do exhaust valve seats compare to intake valve seats for size?

A

Exhaust valve seats are usually wider

Too wide - lowers seating force, carbon buildup, poor cooling

Too narrow - poor cooling, rapid wear

201ka pg. 38

38
Q

Valve head height (Protrusion) is a measure of what?

A

Distance from bottom of valve head to machined gasket surface of cylinder head.

Excessive height causes increased compression ratio
Insufficient height causes reduction in compression ratio

201ka pg. 39

HET2 (29 decks)

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