LONG BLOCK M 20R5406 - Caterpillar

Note: The fuel injection pump must remain locked until the procedure instructs you to unlock the fuel injection pump.
Ensure that number one piston is at top dead center on the compression stroke. Refer to System Operation, Testing and Adjusting, "Finding Top Center for No. 1 Piston" for the correct procedure.
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If necessary, install the tooling.
Note: Do not use excessive force to install the tooling. Do not use the tooling to hold the crankshaft during repairs.
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Install the camshaft gear. Refer to Disassembly and Assembly, "Camshaft Gear - Remove and Install" for the correct procedure.
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Install the idler gear. Refer to Disassembly and Assembly, "Idler Gear - Remove and Install".
Check the end play of the idler gear. Refer to Specifications, "Gear Group (Front)".
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Check the end play of the camshaft gear. Refer to Specifications, "Camshaft" for more information.
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Use Tooling (F) to measure the backlash for the gears. Refer to Specifications, "Gear Group (Front)" for more information.
Lubricate each gear with clean lubricating engine oil.
If necessary, use Tooling (A) to rotate the crankshaft so that number one piston is at top dead center on the compression stroke. Refer to System Operation, Testing and Adjusting, "Finding Top Center Position for No.1 Piston" for the correct procedure. If necessary, use Tooling (B) to lock the crankshaft so that number one piston is at top dead center on the compression stroke.
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Failure to ensure that the crankshaft is positioned at 60 degrees after top dead center will result in interference between the pistons and the valves. Interference between the pistons and the valves will result in damage to the engine.
Use Tooling (A) to rotate the crankshaft in a clockwise direction and position the crankshaft at 60 degrees after top dead center.
Illustration 23 g06270146Note: When the threaded insert is tightened, the threaded insert must be seated correctly into the cup for the pushrod.
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The engine should not be operated for a period 30 minutes after the threaded inserts on all the rocker arms have been tightened. This period will allow the force from the valve springs to purge off excessive engine oil from the hydraulic lifters.
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Install the front cover.
Install the valve mechanism cover.