Q3 (16 Marks) Engine Construction & Components 🔥 Repeated 3x in exams
MEP • Written Exam

(a) State the circumstances owing to which it may be necessary to renew a cylinder liner.

(b) Explain how the liner is removed.

(c) Explain how the new liner is fitted.

State the important checks to be made after fitting.

Appeared In: Nov 2025Oct 2018Jun 2018

Verified Model Answer (Text Solution)

Structured for DG Shipping MEO Class II examination scoring criteria.

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Part (a)

There are several circumstances under which it may be necessary to renew a cylinder liner in an engine. One of the primary reasons is excessive wear of the liner, which can lead to issues such as blow past, where combustion gases escape past the piston rings, and incomplete combustion, both of which can affect engine performance

Excessive wear down of liner leads to troubles like blow past incomplete combustion. Liner wear can be of the following types:

  • Frictional wear: It is due to the sliding over of two surfaces and depends on the speed of movement between surface, material, temperature, load of engine, lubrication, etc

  • Corrosive wear: it is due to the burning of fuel in combustion space. High sulphur content in fuel oil will lead to the formation of sulphuric acid due to the absorption of condensate/ moisture present inside the combustion space.
    This acidic corrosion is found more in the lower part of the liner as the temperature of JCW is low in this region. This wear near the quills enlarges and a CLOVE LEAF shape is formed and the phenomenon is known as CLOVER LEAFING

  • Abrasive wear: it is due to the hard particles present and formed during combustion

  • Adhesive wear/ scuffing: Local welding between piston and liner surface due to insufficient lubrication and high temperature

2. Cracks:

  • Insufficient Cooling: High temperatures can cause the liner to expand and crack, especially when cooling systems are inadequate.
  • Excessive Tightening of Cylinder Head Studs: Improper tightening can cause stress on the liner and lead to cracks.
  • Flame Impingement: Direct contact of the combustion flame with the liner can create localised heating and result in star-shaped cracks.

3. Seizure:

  • Insufficient Cooling: Similar to cracking, lack of cooling can lead to overheating and seizing of the piston within the liner.
  • Improper Lubrication: Insufficient or contaminated lubricant can lead to increased friction and eventually seizing.



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