WEICHAI WD10 Service Manual - page 55
Service Manual for WD10 Diesel Engine
45
Fig. 4-8 Depth micrometer
Refer to Table 4-1 for valve recession requirements. If valve recession exceeds allowed range,
check wear condition of valve and valve seat, replace the valve with a new one to determine wear
condition of valve seat by measuring the valve recession again, if the valve recession still exceeds
allowed range, the cylinder cover must be replaced to ensure reliability of diesel engine. If valve
recession doesn’t exceed allowed range, disassemble the valve to check the sealing surface between
valve and valve seat for obvious wear and abnormal damage.
Table 4-1 Valve recession requirements:
Required value of
valve recession (mm)
Intake valve
0.85~1.05
Exhaust valve
1.08~1.48
(4) After disassembling valve mechanism, check cylinder cover intake and exhaust passage for
water leakage and other problem, if leakage is discovered, liquid penetrant test should be done
after cleaning to locate the problem, replace the cylinder cover.
(5) Clean cylinder cover, focus on combustion chamber surface, valve seat, intake and exhaust valve,
intake and exhaust passage, remove the carbon deposit and mucilage glue, and check the surface
condition.
(6) Check valve guide pipe inner diameter. Due to internal surface of valve guide pipe is the
contacting surface between valve rod and valve guide pipe, if clearance between valve rod and
valve guide pipe exceeds allowed value due to abrasion, then the guide effect will at state,
which may affect reliability of the engine. The inner diameter of guide pipe can be measured
with an inside micrometer, as shown in Fig. 4-9. Allowed range for inner diameter of guide
pipe is 11~11.018mm. If it exceeds allowed range, the cylinder cover must be replaced to
ensure reliability of diesel engine.
Fig. 4-9