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17.Crankcase
Preparation documents-----------------17.1
Failure diagnosis-----------------17.2
Crankcase-------------------17.3
Installation--------------------17.4
17.1 Preparation documents
Note
The crankcase is thin-section casting thus has to avoid shock on operation in case of deformation and fracture.
All components must be cleaned and dried with high-pressure gas before test.
The lubricant in the crankcase should be released before operation.
Function of the crankcase: The crankcase is the force-bearing part of the engine. Its main function is
bearing crankshaft, clutch, transmission case, cylinder body and cylinder head, bearing the inertia force from
combustion shock and the movement of crankshaft connecting rod system, and forming a closed space(oil sealing,
gas sealing)
There are suspension holes in the crankcase, connecting the engine to other parts of the body through the
connection with suspension holes in the car circuit.
Preparation standard unit:mm
Item Standard value Usage limit
Left-right clearance of rod big end 0.25-0.40 0.55
Crankshaft
Radial clearance of rod big end 0.015-0.025 0.05
Tools
Universal holder spring compressor of the clutch
Screwdriver lever sleeve spanner
Guide rod bearing driver
17.2 Failure diagnosis
Noise in crankcase