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Class 2 (2nd Engineer) MEKM 📅 Jul 2021

Exam Question

With reference to medium speed engine cylinder liners:

(a) Explain the cause and effects of polishing or glazing

(b) Describe, with the aid of sketches, an anti-polishing ring and explain how it is fitted in the liner

(c) Explain the action of an anti-polishing ring during the operation of the engine.

Exam question diagram

Reference Answer

(a) Polishing or Glazing in Cylinder Liners:
Causes:
Polishing or glazing of cylinder liners in medium-speed engines primarily occurs due to the burning of residual fuel, which leaves unburnt carbon deposits around the topland of the piston. These abrasive carbon deposits remove the lubricating oil film, leading to increased wear. Additionally, as the liner surface becomes polished, it develops a glazed texture that prevents the lubricating oil from adhering properly, resulting in metal-to-metal contact and further abrasion.
Other causes include:

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