Generac Power Systems GN190H, Service And Repair Manual

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SECTION 11: CRANKSHAFT AND CAMSHAFT
43
CAMSHAFT INSPECTION
Carefully inspect the entire camshaft for wear, nicks or
other damage. All areas indicated in figure 11.4 should be
inspected.
Figure 11.4 — Points to Check on Camshaft
Carefully measure the following to check them for wear. If
wear limits are exceeded, replace the defective part.
CRANKSHAFT BEARING BORE
IN CRANKSHAFT COVER
DESIGN DIAMETER = 1.299-1.300 inch
(33.00-33.03mm)
CRANKSHAFT BEARING BORE
IN CRANKCASE
DESIGN DIAMETER = 1.024-1.025 inch
(26.00-26.03mm)
CRANKCASE SLEEVE BEARING
IN CRANKCASE
DESIGN DIAMETER = 1.104-1.106 inch
(28.044-28.099mm)
CRANKCASE BEARING BORE
IN CRANKCASE COVER
DESIGN DIAMETER = 1.103-1.105 inch
(28.030-28.058mm)
CAM LIFT AT BOTH CAM LOBES
DESIGN
LIFT = 0.210-0.212 inch
(5.34-5.38mm)
CAMSHAFT DIAMETER — FLYWHEEL END
DESIG
N DIAMETER = 1.022-1.023 inch
(25.96-25.98mm)
CAMSHAFT DIAMETER — PTO END
DESIG
N DIAMETER = 1.022-1.023 inch
(25.96-25.98mm)
CRANKSHAFT INSPECTION
CRANKSHAFT PROPER:
Using a commercial solvent, clean the crankshaft thor-
oughly. After cleaning, inspect the crankshaft as follows:
1. Inspect keyways in crankshaft (see Figure 11.5). Make sure
they are not worn or spread apart. Remove burrs from edges
of keyways, to prevent scratching the bearing.
2. Inspect the crankshaft gear for chipping or cracking. If
timing gear is damaged, the crankshaft must be replaced.
3. Inspect the crankpin for nicks, scratches or other damage.
Small scratches and nicks can be polished out using fine
emery cloth. ALL EMERY CLOTH RESIDUE MUST BE COM-
PLETELY REMOVED USING A SOLVENT (SUCH AS
KEROSENE).
4. Carefully measure the diameters of the crankpin, crankshaft
journal at flywheel end, and the crankshaft journal at PTO
end. Replace the crankshaft if it is worn beyond the stated
repair limits.
NOTE: The crankpin must NOT be ground to any smaller
diameter. Undersize connecting rods are NOT available.
CRANKPIN DIAMETER
DESIGN DIAMETER = 1.180-1.181 inch
(29.99-30.01mm)
CRANKSHAFT MAIN BEARING DIAMETER
FLYWHEEL END
DESIGN DIAMETER = 1.102-1.103 inch
(28.000-28.012mm)
CRANKSHAFT MAIN BEARING DIAMETER
PTO END
DESIGN DIAMETER = 1.102-1.103 inch
(28.000-28.012mm)
Figure 11.5 — Points to Check on Crankshaft
1
1. Check keyways
2. Crankshaft gear
3. Oil passage
4. Journal (flywheel end)
5. Journal (PTO end)
6. Crankpin
7. Threaded ends
2 3
4
5
6
7
1
1
2
3
4
5
6
1. Check spring pins
2. Camshaft gear
3. Compression release parts
4. Main bearing (flywheel end)
5. Main bearing (PTO end)
6. Cam lobes