93.AE Liner calibration

Cylinder liner has to be gauged at regular intervals as specified in the maintenance manual. The records of gauging are kept for each cylinder and the wear rate is calculated.

Generally while taking the measurement the temperature of the liner and micrometer should be kept
at the same temperature. If the temperature exceeds than that of the liner or vice versa then the readings have to be corrected by multiplying the value with the correction factor and deducting the value obtained from the reading taken. The reading obtained at the end will be the correct readings.

The cylinder liner wear is measured by a standard template, which consists of strategically positioned

holes, wherein the micrometer is placed and the readings are taken. The readings are taken for both port - starboard and forward - aft positions.

This is done because the wear is not same in both directions and the ovality is to be checked. The wear rate will be different in the liner. The wear will be more in the top one third part as combustion

takes place there and temperatures and pressures are also very high at the top.

An approximate normal wear rate of the liner is about 0.1 mm per 1000 running hours.

The wear rate increases if the engine is overloaded. Generally the liner has to be replaced when the wear is about 0.6-0.8% of the bore diameter or as per the manufacturer’s recommendation.