Cylinder-Boring

Fig. 14

Examine cylinder walls for scuffs, scoring and measure cylinder bore for out-of-round or taper. If defective, bore cylinder to oversize. Measure at points shown in (Fig. 14).
Four oversize pistons are available (0.25 mm (0.010 inch) 0.50 mm (0.020 inch) 0.75mm (0.030 inch) and 1.0mm (0.039 inch). Determine oversize piston on basis of largest cylinder bore.





Fig. 15

1. Bore to specified clearance between the piston O.D. and cylinder. The measuring point of the piston O.D. is shown in (Fig. 15).
2. Based on measured piston O.D., calculate boring finish dimension. Boring finish dimension equals piston O.D. plus 0.03 to 0.05 mm (0.0012 to 0.002 inch) (clearance between piston O.D. and cylinder) minus 0.02 mm which is the boring margin.
3. Bore all cylinders to calculated boring finish dimension. Then bore the final finish dimension (piston O.D. plus cylinder clearance).
4. Check clearance between piston and cylinder, clearance should be 0.02 to 0.04 mm (0.0008 to 0.0016 inch).