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

The precise oil clearance allows pressurized oil to form a hydrodynamic wedge between the journal and bearing, preventing metal-to-metal contact during operation.

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

Milky residue only on the filler cap is commonly caused by condensation from short-trip driving where the engine never reaches full operating temperature to evaporate moisture. If coolant were mixing with oil, the dipstick oil would also appear milky.

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

Out-of-round is determined by measuring the bore diameter at the thrust side (perpendicular to the crankshaft) and non-thrust side (parallel to the crankshaft) at the same height, then comparing the readings.

Question 4

What causes a timing belt to skip teeth?

Accepted Answer

A worn or improperly tensioned timing belt tensioner

Answer

A worn or improperly tensioned timing belt tensioner allows the belt to become slack, which can cause it to skip teeth on the sprockets, leading to valve timing errors and potential engine damage.

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

Crosshatch honing creates a pattern of fine grooves that retain oil on the cylinder walls, promoting proper piston ring seating and lubrication during the break-in period and normal operation.

Red Seal Auto Tech 310S Practice Test

Red Seal Auto Tech 310S Practice Test

310S Engine Systems and Repair 2