Chapter 4

Question 1

Give a brief explanation of why cylinder ridge must be removed before pushing the piston and connecting rod from the cylinder.

Answer 1

The piston rings will catch the ridge, making the piston difficult to remove and possibly damaging the piston and the rings.

Question 2

List two safety precautions when using a rotary wire brush to remove a carbon ridge from a cylinder.

Answer 2

Wear eye protection.

Make sure that the wire brush is suitable for the speed of the tool turning it.

Question 3

In preparation for piston and connecting rod removal, the piston to be removed should be positioned at:

Answer 3

BDC

Question 4

Explain why it is necessary to remove piston cooling from some engines when removing and installing piston and connecting rod assemblies.

Answer 4

To prevent damage to the piston cooling nozzle.

Question 5

When removing and installing piston rings, a ring expander should be used to:

Answer 5

To prevent piston and ring damage.

Question 6

List the parts of the piston that should not be bead blasted.

Answer 6

Ring Grooves
Skirt
Piston pin bores

Question 7

When scraping carbon from the ring grooves of a piston care must be taken to ensure that:

Answer 7

Metal is not removed from the ring groove area.

Question 8

What tool should be used to measure wear in a keystone piston ring groove?

Answer 8

Ring groove wear gauge

Question 9

Pistons should be visually inspected for signs of:

Answer 9

Cracks in the crown, skirt and piston pin bores.
Scuffing and scoring on the skirt, ring lands and crown.
Signs of wear or erosion in the ring grooves.
Looseness or debonding of inserts.

Question 10

The skirt of a piston should be measured at a point midway down the skirt and ______ to the piston pin bores.

Answer 10

90 Degrees

Question 11

List three problems that will occur with worn piston ring grooves.

Answer 11

Blowby
Oil consumption
Broken piston rings

Question 12

Calculate the piston clearances with the following measurements.
Piston skirt diameter: 4.9985”
Cylinder bore diameter: 5.0017”

Answer 12

0.0032”

Question 13

What would be the result of a piston installed with insufficient clearance between the skirt and the cylinder wall?

Answer 13

scuffing/scoring and eventual piston siezure

Question 14

Piston pins should be measured to determine:

Answer 14

Minimum outside dimension and out of round.

Question 15

Calculate the piston pin clearance using the following measurements:
Piston pin diameter: 2.4997”
Piston pin bore diameter: 2.5012”

Answer 15

0.0015”

Question 16

List the method that can be used to check a connecting rod for cracks.

Answer 16

Dye check.
Magnetic particle.
Magnaflux.

Question 17

List the three measurements that must be made to determine the condition of the large end bore of a connecting rod.

Answer 17

Bore size.
Out of round.
Taper.

Question 18

A bent connecting rod will cause:

Answer 18

Uneven wear and loading on the connecting rod journal and bearing, piston crown and skirt, piston pin and bores.
Reduced compression ratio.

Question 19

Unless otherwise specified by the manufacturer, when installing a full floating piston pin, you should install the gap in the snap rings:

Answer 19

Towards the bottom of the piston skirt.

Question 20

A full floating piston pin that has a slight interference fit at room temperature should be removed or installed by:

Answer 20

Heating the piston in boiling water or an oven.

Question 21

Briefly explain how to position a piston ring in a cylinder bore to measure end gap.

Answer 21

Push each piston ring squarely into an unworn area of the cylinder bore.

Question 22

What would be the result of piston rings being installed with insufficient piston ring end gap?

Answer 22

Piston ring would seize up in the bore.

Question 23

Briefly explain why piston ring end gaps must be staggered before the piston is installed in the cylinder.

Answer 23

To limit the amount of cylinder pressure, combustion gas and oil leakage that can pass by the rings during engine operation.

Question 24

When installing connecting rod bearing shells in the rod and cap it is important to check the:

Answer 24

Alignment of locating tangs and oil holes.

Question 25

During installation, piston and connecting rod assemblies must be correctly positioned in relation to the cylinder block to:

Answer 25

prevent contact with internal engine components.

Question 26

List three methods for torquing connecting rod fasteners.

Answer 26

torque wrench.
torque and turn.
bolt stretch gauge.

Question 27

Explain why bearing clearance is necessary.

Answer 27

Bearing clearance is necessary for expansion and lubrication of the connecting rod journal and bearing.

Question 28

What check should be performed after torquing the fasteners of each connecting rod?

Answer 28

Check the crankshaft for free rotation.