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Honing
Honing is carried out when liner gets glazed and looses it’s rough surface. Rough surface is required so as to sustain lube oil film so that there is a film between piston rings and liner to reduce friction and wear of both rings and liner. 

                      Honing is carried out by the help of silicon carbide tool which makes the surface rough and there is an increase in the diameter of the liner. This process of Honing is followed by a process named PLATEAU HONING which uses flex Jones which is like a brush with fine grains and revolve at a speed of 80-160 rpm. It makes a zig zag profile of 30 degree angle by moving vertically 1m/s which corresponds to about 2 sec for one double movement.

PLATEAU HONING removes only peaks , rough, torn and folded metal left by Honing process. It is called plateau finish as it is surface profile that resemble a series of plateau with harsh peak removed leaving flat finish with greater bearing area while maintaining a cross hatch pattern of valley for oil retention.

Liner Lacquering

It is the formation of a layer of lacquer on liner covering the Honing pattern, resulting in loss of oil control. It is mainly found in highly loaded engine with low sulpher gas oil. Lacquer probably originates partly due to decomposition of alkaline oil additives and partly due to decomposition at high pressure and temperature.

Phenomenon of Lacquering:-

When the fuel oil comes in contact with lub oil of high alkaline content then fuel react chemically with the alkaline of lub oil to form lacquer. Now due to high temperature the compound form burns and volatile part of the compound formed gets evaporated and leaving carbonic hard part. This hard part when rubbed with piston rings gets break and along with it some particles of liner also breaks leading to wear of liner.