Cylinder Head And Valves - Kubota ZD221-48 Workshop Manual

ZD221 , WSM
EI\JGINE
[4] SERVICING
(1) Cylinder Head and Valves
Top Clearance
(1 )
1. Remove the cylinder head. (Do not attempt to remove the
cylinder head gasket.)
2. Move the piston up and stick a strip of fuse [1.5 mm dia. (0.059
in. dia.), 5 to 7 mm long (0.197 to 0.276 in. long)] on the piston
head at three positions with grease so as to avoid the intake and
exhaust valves and the combustion chamber ports.
3. Lower the piston, and install the cylinder head and tighten the
cylinder head screws to the specified torque.
4. Turn the flywheel until the piston exceeds top dead center.
3EEABAB1P057B
3TMABABl P023B
5. Remove the cylinder head, and measure the thickness of the
squeezed fuses.
6. If the measurement is not within the factory specifications, check
the oil clearance between the crankpin and crankpin bearing and
between the piston pin and small end bushing .
• NOTE
• After checking the top clearance, be sure to assemble the
cylinder head with a new cylinder head gasket.
to 0.70 mm
Top clearance Factory spec.
o
to 0.027 in.
lightening torque Cylinder head screw
38 to 42 N'm
3.8 to 4.3 kgf-m
28
to 311bHt
3TMABABl P056A
(1) Fuse (2) Fuse
Cylinder Head Surface Flatness
1. Clean the cylinder head surface.
Wl020190
2. Place a straightedge on the cylinder head's four sides and two
diagonal as shown in the figure.
3. Measure the clearance with a thickness gauge.
4. If the measurement exceeds the allowable limit, correct it with a
surface grinder.
• IMPORTANT
• Do not place the straightedge on the combustion chamber.
• Be sure to check the valve recessing after correcting.
3EEABABl Pl12B
Cylinder head surface 0.05mm
Allowable limit
flatness 0.002 in.
Wl027737
1-S40