engine repair 12/8/2022

Front

Overhead cam engines timing chains may use ______tensioners

Back

All of the above

Answer explanation

Overhead cam engines can utilize various types of tensioners for timing chains, including mechanical, spring, and hydraulic. Therefore, the correct answer is 'All of the above' as all these types are applicable.

Front

Timing belt service intervals are critical on many engines because

Back

valve damage may occur if the belt fails

Answer explanation

Timing belt service intervals are critical because if the belt fails, it can lead to valve damage, which is costly to repair. While timing affects idle quality, the primary concern is the potential for severe engine damage.

Front

An engine emits blue smoke for a few seconds when starting cold; the MOST likely cause is

Back

Worn valve seals

Answer explanation

Blue smoke on cold start typically indicates oil burning. Worn valve seals allow oil to enter the combustion chamber, especially when the engine is cold, leading to blue smoke. This makes 'Worn valve seals' the most likely cause.

Front

What is the primary advantage of round-toothed timing belts when compared to square-toothed timing belts?

Back

Quieter operation

Answer explanation

Round-toothed timing belts operate more quietly than square-toothed belts due to their design, which reduces vibration and noise during operation. This makes them preferable in applications where noise reduction is important.

Front

When replacing a cylinder head gasket, which type of head bolts should always be replaced?

Back

torque to yield

Answer explanation

When replacing a cylinder head gasket, it's crucial to replace torque to yield head bolts. These bolts are designed to stretch and cannot be reused safely, as they may not provide the necessary clamping force if reused.

Front

A plastigage is used to determine

Back

main and rod bearing clearance

Answer explanation

A plastigage is specifically designed to measure the clearance between main and rod bearings. It provides an accurate reading of the gap, which is crucial for engine performance, making this the correct choice.

Front

What is a micrometer used for?

Back

Precision measurements

Answer explanation

A micrometer is a precision instrument used to measure small distances or thicknesses with high accuracy, making 'Precision measurements' the correct choice. The other options do not relate to the primary function of a micrometer.

Front

Which of the following is not part of a connecting rod: I-beam, cap, bushing?

Back

Lobe

Answer explanation

The lobe is not a component of a connecting rod. A connecting rod typically consists of an I-beam structure, a cap, and a bushing, which are essential for its function in an engine.

Front

If an engine noise can be reduced or eliminated by shorting out an individual cylinder, the most likely cause is

Back

Worn connecting rod bearing

Answer explanation

Shorting out a cylinder reduces noise caused by a worn connecting rod bearing, which can create knocking sounds. The other options are less likely to directly affect engine noise in this manner.

Front

Excessive tread wear on both tread shoulders is probably caused by

Back

under inflation

Answer explanation

Excessive tread wear on both tread shoulders is typically caused by under inflation. When tires are under-inflated, the outer edges of the tread wear more quickly due to increased contact with the road.