In a four-stroke cycle diesel engine, badly...

Question 1 of 270705eccefa1bacbc34ba4d476a2

In a four-stroke cycle diesel engine, badly worn intake valve guides can cause excessive __________.

Question 1 of 27070

In a four-stroke cycle diesel engine, badly worn intake valve guides can cause excessive __________.

🔍 Key Concepts

• Four-stroke diesel cycle: what happens during the intake stroke and what the intake valve/guide does • Effects of worn valve guides: how air (or combustion gases) and oil can leak past them • Relationship between valve/guide condition and engine performance indicators (oil use, temperatures, pressures)

💭 Think About

• Think about what sits around the valve stem in the cylinder head and what can leak through that space if the guide is badly worn. • Ask yourself: which of the listed items (cooling water temperature, lube oil consumption, exhaust temperature, exhaust pressure) would most directly be affected if oil or air can move more freely along the valve stem? • Consider which answer choices are mainly affected by combustion conditions inside the cylinder versus those affected by mechanical clearances in the valve train.

✅ Before You Answer

• Identify what actually passes through the intake valve and where the valve stem/guide is located relative to the combustion chamber and rocker gear oil supply. • Decide which of the four options would show a gradual, ongoing change as wear increases, rather than a sudden change from operating conditions. • Eliminate any options that are controlled primarily by cooling system design or exhaust system back pressure, rather than by valve guide clearances.