Briggs & Stratton 405777 Series - Crankshaft and Camshaft; Crankshaft Inspection and Grinding; Camshaft Inspection

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9905 1
Section 11
Crankshaft And Camshaft
Page
Checking Crankshaft 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking Cam Shaft 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section Contents
Checking Crankshaft
Inspect crankshaft threads and keyways for damage or
wear. If threads or keyways are damaged or worn, replace
crankshaft. Check journals for scoring. If journals are
scored, replace crankshaft. Check journals for wear. See
crankshaft reject sizes.
Crankshaft Reject Sizes
Model
Series
PTO
Journal
Mag.
Journal
Crankpin
Journal
405770
1.623”
(41.22 mm)
1.376”
(34.95 mm)
1.4965”
(38.01 mm)
Check oil galleries for blockage or obstructions. Check
timing gear for damaged teeth. Timing gear is replaceable.
See illustrated parts list.
Crankshaft crankpin may re-ground for .020” undersize
connecting rods, Fig. 2. See illustrated parts list for part
number. See crankshaft grinding dimensions.
Crankshaft Grinding Dimensions
Dim. A
Dim. R Dim. T
1.4782/1.479”
(37.54/37.56 mm)
.170/.180”
(4.32/4.57 mm)
1.4435/1.4465
(36.66/36.74 mm)
Checking Cam Shaft
Inspect gear teeth, lobes and journals for wear and nicks,
Fig. 3. Check oil galleries for blockage or obstructions.
Camshaft journal and lobe reject sizes are shown below.
Replace cam gear if not to specification.
Camshaft Reject Size
Journals
(Mag & PTO)
Intake
Lobes
Exhaust
lobes
.623”
(15.82 mm)
1.225”
(31.15 mm)
1.223”
(31.06 mm)
Fig. 1 − Checking Crankshaft
TIMING GEAR TEETH
P.T.O. JOURNAL
KEYWAY
THREADS
AND
KEYWAY
MAG. JOURNAL
CRANKPIN
OIL
GALLERIES
OIL
GALLERIES
Fig. 2 − Crankshaft Dimensions
R
A
T
GEAR TEETH
Fig. 3 − Checking Camshaft
MAG.
JOURNAL
INTAKE LOBES
EXHAUST LOBES
OIL GALLERY
P.T.O.
JOURNAL
TSM