NEXON BS VI - SERVICE MANUAL

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1.2L REVOTRON ENGINE
63
I. Piston and Piston Rings
1. Remove carbon deposits, if any, from the
piston.
2. Clean piston and piston rings using
appropriate cleansing agent.
NOTE
 The piston and piston rings can be reused
if the bore taper and sphericity is within the
specified limits.
 Carefully examine the piston rings for
cracks, scoring, ring groove/ clip groove
wear, piston pin bore wear.
 In case anyone piston is found to have any
one of the above defects, replace the
complete piston set.
3. Check for lateral clearance in piston ring
groove.
4. Check for butt clearance in cylinder bore.
5. Check for piston pin dimensions.
NOTE
 Butt clearance of piston ring is measured in
unworn portion of the cylinder bore.
 Piston and piston rings of appropriate size
should be used, if cylinder bores are re-
bored.
 If piston ring is found to be defective as
started above, then complete ring set
should be replaced.
Details Specification (mm)
Piston pin diameter 19.997-20.000
Piston pin length 45.0 -0.3
Height of piston 51.89
Piston to bore
clearance
0.055/0.075
Piston Pin Bore in Piston (mm)
Grade Hole ø
1 20.005-20.008
2 20.008-20.011
3 20.011-20.014
Piston and Cylinder Bore Sizes (1.2L NG TC REVOTRON)
Type Grade Cylinder Bore Dia. (mm) Piston Dia. (mm)
Standard
A 77.015/77.025 77.020 ±0.005mm
B 77.025/77.035 77.030 ±0.005mm
Piston Rings (1.2L NG TC REVOTRON)
Type of ring Ring Thickness (mm) Axial Clearance in
Piston Groove (mm)
Butt Clearance in
Cylinder Bore (mm)
1st Compression Ring 1.2 -0.010 / -0.030 mm 0.06/0.1 0.17/0.32
2nd Compression Ring 1.2 -0.005 / -0.030 mm 0.05/0.09 0.4/0.6
3rd Oil Control Ring 2.0 -0.030 / -0.130 mm 0.06/.014 0.2/0.7