Deck 12: Four-Stroke Engine Top-End Inspection

Question 1

Piston ring gaps should be ____degrees apart on the piston during installation.

A)90
B)180
C)60
D)120

Answer 1

D

Question 2

Describe how you lap valve seats.

Answer 2

To begin lapping, apply a thin coating of lapping compound to the face of the valve. Insert the valve into the guide and rotate the valve back and forth with a lapping tool. Prussian Blue can be used to check the contact between the valve and its seat.

Question 3

The most common cause of detonation is a spark plug with the wrong heat range.

Answer 3

False

Question 4

The ___ ring is designed to remove most of the oil from the cylinder wall.

A)compression
B)oil control
C)oil scraper
D)O

Question 5

Pre-ignition occurs when the fuel and air mixture ignites before the spark plug fires.

Question 6

Explain how a technician diagnoses engine problems.

Question 7

A compression check is the most comprehensive diagnostic test you can make to an engine.

Question 8

The ______ring is designed to seal most of the combustion pressure on top of the piston.

A)compression
B)oil control
C)oil scraper
D)O

Question 9

How do you check a valve guide and what tools will you need?

Question 10

Use a ______ to remove the valves from the head for inspection.

A)dead blow hammer
B)case splitter
C)spring compressor
D)vernier caliper

Question 11

Some four-stoke engines require you to split the cases to remove the top end.

Question 12

Air leaking from the intake manifold means the ___________is (are)leaking.

A)exhaust valves
B)intake valves
C)piston rings
D)head gasket

Question 13

Describe the procedure for inspecting a four-stroke engine's valves.

Question 14

How do replace valve guides and what precautions should you observe?

Question 15

The middle ring on a piston scrapes the excess oil from the cylinder wall when the piston is moving downward.