Determining the piston clearance the correct usage of the measuring tool is very important. It is common to measure a piston with the suitable micrometer 90° to the piston pin axis in the middle or below at the piston shirt. Of course, it is crucial to keep the suitable temperatures for both the tools and the material. Before measuring the cylinder, the inside caliper must be calibrated, actually, with suitable measuring pieces. However, you may also determine a value and measure it out with another measuring tool. It is important to perform a measurement on top, the middle and below crosswise to the crankshaft stack axis. The biggest wear may be expected on top in the return point.
The sequence of pictures above displays the realization first. Also the usage of the inside caliper can generate mistakes. Therefore, the smallest value with slight tipping movements should be regarded. Picture 2 shows the different, calibrated distance pieces with which probably every length can be composed. Figure 3 displays the - again calibrated - rail in which an exactly defined length is left for the dial gauge with inside caliper.