CDX Chpt 9

If an engine has a noise when it is cold, and the noise disappears when the engine is warmed up, what is a likely cause of the noise?

Piston slap

Technician A says that excessive idling of a diesel engine will cause cylinder walls to glaze and piston rings to stick. Technician B says idling an engine regularly for long periods of time causes piston rings to break. Who is correct?

Technician A

After discovering broken rings in an engine Technician A says that the rings were most likely broken due to improper installation. Technician B says the rings were broken due to excessive cylinder taper. Who is correct?

Technician B

Technician A says compression rings in a diesel are rectangular to extend engine life. Technician B says that the top compression rings have a barrel face to provide effective sealing. Who is correct?

Technician B

Technician A says that a compression test of an engine's cylinders is the best method to use to diagnose a worn-out engine. Technician B says that measuring crankcase pressure is the best method to identify a worn-out engine. Who is correct?

Technician B

Technician A says that most high horsepower diesel engines use trunk type pistons. Technician B says that most high horsepower diesel engines today use pistons with steel crowns. Who is correct?

Technician B

Which ring will cause excessive oil consumption if it is installed upside down?

The intermediate ring

If an engine has 30% loss of cross-hatch near the top of each cylinder, approximately what percentage of remaining service life does the engine have?

0%

Where is a nickel insert used in an aluminum alloy piston used by diesel engines?

Compression ring groove

While discussing the cause of a cracked piston crown with a vertical crack through the inner edge of the combustion bowl, Technician A suggests that the piston has a manufacturing defect. Technician B suggests excessive use of starting fluid cracked the piston. Who is correct?

Neither Technician A nor Technician B

Under which of the following conditions is the most engine slobber produced?

Idle conditions

Which shape is most often used for compression rings in medium- and heavy-duty diesel engines?

Keystone

Which of the following is the practice recommended to evaluate the ability of a diesel engine's piston rings to seal?

Measure crankcase pressure

Which ring face material is used on compression rings to aid upper cylinder wall lubrication?

Molybdenum

A piston's compression ring seals best during:

power stroke.