Wacker Neuson WM 90, Repair Manual

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WM 90 Repair Reassembly Procedures
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8.9 Cylinder Head
8.9.1 Clean carbon and gum deposits from the valves, seats, ports, and
guides. Inspect them once clean. Replace valves that are badly
burned, pitted, or warped.
8.9.2 When installing valves in cylinder head, oil the valve stems and insert
them into valve guide. Then place cylinder head on a flat table, install
spring and spring retainer.
8.9.3 Valve guides should be replaced when valve stem clearance exceeds
specifications. See Clearance Data and Limits Table.
8.9.4 Draw valve guides out and press new guides in. See Clearance Data
and Limits Table.
8.9.5 After replacing valves and guides, lap valves in place until a uniform
ring shows around the face of the valve. Clean valves and wash
cylinder head thoroughly.
8.9.6 Install cylinder head onto cylinder with new head gasket. Tighten the
four M8 x 55 flange bolts in a crisscross pattern, in three incremental
steps using the following torque values:
Step 1: 5.0 Nm (3.6 ft.lbs.)
Step 2: 9.8 Nm (7.2 ft.lbs.)
Step 3: 18.6–20.6 Nm (13.7–15.2 ft.lbs.)