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.