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Measuring Critical Components
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PISTON SKIRT/CYLINDER CLEARANCE 127( &ULWLFDO HQJLQH FRPSRQHQW VSHFLILFDWLRQV DUH RQ SDJHV RI WKLV VHFWLRQ
1. Measure each cylinder front to back about 2.5 cm (1 in.) from the bottom of each cylinder.
CYLINDER TRUENESS
2. Measure the corresponding piston skirt diameter at a point 1 cm (0.394 in.) above the piston skirt at a right angle to the piston-pin bore. Subtract this measurement from the measurement in step 1. The di ff e r ence (clearance) must be within specifications.
1. Measure each cylinder in the three locations from front to back and side to side for a total of six readings. )LJ
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2. The trueness (out-of-roundness) is the difference between the highest and lowest reading. Maximum trueness (out-of-roundness) must not exceed specifications.
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PISTON-RING END GAP
1. Place each piston ring in the wear portion above the exhaust port of its respective cylinder. Use the piston to position each ring squarely in each cylinder. 2. Using a feeler gauge, measure each piston-ring end gap. Acceptable ring end gap must be within specifications.