Cylinder Block Assembly: Service and Repair

NOTE: When boring cylinders, finish all cylinders to same oversize. Do not bore only one cylinder to an oversize.

1. It should depend on the largest bore cylinder which oversize piston to choose. Piston size identification mark for 0.50 mm (0.02 inch) oversize is 0.50 and 1.00 mm (0.04 inch) oversize is 1.00.

NOTE: Size mark is stamped on piston top.

2. Measure outside diameter of the chosen piston. Measure it in thrust direction as shown in the figure.
3. Based on measured piston outer diameter, calculate boring finish dimension. Boring finish dimension = Piston outer diameter + (clearance between piston outer diameter and cylinder) - 0.02 mm (0.0008 inch) (honing margin).

CAUTION: To prevent distortion that may result from temperature rise during honing, bore cylinders, working from No. 2 to No. 4 to No. 1 to No. 3.

4. Bore all cylinders to calculated boring finish dimension.
5. Hone to final finish dimension (piston outer diameter + clearance between piston outer diameter and cylinder).
6. Check the clearance between piston and cylinder. Clearance between piston and cylinder should be 0.03 - 0.05 mm (0.0012 - 0.0020 inch).