310S Engine Systems and Repair 2

Question 1

What is the purpose of the oil clearance between a crankshaft journal and its bearing?

Accepted Answer

To create a hydrodynamic oil wedge for lubrication

Answer

To allow thermal expansion of the crankshaft

Answer

To reduce the weight of the rotating assembly

Answer

To allow for manufacturing tolerances only

Question 2

A technician finds milky residue on the oil filler cap. What is the most likely cause?

Accepted Answer

Normal condensation from short-trip driving

Answer

Overfilled engine oil

Answer

Coolant mixing with engine oil

Answer

Use of incorrect oil viscosity

Question 3

What is the correct procedure for measuring cylinder bore out-of-round?

Accepted Answer

Use a telescoping gauge or bore gauge at thrust and non-thrust sides at the same height

Answer

Measure at the top and bottom of the bore with a tape measure

Answer

Measure the piston diameter and subtract from the nominal bore size

Answer

Use a feeler gauge between the piston and cylinder wall

Question 4

What causes a timing belt to skip teeth?

Accepted Answer

A worn or improperly tensioned timing belt tensioner

Answer

Excessive oil contamination on the belt

Answer

Using premium fuel instead of regular

Answer

A faulty mass airflow sensor

Question 5

What is the purpose of crosshatching the cylinder walls during an engine rebuild?

Accepted Answer

To provide oil retention for proper ring seating

Answer

To increase the bore diameter to specification

Answer

To remove rust and corrosion from the cylinder walls

Answer

To create a smooth surface for reduced friction

Question 6

An engine with variable valve timing (VVT) has a rattling noise at startup. What is the most likely cause?

Accepted Answer

A failed VVT phaser or actuator with internal wear

Answer

Worn main bearings

Answer

Loose heat shields on the exhaust manifold

Answer

Incorrect spark plug gap