wsm STW37 Workshop Manual page 151

STW34, STW37, STW40, WSM
Connecting Rod Alignment
NOTE
• Since the I.D. of the connecting rod small end bushing is
the basis of this check, check bushing for wear
beforehand.
1. Install the piston pin into the connecting rod.
2. Install the connecting rod on the connecting rod alignment tool.
3. Put a gauge over the piston pin, and move it against the face
plate.
4. If the gauge does not fit squarely against the face plate,
measure the space between the pin of the gauge and the face
plate.
5. If the measurement exceeds the allowable limit, replace the
connecting rod.
Connecting rod
Allowable limit
alignment
Piston Ring Gap
1. Insert the piston ring into the lower part of the liner (the least
worn out part) with the piston.
2. Measure the ring gap with a feeler gauge.
3. If the gap exceeds the allowable limit, replace the ring.
Factory specification
Top ring
Allowable limit
Second ring Factory specification
Second ring Allowable limit
Factory specification
Oil ring
Allowable limit
Clearance between Piston Ring and Groove
1. Remove carbon from the ring grooves.
2. Measure the clearance between the ring and the groove with a
feeler gauge or depth gauge.
3. If the clearance exceeds the allowable limit, replace the ring
since compression leak and oil shortage result.
4. If the clearance still exceeds the allowable limit after replacing
the ring, replace the piston.
Factory specification
Second ring
Allowable limit
Factory specification
Oil ring
Allowable limit
1-S72
ENGINE
0.05 mm
0.002 in.
9Y1211109ENS0116US0
0.25 to 0.40 mm
0.0099 to 0.015 in.
1.25 mm
0.0492 in.
0.30 to 0.45 mm
0.012 to 0.017 in.
1.25 mm
0.0492 in.
0.25 to 0.45 mm
0.0099 to 0.017 in.
1.25 mm
0.0492 in.
9Y1211109ENS0117US0
0.0930 to 0.128 mm
0.00367 to 0.00503 in.
0.2 mm
0.0079 in.
0.020 to 0.060 mm
0.00079 to 0.0023 in.
0.15 mm
0.0059 in.
9Y1211109ENS0118US0
KiSC issued 11, 2014 A