Generac 86640 - Manual (Page 41)

Section 2.6- ENGINE OVERHAUL
Disassembly
1. Place engine on workstand. Remove timing belt cover and
timing belt Remove cylinder head and oil pan. Remove
pistons.
2. Remove crankshaft rear oil seal retainer. Remove bearing
caps. Remove the crankshaft.
Inspection
1. Slide piston pin into piston'pin bore. At room temperature,
pin must slide smoothly into bore, without side play and
without binding. See Figure 53.
PISTON PIN TO PISTON CLEARANCE
0.0003*0.0005 Inch (0.008-0.012mm)
2. Check piston ring to groove side clearance (Figure 54).
Clearance should not exceed the maximum stated limit
RING TO GROOVE SIDE CLEARANCE
MAXIMUM LIMIT
Гор Ring = 0.0016-0.0029 inch (0.040-0.073mm)
2nd Ring = 0.0012-0.0025 inch (0.030-0.063mm)
Maximum
Tolerance=0.008 inch (0.2mrh)
Figure 53. Checking Piston Pin Fit
TOP RING
No. 1 Grades 0.0083-0.0118 Inch (0.21-0.30mm)
No. 2 Grades 0.0071-0.0118 Inch (0.18-0.30mm)
No. 3 Grades 0.0071-0.0118 inch (0.18-0.30mm)
2ND RINGS 0.0059-0.0154 Inch (0.15-0.39mm)
OIL RINGS 0.0079-0.0311 inch (0.20-0.79mm)
4. Use Plastigage" to check bearing clearance (Figure 56).
Comply with the following:
Page 2.6-1