Technician A says engines have replaceable piston rings to minimize gas leakage past the piston. Technician B says an intermediate ring has compression-sealing functions, but no oil control functions. Who is correct?

• Tech A

• Tech B

• Both

• Neither

What component is used to prevent a block camshaft from wearing on the block surface?

• Thrust washer

• Prevent washer

• Rubber washer

• None of these is correct

Technician A says a gear train or valve timing mechanism is used to coordinate the movement of the crankshaft with the camshaft and the valves. Technician B says the gear train does not operate power take-off (PTO) pumps. Who is correct?

• Tech A

• Tech B

• Both Tech A and Tech B

• Neither Tech A or Tech B

Where should desired maximum cylinder pressure occur?

• 10-15 degrees BTDC

• 10-15 degrees ATDC

• 10-15 degrees BBDC

• 10-15 degrees ABDC

An advantage of the Navistar's Eco Motors EM100 engine is that it has __________ fewer parts than an equivalent four-stroke cycle engine.

• 20%

• 30%

• 40%

• 50%

On- and off-highway vehicle emissions from the 1970s to present have been reduced by __________.

• 27%

• 13%

• 29%

• 39%

Technician A says hydrocarbon emissions are formed because of fuel that have been burned completely. Technician B says fuels are classified as hydrocarbons because they are made of mostly hydrogen and carbon atoms. Who is correct?

• Tech A

• Tech B

• Both Tech A and Tech B

• Neither Tech A or Tech B

Which of the following statements about carbon monoxide is correct?

Select one:

• Carbon monoxide is created because of incomplete combustion of carbon-based fuels.

• Higher compression pressures and excess air used in diesel combustion limit carbon monoxide formation in diesels

• Both A and B

• Neither A nor B

Technician A says blow-by is the leakage of air past the piston rings into the crankcase. Technician B says that in any engine, blow-by occurs mostly during the compression stroke. Who is correct?

• Technician A

• Technician B

• Both Technician A and Technician B

• Neither Technician A nor Technician B

What is another name for a core plug?

• Retainer Plug

• Frost Plug

• Sand Plug

• Block Plug