ENGINE
L3301, L3901, L4701, WSM
1-S62
7. SERVICING
[1] CYLINDER HEAD AND VALVES
Top Clearance
1. Remove the cylinder head.
2. With the piston at TDC, use grease to affix three or four
plastigauges (1) of a diameter 1.5 mm (0.059 in.) × 5.0 to
7.0 mm (0.20 to 0.27 in.) long to the crown of the piston; keep
the gauges away from the intake valve and combustion
chamber fittings.
3. Take the piston to an intermediate position, install the cylinder
head and tighten the head screws to the specified torque.
4. Turn the crankshaft so the piston goes through TDC.
5. Remove the cylinder head and compare the width of the
crushed plastigauges (2) with the scale (3).
6. If they are out of spec, check the oil clearance of the crank pin,
journals and piston pin.
• Top clearance = Width of the crushed plastigauge (2).
9Y1211012ENS0070US0
Cylinder Head Surface Flatness
1. Clean the cylinder head surface.
2. Put a straightedge on the cylinder head.
3. Measure the clearance with a feeler gauge at the 6 places (see
the figure).
4. If the measurement is more than the allowable limit, make it
straight with a surface grinder.
• Do not put a straightedge on the combustion chamber.
• Check the valve recessing after you correct.
9Y1211012ENS0071US0
Top clearance Factory specification
0.60 to 0.70 mm
0.024 to 0.027 in.
Tightening torque
Cylinder head mounting
screw
93.2 to 98.0 N·m
9.50 to 10.0 kgf·m
68.8 to 72.3 lbf·ft
(1) Plastigauge
(2) Crushed Plastigauge
(3) Scale
Cylinder head surface
flatness
Allowable limit
0.05 mm
0.002 in.
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