IHI NIIGATA MG(L)26HLX, Инструкция по эксплуатации

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SECTION
４
- DISASSEMBLY AND REASSEMBLY
4.1 CYLINDER HEAD AND VALVE MECHANISM
４－１－０５
4.1.3 Valve Removal and Inspection
CAUTION
When disassembling the spring section during the course of overhaul inspection,
parts are caused to jump out due to disengagement of disassembly tools.
Thus, there is a danger of injuries. Familiarize yourselves with the construction of
component and use tools properly. Also give care full attention to the jumping
direction of parts so that the body will be kept away from the jumping direction.
- Place the cylinder head on a flat surface so that the bottom of the valves
are supported (to prevent them from falling when the springs are removed).
- Install the retainer removal tool. Tighten the nut
①
enough to compress
the valve springs and remove the keepers from the valve retainers. Remove
the tool, remove the retainers, and position the cylinder head on its side
to remove the valves.
- Mark the valves with the cylinder number and position (intake or exhaust)
so that they can be reinstalled in the same position.
- Clean the valves carefully with a non-metallic scraper, mild steel wool, or
a descaling agent. Avoid scratching the valve surfaces.
- The valve stems must be free from scratches or scuff marks and the valve
faces must not be cracked or pitted. Check the contact between the valve
face and the valve seat by coating the valve seat with Prussian Blue (or
equivalent) and reinstalling the valve (do not rotate the valve). A full
360 degrees contact line should appear approximately centered on the valve
face. If not, the valves should be reface (instructions below) or new
valves installed. Measure the stem diameters (Refer to Clearance and Wear
Tables) and install new valves if the maximum wear limits are exceeded.