CYLINDER WEAR MEASURED WITH A MICROSCOPE

AN instrument for the accurate measurement of cylinder wear is described by the authors. The instrument consists of a diamond indenting tool, an indentation locator, and a microscope.

To determine wear, the length of an indentation is observed with the microscope before and after periods of operation. Wear, which is reflected by changes in the depth of the indentation, is calculated from changes in the length of the indentation.

Using this instrument in their experiments, the authors found that most cylinder wear is due to corrosion and occurs during warmup, when cylinder temperatures are low. It appears that corrosive gases condense on cool cylinder walls and attack the surface. Then the corroded film and lubricating oil are wiped away by the piston, leaving the walls ready for further corrosion.