Oil Pump - wsm STW37 Workshop Manual

STW34, STW37, STW40, WSM

(6) Oil Pump

Correcting Cylinder (Oversize +0.25 mm)
1. When the cylinder is worn beyond the allowable limit, bore and
hone it to the specified dimension.
Oversize cylinder I.D. Factory specification
Maximum wear Allowable limit
Horn to 2.2 to 3.0 µm Rmax.
Finishing
(0.00087 to 0.00118 in. Rmax.)
2. Replace the piston and piston rings with oversize ones.
Oversize: 0.25 mm (0.0098 in.).
NOTE
• When the oversize cylinder is worn beyond the allowable
limit, replace the cylinder block with a new one.
(1) Cylinder I.D. (Before Correction)
Rotor Lobe Clearance
1. Measure the clearance between lobes of the inner rotor and the
outer rotor with a feeler gauge.
2. Measure the clearance between the outer rotor and the pump
body with a feeler gauge.
3. If the clearance exceeds the factory specifications, replace the
oil pump rotor assembly.
Factory specification
Clearance between inner
rotor and outer rotor
Allowable limit
Factory specification
Clearance between outer
rotor and pump body
Allowable limit
Clearance between Rotor and Cover
1. Put a strip of plastigauge (Code No. 07909-30241) onto the
rotor face with grease.
2. Install the cover and tighten the screws.
3. Remove the cover carefully, and measure the width of the press
gauge with a sheet of gauge.
4. If the clearance exceeds the factory specifications, replace the
oil pump rotor assembly.
Factory specification
End clearance between
inner rotor and cover
Allowable limit
1-S78
ENGINE
87.250 to 87.272 mm
3.4351 to 3.4359 in.
87.400 mm
3.4409 in.
(2) Oversize Cylinder I.D.
9Y1211109ENS0128US0
0.03 to 0.14 mm
0.0012 to 0.0055 in.
0.2 mm
0.008 in.
0.11 to 0.19 mm
0.0043 to 0.0075 in.
0.25 mm
0.0098 in.
9Y1211109ENS0129US0
0.105 to 0.150 mm
0.00414 to 0.00590 in.
0.2 mm
0.0079 in.
9Y1211109ENS0130US0
KiSC issued 11, 2014 A