G3408C and G3412C Engines Caterpillar

For instructions on setting the valve bridge and the valve lash, refer to Systems Operation/Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment".

Illustration 1	g01519093

(1) Refer to Specifications, "Cylinder Head" for information that is related to the tightening sequence for the cylinder head bolts.

(A) Valve lash setting

Inlet valve ... 0.38 ± 0.10 mm (0.015 ± 0.004 inch)

Exhaust valve ... 1.07 ± 0.10 mm (0.042 ± 0.004 inch)

(2) Torque for nut ... 30 ± 4 N·m (265 ± 35 lb in)

Note: Tighten nut (2) after you set the valve lash.

(3) Torque for nut ... 47 ± 9 N·m (35 ± 7 lb ft)

(B) Bore in the rocker arm for the rocker arm shaft ... 24.803 mm (0.9765 inch)

(C) Height to top of the dowel ... 53.3 ± 0.8 mm (2.10 ± 0.03 inch)

(D) Dimensions for dowel

Diameter of new dowel ... 11.008 ± 0.003 mm (0.4334 ± 0.0001 inch)

Bore in valve bridge assembly for dowel ... 11.13 mm (0.438 inch)

Bore in cylinder head for dowel ... 10.968 ± 0.020 mm (0.4318 ± 0.0008 inch)

(4) The guide spring must not be used again. Always install new guide springs.

(E) Diameter of new lifter body ... 27.896 ± 0.013 mm (1.0983 ± 0.0005 inch)

Diameter of the valve lifter bore that is in the cylinder block ... 27.9527 ± 0.0190 mm (1.10050 ± 0.00075 inch)

Note: Lubricate the bore in the cylinder block for the valve lifter assembly with the 50/50 mixture of clean engine oil and 8T-2998 Lubricant before installation.

ReferenceRefer to Reuse And Salvage Guidelines, SEBF8069, "Procedure to Repair Lifter Bores for Engine" for more information.

Illustration 2	g01402710

(F) Diameter of new rocker arm shaft ... 24.752 ± 0.013 mm (0.9745 ± 0.0005 inch)

(G) Protrusion of the dowel above the top surface of the shaft bracket ... 10.0 ± 1.0 mm (0.40 ± 0.04 inch)

(H) Use the required number of washers (6) in order to obtain the end play for rocker arm to the following value. ... 0.30 to 1.40 mm (0.012 to 0.055 inch)

(5) 2N-7229 Spring

Length under test force ... 74.17 mm (2.920 inch)

Test force ... 44.5 to 53.4 N (10.0 to 12.0 lb)

Free length after test ... 114.3 mm (4.50 inch)

Outside diameter ... 29.76 mm (1.172 inch)