Oversize Bore
Oversize pistons and rings are available in one size - 0.50 mm (0.0197 inch).
Any combination of standard or 0.50 mm (0.0197 inch) overbore may be used in the same engine.
If more than 0.50 mm (0.0197 inch) overbore is needed the block must be replaced.
Cylinder block bores may be bored one time. The bore size is 0.50 mm (0.0197 inch) oversize.
After boring to size, use a honing stone to chamfer the edge of the bore.
| DESCRIPTION | MEASUREMENT |
|---|---|
| BORING DIAMETER DIMENSION | REBORE - 107.490 mm (4.2319 in.) Minimum |
| REBORE - 107.510 mm (4.2327 in.) Maximum | |
| HONING DIAMETER DIMENSIONS | STANDARD - 102.020 ± 0.020 mm (4.0165 ± 0.0008 in.) |
| REBORE - 107.45 mm (4.2303 in) Nominal | |
| CHAMFER DIMENSIONS | Approx. 1.25 mm (0.049 in.) by 30° |
A correctly honed surface will have a crosshatch appearance with the lines at 15° to 25° angles with the top of the cylinder block. For the rough hone, use 80 grit honing stones. To finish hone, use 280 grit honing stones.
A maximum of 1.2 micrometer (48 microinch) surface finish must be obtained.
After finish honing is complete, immediately clean the cylinder bores with a strong solution of laundry detergent and hot water.
After rinsing, blow the block dry.
Check the bore cleanliness by wiping with a white, lint-free, lightly-oiled cloth. There should be no grit residue present.
If the block is not to be used right away, coat it with a rust- preventing compound.