wsm STW37 - Piston and Connecting Rod

ENGINE
STW34, STW37, STW40, WSM
1-S71
(3) Piston and Connecting Rod
Piston Pin Bore I.D.
1. Measure the piston pin bore I.D. in both the horizontal and
vertical directions with a cylinder gauge.
2. If the measurement exceeds the allowable limit, replace the
piston.
9Y1211109ENS0113US0
Oil Clearance between Piston Pin and Small End Bushing
1. Measure the piston pin O.D. where it contacts the bushing with
an outside micrometer.
2. Measure the small end bushing I.D. with an inside micrometer,
and calculate the oil clearance.
3. If the oil clearance exceeds the allowable limit, replace the
bushing. If it still exceeds the allowable limit, replace the piston
pin.
9Y1211109ENS0114US0
Replacing Connecting Rod Small End Bushing
(When removing)
1. Press out the small end bushing with a connecting rod small end
bushing replacing tool.
(When installing)
1. Clean a new small end bushing and bore, and apply engine oil
to them.
2. Press fit a new bushing, taking due care to see that the
connecting rod hole matches the busing hole.
9Y1211109ENS0115US0
Piston pin bore I.D.
Factory specification
25.000 to 25.013 mm
0.98426 to 0.98476 in.
Allowable limit
25.05 mm
0.9862 in.
Oil clearance between
piston pin and small end
bushing
Factory specification
0.014 to 0.038 mm
0.00056 to 0.0014 in.
Allowable limit
0.15 mm
0.0059 in.
Piston pin O.D. Factory specification
25.002 to 25.011 mm
0.98433 to 0.98468 in.
Small end bushing I.D. Factory specification
25.025 to 25.040 mm
0.98524 to 0.98582 in.
(A) When removing (B) When installing
KiSC issued 11, 2014 A