Xinchai 490B Series Manual page 32

The method of adjusting valve clearances is as follows:
1尧 Take off the cylinder head cover, check and fasten the bolts which hold the rocker
bracket.
2尧 Turn round the crankshaft until the first piston is at its top dead center when the
mark at the observing window on the flywheel housing is just in line with the "0"mark on
the flywheel, or the indicating pin on the gear housing cover is just pointing to the "0"
mark on the V belt pulley.
3尧 Measure the intake and exhaust valve clearances of the
first cylinder with a feeler gauge. Adjust them to 0.35mm and
0.45mm respectively in cold state. Then turn the crankshaft
for 180毅 CA to adjust the other cylinders忆 valve clearances.
Adjustment done as follows:
荫 Take off the cylinder head cover
荫 Shut down the engine and wait for 30 minutes before
adjusting valve clearances.
Oil temperature should be below 80 益.
荫 Using the feeler gauge to check the valve clearances between 于 and 盂.
Adjust the valve clearances in following steps:
1尧 Loosen nut 榆
2尧 Turn bolt虞 with a screwdriver and tighten nut 榆 to get correct valve clearances.
3尧 Check and adjust other valve clearances.
4尧 Install cylinder head cover
Adjust the valves marked 预 in the table.
Cylinder Number
Valve Exhaust Intake Exhaust Intake Exhaust Intake Exhaust Intake
Rocker Number
Compression
TDC of No.1
Cylinder
Cylinder Number
Valve Exhaust Intake Exhaust Intake Exhaust Intake Exhaust Intake
Rocker Number
Compressing
TDC of No.4
Cylinder
28
窑 窑
1
1 2 3
预 预
1
1 2 3
预
2 3
4 5
预 预
2 3
4 5
4
6 7 8
4
6 7 8
预 预 预