3412 Generator Set Engines Caterpillar

Illustration 1	g01021344

(1) Tighten the bridge adjustment screw locknut to the following torque. ... 47 ± 9 N·m (35 ± 7 lb ft)

(2) Tighten the valve adjustment screw locknut after you set the valve lash.

Torque for the adjustment locknut ... 30 ± 4 N·m (22 ± 3 lb ft)

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

Exhaust valve lash (A) ... 0.76 ± 0.10 mm (0.030 ± 0.004 inch)

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

Bore in the rocker arm for the rocker arm shaft ... 24.803 ± 0.013 mm (0.9765 ± 0.0005 inch)

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

Diameter of the valve lifter bore that is in the cylinder block ... 27.953 ± 0.019 mm (1.1005 ± 0.0007 inch)

Reference: Special tooling, specifications, and procedures are needed to install sleeves in the cylinder block lifter bores. Refer to the Guideline for Reusable Parts, SEBF8069, "Salvage of Lifter Bores in 3400 Family Engines" for more information.

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

(4) 6N-6872 Guide Spring

Refer to the Guideline for Reusable Parts, SEBF8066, "Guide Springs for 3400 Series Engines" in order to obtain reuse information on guide springs.

Illustration 2	g01021949

(5) 2N-7229 Spring

Length under test force ... 74.2 mm (2.92 inch)

Test force ... 45 to 53 N (10 to 12 lb)

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

Outside diameter ... 29.7 mm (1.17 inch)

Protrusion of the dowel (F) above the top surface of the rocker shaft support ... 9.7 ± 1.0 mm (0.38 ± 0.04 inch)

Clearance for the rocker arms (G) ... 0.30 to 1.40 mm (0.012 ± 0.055 inch)

(6) 2N-7228 Washers should be added or removed in order to adjust clearance (G).