Inspect And Repair; Cylinder Head; Rocker Shaft Assembly; Camshaft - Yale GDP16-20AF Maintenance Manual

Cylinder Head, Camshaft, and Valve Mechanism Repair

INSPECT AND REPAIR

Cylinder Head

Use straight edge and thickness gauge to check bottom
surface of cylinder head for distortion. Do the measure-
ments at the positions shown in Figure 8.
Maximum amount of distortion is 0.15 mm (0.0059 in.).
If grinding of cylinder head is necessary, maximum
amount of correction is 0.2 mm (0.008 in.).
Figure 8. Cylinder Head Inspection

Rocker Shaft Assembly

1. Disassemble rocker shaft assembly. Put marks on
rocker arms so they can be installed on correct
shafts.
2. Clean oil passages in rocker shafts and rocker
arms.
3. Check clearance between rocker arms and rocker
shafts. Maximum clearance is 0.10 mm (0.004 in.).
Correct dimension for inside diameter of rocker
arm is 16.000 to 16.027 mm (0.6299 to 0.6311 in.).
Correct dimension for outside diameter of rocker
shaft is 15.966 to 15.984 mm (0.6286 to 0.6293 in.).
If components do not meet specifications, replace
rocker arm(s) or rocker shaft(s) as necessary.
4

Camshaft

1. Check camshaft for cracks or damage.
2. Use dial indicator on end of camshaft to check
movement of camshaft in cylinder head. See Fig-
ure 9. Maximum movement is 0.20 mm (0.008 in.).
Figure 9. Camshaft Check
3. Measure height of camshaft lobes. See Figure 10.
Minimum height of intake and exhaust lobes is
36.902 mm (1.4528 in.).
4. Measure camshaft journals at four points (A-D) as
shown in Figure 10. Minimum dimensions for the
journals are as follows:
Front and Rear Journals (Nos. 1 and 5) - 31.940
to 31.965 mm (1.2575 to 1.2585 in.)
Center Journals (Nos. 2, 3 and 4) - 31.910 to
31.935 mm (1.2563 to 1.2573 in.)
Front Oil Seal Surface - 33.961 to 34.000 mm
(1.3371 to 1.3386 in.)
Fuel Pump Lobe - 37.1 mm (1.46 in.)
5. Check camshaft for straightness. Put front and
rear journals in V blocks and rotate camshaft one
complete turn. See Figure 11. Maximum amount
that the dial indicator should indicate is 0.03 mm
(0.0012 in.).
6. Measure clearance between camshaft and bore in
cylinder head as follows:
a. Install camshaft in cylinder head.
600 YRM 496