Liner Calibration Of Auxiliary Engine Onboard Ship

A cylinder liner is calibrated by measuring the internal diameter using a micrometer gauge.
It is routinely carried out during a unit overhaul when the running gear, cylinder head and piston have been removed.
So that the measurements can be directly compared to previous readings and a wear rate calculated, the position of the measurements is standardized by using a gauging point template (straight edge template), which in practice is a piece of flat bar hung over the side of the liner. The bar has holes drilled in it at the appropriate gauging points.
The liner should be gauged and be within the limits of wear given by manufacturer. (0.6 - 0.8% of original diameter).
Projected wear rate must be included in this assessment so that the liner will still be within limits at the next overhaul.
If the liner shows evidence of ovality or clover leafing then it should be honed to bring it back to circular shape before calibration.
Any signs of micro seizure should be investigated, and the lubrication restored to normal levels.
LINER CALIBRATION PROCEDURE
Before calibrating the liner remove the undulations and corrugations on the liner surface using a Flex honor
Fit a funnel below the liner to collect all the remnants produced while honing
Clean the liner and remove all the abrasive particles
Inspect the liner. Appearance of the liner surface shows whether the lubrication is adequate
Examine the combustion space for any surface cracks on the liner
Place the template on top surface of the liner, measure the inner diameter of the liner using an inside micrometer at the holes provided on the template.
Ensure that the temperature of liner and micrometer are same.
Take reading at different vertical positions in forward-aft and port-starboard directions with particular attention to combustion space.Record all the readings in the table format.