Class 2 (2nd Engineer) MEKM 📅 Dec 2020

Exam Question

With reference to medium speed engine cylinder liner:

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

(b) Describe with the aid of sketches, an anti-polishing ring;

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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