Weichai America Corp.
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Fig. 2-17 Individual Cylinder Head Tightening Order
2. The cylinder head bolt will stretch and deform between 0.2~0.6mm after tightening. The bolt
can’t be reuse if the length over 160.5mm.
3. Install the valve oil seal.
Key point 2:
Inspection
Clean the cylinder head, focusing on the combustion chamber surface, valve seat, intake and
exhaust valves, and intake and exhaust passages. Remove the carbon deposits and mucilage glue,
and check the surface condition.
1. Appearance Inspection:
Check the cylinder cover for any discoloration or cracks. If any cracks are discovered, a leak test
should be done.
2. Valve Recession:
Valve recession is the vertical distance between valve undersurface and cylinder cover
undersurface. Any difference between the measured and required values of valve recession can
reflect the degree of wear on the valve and valve seat. A depth micrometer can be used to
measure valve recession, as shown in Figure 2-18 below:
