For engines with the letter designation BBM
Removal the camshaft timing sprocket
Lock the camshaft and crankshaft at TDC of the 1st cylinder. Remove the timing gear cover. Lock the camshaft drive chain tensioner. The camshaft drive chain tensioner with rubber stop must be removed. After removing the camshaft screw, remove the camshaft chain sprocket. Screw on the crankshaft screw with the sleeve and crankshaft pulley. Tightening torque: 90 Nm + additional rotation + 45° (1/8 turn). After removing the lock bolt, turn the crankshaft 45° against the direction of rotation of the engine shaft. In this condition, it is possible to carry out repair work on the valve timing mechanism.
Installing the camshaft chain sprocket, adjusting the timing
Neither piston should be at TDC.
Important: To turn the camshaft with the chain sprocket removed, tighten the screw with 2 washers with a maximum torque of 20 Nm + 45°(1/8 turn) into the camshaft and turn the camshaft. The pistons must not be at TDC. Whenever the camshaft is removed, the camshaft center screw must be replaced. The lock bolt must not be used as a counter support for loosening and tightening the camshaft bolts. The engine may be easier to turn if the spark plugs are removed.
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After adjusting the distributor to TDC of the 1st cylinder, lock it. It is not possible to turn the camshaft in any direction after locking. Unscrew the camshaft screw. Remove oil residue from the journal (trunnion) of the camshaft and the camshaft timing sprocket at the contact point using a clean cloth. Place the camshaft timing sprocket with the attached timing chain onto the camshaft, then screw in a new camshaft bolt so that the camshaft timing sprocket can still be turned slightly. Install the tensioner with the rubber stop. Tighten the camshaft drive chain. Turn the crankshaft 45° in the direction of rotation of the engine shaft to TDC of the 1st cylinder and lock it.
Important: If the crankshaft is turned through the TDC of the 1st cylinder (follow the mark on the flywheel), you should turn the crankshaft back again and adjust the TDC of the 1st cylinder again. Otherwise, as a result of further rotation of the crankshaft, the piston will hit the valves.
Turn the camshaft chain drive sprocket "1" using a counter support to lock the camshaft drive gear against the direction of rotation of the engine shaft "arrow" until it stops and, holding the camshaft chain drive sprocket in this position, tighten screw "2".
Tightening torque: 20 Nm + turn an additional 90° (1/4 turn). Crank the engine carefully at least 2 revolutions to ensure that none of the valves will sit on the piston crown when the engine is started and check the timing again. The rest of the installation is carried out in the reverse order of actions. Check the position of the camshaft in relation to the crankshaft.
For engines with the letter designation BZG
Removal the camshaft timing chain sprockets
Lock the camshafts and crankshaft at TDC of the 1st cylinder. Remove the timing gear cover. Lock the camshaft drive chain tensioner. The camshaft drive chain tensioner with rubber stop must be removed. After removing the camshaft bolts, remove the camshaft timing chain sprockets. Screw on the crankshaft screw with the sleeve and crankshaft pulley. Tightening torque: 90 Nm + additionally turn by +45° (1/8 turn). After removing the lock bolt, turn the crankshaft 45° against the direction of rotation of the engine shaft. In this condition, it is possible to carry out repair work on the valve timing mechanism.
Installing camshaft chain sprockets, adjusting timing
Neither piston should be at TDC.
Important: To turn the camshaft with the chain sprocket removed, tighten the screw with 2 washers with a maximum torque of 50 Nm + 45° (1/8 turn) into the camshaft and turn the camshaft. The pistons must not be at TDC. The T10 123 locking device must not be used as a counterhold for loosening and tightening the camshaft screws. The engine may be easier to turn if the spark plugs are removed.
After adjusting the camshafts to TDC of the 1st cylinder, lock them. Unscrew the camshaft screw. Remove oil residue from the journals (trunnions) of the camshafts and the camshaft timing sprockets at the contact point using a clean cloth. After placing the camshaft chain drive sprockets with the camshaft drive chain on the camshafts, screw in the new camshaft bolts in such a way that it is still possible to turn the camshaft chain drive sprockets a little. Install the tensioner with the rubber stop. Tighten the camshaft drive chain. Turn the crankshaft again by 45° in the direction of rotation of the engine shaft to TDC of the 1st cylinder and lock it.
Important: If the crankshaft is turned through the TDC of the 1st cylinder (follow the mark on the flywheel), you should turn the crankshaft back again and adjust the TDC of the 1st cylinder again. Otherwise, as a result of further rotation of the crankshaft, the piston will hit the valves.
Tighten screw "2" of camshaft drive gears "1" with 50 Nm (use a lever to lock the camshaft drive gear). Finally turn the screws 90° (1/4 turn) with a hard key.
Tightening torque: 50 Nm + turn an additional 90° (1/4 turn). Crank the engine carefully for at least 2 revolutions to ensure that none of the valves will sit on the piston crown when the engine starts and check the timing again. The rest of the installation is carried out in the reverse order of actions. Check the position of the camshaft in relation to the crankshaft.
Removal and installation the sealing ring (oil seal) and flywheel
1 - 90 Nm + turn an additional 90° (1/4 turn); 2 - Crankshaft pulley; 3 - Bushing, install on cleaned crankshaft; 4 - O-ring, replaces the sleeve seal with silicone mastic; 5 - Sealing ring, for the crankshaft on the pulley side, do not lubricate the working edge of the sealing ring with either grease or oil, before installing, remove any remaining grease on the bushing with a clean cloth; 6 - Cylinder block; 7 - 60 Nm + turn an additional 90° (1/4 turn), tighten in two stages: stage I = 60 Nm stage II = 90° (1/4 turn); 8 - Flywheel, installation is possible only in one single position "mutually offset holes"; 9 - Intermediate sheet, must be installed on centering bushings; 10 - Sealing ring, for the crankshaft on the flywheel side, do not lubricate the working edge of the sealing ring with either grease or oil, before installation, remove any remaining grease from the camshaft journals with a clean cloth