What is a Tachometer Drive and where is it located on a C12 Caterpillar engine?

  • How do you run overhead on a c12 cat engine?

    Finding TDC Remove two bolts (1) and remove cover (2) from flywheel housing (3) in order to open the turning hole.Put one 6V-5219 Bolt (1) in the timing hole. The timing hole is located approximately 127 to 152 mm (5.0 to 6.0 inch) above the turning hole in the flywheel housing. Use the 9S-9082 Engine Turning Tool and a 1U-7115 Reverse Ratchet to turn the engine flywheel. Turn the flywheel in the direction of engine rotation. The direction of engine rotation is counterclockwise, as the engine is viewed from the flywheel end. Turn the flywheel until the timing bolt engages with the threaded hole in the flywheel. Note: If the flywheel is turned beyond the point of engagement, the flywheel must be turned in the direction that is reverse of normal engine rotation. Turn the flywheel by approximately 30 degrees. Then turn the flywheel in the direction of normal rotation until the timing bolt engages with the threaded hole. This procedure removes the play from the gears when the No. 1 piston is at the top center position.Remove the front valve mechanism cover from the engine.The inlet and exhaust valves for the No. 1 cylinder are fully closed if No. 1 piston is on the compression stroke and the rocker arms can be moved by hand. If the rocker arms cannot be moved and the valves are slightly open, the No. 1 piston is on the exhaust stroke. Note: When the actual stroke position is identified, and the other stroke position is needed, remove the timing bolt from the flywheel. Then turn the flywheel by 360 degrees in the direction of normal engine rotation and reinstall the timing bolt. Injector adjustment To make an adjustment to the unit injectors on cylinders 3, 5, and 6 use the following procedure:Put the number 1 piston at the top center position on the compression stroke. Refer to Systems Operation/Testing and Adjusting, “Finding Top Center Position For No. 1 Piston”.Turn the unit injector adjusting screw (2) clockwise until contact is made with the unit injector.Turn the unit injector adjusting screw through 180 degrees in a clockwise direction.Hold the adjusting screw in this position and tighten the locknut (3) to a torque of 55 ± 10 N·m (41.0 ± 7.0 lb ft).To make an adjustment to the unit injectors on cylinders 1, 2, and 4, remove the timing bolt. Turn the flywheel by 360 degrees in the direction of the engine’s rotation. The engine rotates in a counterclockwise manner. This will put the number 1 piston at the top center position on the exhaust stroke.Repeat 2 through 4.Remove the timing bolt from the flywheel after all of the unit injector adjustments have been made. Reinstall the timing cover. Valves Table 6Engine Valve Lash SettingValvesValve Lash SettingInlet 0.38 ± 0.08 mm (0.015 ± 0.003 inch)Exhaust 0.64 ± 0.08 mm (0.025 ± 0.003 inch) Adjust the valve lash while the engine is stopped. Use the following procedure to adjust the valve lash:Put the No. 1 piston at the top center position. Refer to Testing and Adjusting, “Fuel System”. Note: If the engine is equipped with an engine compression brake, loosen the adjusting screw for the lash on the slave piston for the compression brake prior to adjusting the engine valve lash. Refer to the Testing and Adjusting, “Compression Brake” for information that relates to the adjustment of the slave piston lash for the engine compression brake.Before any adjustments are made, lightly tap the rocker arm at the top of the adjustment screw with a soft mallet. This will ensure that the lifter roller seats against the camshaft’s base circle. Note: Refer to Table 6 for the appropriate engine valve lash setting.Make an adjustment to the valve lash on the inlet valves for cylinders 1, 2, and 4.Loosen adjustment locknut (2) .Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.Tighten the adjustment locknut to a torque of 30 ± 7 N·m (22 ± 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut.Make an adjustment to the valve lash on the exhaust valves for cylinders 1, 3, and 5.Loosen adjustment locknut (2) .Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.Tighten the adjustment locknut to a torque of 30 ± 7 N·m (22 ± 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut.Remove the timing bolt and turn the flywheel by 360 degrees in the direction of engine rotation. This will put the No. 6 piston at the top center position on the compression stroke. Install the timing bolt in the flywheel.Before any adjustments are made, lightly tap the rocker arm at the top of the adjustment screw with a soft mallet. This will ensure that the lifter roller seats against the camshaft’s base circle.Make an adjustment to the valve lash on the inlet valves 3, 5, and 6.Lightly tap the rocker arm at the top of the adjustment screw with a soft mallet. This will ensure that the lifter roller seats against the camshaft’s base circle.Loosen the adjustment locknut.Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.Tighten the adjustment locknut to a torque of 30 ± 7 N·m (22 ± 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut.Make an adjustment to the valve lash on the exhaust valves for cylinders 2, 4, and 6.Loosen adjustment locknut (2) .Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.Tighten the adjustment locknut to a torque of 30 ± 7 N·m (22 ± 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut.Remove the timing bolt from the flywheel after all adjustments to the valve lash have been made. Reinstall the timing cover on the flywheel housing. heres the brake adjust Table 1Slave Piston Lash Setting Jake Brake Compression BrakesSerial Number PrefixSlave Piston Lash Setting3CS1-UP 2PN1-UP 8YS1-UP 0.64 ± 0.08 mm (0.025 ± 0.003 inch)CPD1-UP 9SM1-UP 2KS1-UP 9NS1-UP 1.02 ± 0.08 mm (0.040 ± 0.003 inch)1YN1-UP 1.14 ± 0.08 mm (0.045 ± 0.003 inch)MBJ1-UP MBL1-UP 1.40 ± 0.08 mm (0.055 ± 0.003 inch)Note: Slave piston lash is measured between the slave piston and the actuating pin that is on the exhaust valve bridge. Adjustments to the slave piston must be completed while the engine is stopped and the exhaust valves are closed. Use the following procedure to adjust the slave piston lash on cylinders 1, 3, and 5:Put No. 1 piston at the top center position on the compression stroke.Loosen adjustment locknut (1) .Place the appropriate feeler gauge between slave piston (2) and screw assembly (3). Turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the slave piston and the screw assembly. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.Tighten adjustment locknut (1) to a torque of 35 N·m (25 lb ft). Recheck the slave piston lash after tightening the locknut.Continue to check the slave piston lash for each of the cylinders that have been designated for adjustment. After each adjustment, tighten the locknut for the valve adjustment screw to a torque of 35 N·m (25 lb ft) and recheck the slave piston lash adjustment.Remove the timing bolt and turn the flywheel by 360 degrees in the direction of engine rotation. This will put No. 6 piston at the top center position on the compression stroke. Install the timing bolt in the flywheel. Follow steps 2 through 5 in order to adjust the slave piston lash on cylinders 2, 4, and 6.Remove the timing bolt from the flywheel after all adjustments have been made. Reinstall the timing cover on the flywheel housing. just take your time and watch what your doing. good luck

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