MDE Unit 3 Chain and Belt driven camshaft timing, tappets Flashcards

MDE Unit 3 Chain and Belt driven camshaft timing, tappets

2. Chain Wear Examination

Question: What is the purpose of examining the wear of a chain in a chain-driven camshaft system?

C) To determine if the chain has stretched or elongated, affecting timing

Correcting Slight Loss of Timing Drive Tension

Question: How can slight loss of tension in engine timing belts or chains be corrected?

B) By adjusting the tensioner or idler pulleys to restore proper tension

5. Chain Lubrication Inspection

Question: What should be checked regarding chain lubrication during a camshaft drive inspection?

A) The amount of chain lubrication and its distribution

1. Chain Tension Check

Question: During a drive inspection of a chain-driven camshaft, why is it important to check the chain tension?

C) To prevent excessive wear and noise, and to ensure proper timing

Procedure for Setting Tappet Clearance

Question: What is the correct procedure for setting tappet clearance on diesel engine inlet/exhaust valves?

D) Measure the clearance with the engine cold, adjust the tappets using a feeler gauge, and then recheck the clearance with the engine at top dead center of the compression stroke.

2. Role of Rollers in a Timing Chain

Question: What role do rollers play in a timing chain system?

B) They reduce friction and wear between the chain and sprockets

6. Camshaft Gear Teeth Condition

Question: During a drive inspection, why should the condition of the camshaft gear teeth be examined?

A) To check for cracks or damage that might affect the gear's engagement with the chain

6. Timing of Valve Openings and Closings

Question: How is the timing of the valve openings and closings shown in a four-stroke timing diagram?

B) As overlapping lines representing the duration each valve is open or closed relative to the piston position

Importance of Tappet Clearances

Question: Why is maintaining proper tappet clearance important in an engine?

C) To ensure proper valve operation, avoid excessive wear, and maintain engine performance

1. Valve Operation during the Intake Stroke

Question: In a four-stroke engine timing diagram, what happens to the intake valve during the intake stroke?

B) The intake valve is open to allow air-fuel mixture into the cylinder

Components of a Timing Chain Link

Question: What components are typically found in a timing chain link?

A) Chain links, rollers, and side plates

3. Alignment of the Camshaft and Crankshaft

Question: Why is it important to check the alignment of the camshaft and crankshaft during a drive inspection?

C) To ensure proper timing and efficient engine operation

5. Timing of Fuel Injection

Question: In a four-stroke timing diagram, when does the fuel valve typically operate?

A) Just before the intake valve closes and the compression stroke begins

3. Valve Operation during the Power Stroke

Question: In a four-stroke engine timing diagram, what occurs with the valves during the power stroke?

C) The intake valve remains closed, and the exhaust valve remains closed

Four-Stroke Timing Diagram

Question: What does a four-stroke timing diagram illustrate?

B) The synchronization of valve openings and closings with the piston positions during the four-stroke cycle

2. Valve Operation during the Compression Stroke

Question: What is the position of the valves during the compression stroke in a four-stroke engine timing diagram?

B) The intake valve is closed, and the exhaust valve is closed

Purpose of Double (Nested) Valve Springs

Question: Why might double (nested) valve springs be fitted in a four-stroke diesel engine?

C) To prevent valve float at high engine speeds and ensure consistent valve operation

Effects of Loss of Timing Drive Tension

Question: How does a loss of tension in engine timing belts or chains affect the engine?

B) It can lead to incorrect valve timing, causing engine misfires and potential damage

6. Timing Chain Guide Purpose

Question: What is the purpose of the timing chain guide?

B) To guide the timing chain and prevent it from deviating from its path

Effects of Too Small Tappet Clearance

Question: What are the effects of having too small a tappet clearance on the exhaust valves of a four-stroke diesel engine?

B) Overheating of the valves, potential for incomplete valve closure, and increased wear on the valve train

4. Inspection for Chain Slippage

Question: How does checking for chain slippage contribute to the maintenance of a chain-driven camshaft system?

C) It detects if the chain has skipped teeth, affecting engine timing

4. Purpose of Timing Chain Sprockets

Question: What is the purpose of the sprockets in a timing chain system?

B) To guide and drive the timing chain, synchronizing engine components

5. Timing Chain Tensioner Function

Question: What is the role of the timing chain tensioner in the timing chain system?

B) To maintain the correct tension in the timing chain

3. Function of Side Plates in a Timing Chain

Question: What is the function of the side plates in a timing chain?

A) To keep the chain aligned and secure

Effects of Too Large Tappet Clearance

Question: What are the effects of having too large a tappet clearance on the exhaust valves of a four-stroke diesel engine?

B) Poor engine performance, increased valve train wear, and potential for valve damage

4. Valve Operation during the Exhaust Stroke

Question: What is the position of the valves during the exhaust stroke in a four-stroke engine timing diagram?

B) The intake valve remains closed, and the exhaust valve opens

1. Function of Timing Chain Links

Question: What is the primary function of the chain links in a timing chain system?

D) To transmit rotational motion between the sprockets

Meaning and Purpose of Valve Overlap

Question: What does the term "valve overlap" refer to, and what is its purpose in an engine?

B) Valve overlap refers to the period when both the intake and exhaust valves are open simultaneously. Its purpose is to enhance the engine’s performance by improving the scavenging of exhaust gases and increasing the intake of fresh air.

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