G3508B, G3512B, G3512B, G3516B and G3520B Petroleum Engines Caterpillar

Installation Procedure

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Illustration 1	g00759331

1. Loosen the adjustment screws on valve bridges (4).

2. Place clean engine oil on the dowels for valve bridges (4), on the inside diameter of the valve bridges, and on the top buffer of the valve bridges.

3. Install valve bridges (4) on the dowels.

4. While valve bridges (4) are pushed straight down with a force of 5 to 45 N (1 to 10 lb), turn the adjustment screw until the screw makes contact with the valve stem. Turn the adjustment screw for an additional 20 or 30 degrees. This will align the valve bridge straight on the dowel. This also compensates for the slack in the threads of the adjustment screw.

5. Hold the adjustment screw in position and tighten the nut on the adjustment screw to a torque of 30 ± 4 N·m (22 ± 3 lb ft).

6. Apply Tooling (A) to the ends of pushrods (4).
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   NOTICE
   Ensure that the crankshaft and the camshafts are in time with each other. Also ensure that the adjustment screws in the rocker arms are loosened completely before the bolts on the rocker shaft are tightened or damage to the valves and the pistons may occur.

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   Illustration 2	g00759287

7. Install pushrods (3) in the valve lifters.

8. Install rocker shaft (2) on the valve cover base. Ensure that the rocker arms and the pushrods are aligned.

9. Install bolts (1). Tighten the bolts to a torque of 109 ± 14 N·m (80 ± 10 lb ft).

10. Set the valve lash on the intake valve to a clearance of 0.51 mm (0.020 inch). Set the valve lash on the exhaust valve to a clearance of 1.27 mm (0.050 inch).

11. Refer to the Testing and Adjusting Module, "Valve Clearance Setting" for more information.

End By:

1. Install the valve cover and the spark plug. Refer to Disassembly and Assembly, "Valve Cover and Spark Plug - Remove and Install".