Models 316i, 318i produced before August 1993.
Note: Do not reinstall the removed toothed belt, and if it has been tensioned at least once, replace it, regardless of the mileage. A special BMW tool is required to properly tension the toothed belt.
Removal
Remove the radiator fan.
Disconnect all spark plug tips. You can use HAZET 1849 pliers for this.
Remove cover "1" from the ignition distributor. To do this, use a screwdriver to lift the upper and lower latches.
Lift up the cable channel "2". To do this, insert a screwdriver into the slots "arrow".
Unscrew the distributor cap (3 screws) and remove it together with the ignition wires.
Unscrew the distributor runner "4" and remove it together with the cover "3".
Remove the V-belt from the generator. To do this, unscrew bolt "1", unscrew the nuts of bolts "2" and "3". Turn bolt "3" in the direction of the arrow and thereby loosen the tension of the V-belt.
Loosen the water pump pulley. At the same time, squeeze the V-belt and thus hold the pulley from turning.
Unscrew the vibration damper "1" from the crankshaft. At the same time, engage 1st gear, tighten the handbrake, holding the belt pulley. Additionally, the parts shown in the figure:
1. Belt pulley
2. Bolt
3. Spacer washer
4. Central bolt
5. Timing belt pulley
6. Centering pin
7. Key
8. V-belt
Drain the coolant.
Unscrew the cooling system thermostat housing under the distributor (3 bolts "10") and put it aside. Remove the thermostat "6" with the gasket "7".
Unscrew 5 bolts "14" of the lower toothed belt casing. Remove the casing with the gasket. Unscrew 4 bolts of the upper toothed belt casing. Do not lose the centering bushings "16" for the upper bolts.
Turn the engine to the top dead center position of cylinder 1. In this case, the ignition distributor pin on the toothed pulley of the camshaft should be located at the bottom.
Fix the crankshaft in the top dead center position with the appropriate rod. To do this, insert the rod through the hole "arrow" in the engine block into the hole in the flywheel.
Loosen the camshaft toothed pulley mounting bolt without unscrewing it. A special key is required for this.
Loosen the tension roller nut "2", move the roller inward and thereby loosen the tension of the toothed belt. Additionally shown parts:
1. Timing pulley of the camshaft
3. Idler roller
4. Water pump
5. Oil pump
6. Oil pressure regulating valve
7. Timing mechanism housing cover
Remove the timing belt.
Caution: After removing the timing belt, do not disturb the top dead center position of the engine if possible.
Installation
Caution: When applying the timing belt, neither the camshaft nor the intermediate shaft should be out of position. Otherwise, severe engine damage may occur or the engine will not develop full power. After tensioning the timing belt, it is recommended to check the installation of the crankshaft and camshaft again.
Unscrew the cylinder head cover, remove the camshaft cover.
Check the position of the camshaft. At service stations, the camshaft is locked with device 113 11 90. The camshaft is in the top dead center position when the cams of cylinder 4 intersect. The cams intersect if they are facing upward symmetrically to the left and right relative to the edge of the cylinder head of an inclined engine.
Slightly tighten the camshaft toothed pulley bolts with a tightening torque of 1-3 Nm. Turn the camshaft pulley in the direction of engine rotation until it stops, with the protrusion entering the groove.
Slightly tighten the timing belt tension roller nut so that the tension roller can still move.
Place the timing belt on the camshaft timing pulley and then on the tension roller, pulling the belt from the crankshaft pulley.
Note: The toothed belt must be located in the middle of all pulleys.
Set the timing belt tension measuring device to "0".
Place the measuring device between the toothed pulleys of the crankshaft and camshaft so that both outer rollers are adjacent to the back of the toothed belt, and the middle finger is positioned between the belt teeth. See the operating instructions for the measuring device.
Move the tension roller to the left with the Allen key and thereby tension the toothed belt. Specified value when using the BMW measuring device 112080: 45-50 scale divisions.
Tighten the tension roller to a torque of 22 Nm.
Tighten the camshaft pulley to a torque of 60±5 Nm.
Caution: Remove the engine locking rod, camshaft locking tool and measuring instrument.
Turn the engine by the crankshaft pulley at least 2 turns (in the direction of engine rotation).
Again, fix the crankshaft and camshaft in the top dead center position as described above.
Loosen the camshaft timing pulley bolts again.
Install the BMW 112080 measuring device.
Loosen the tension roller fastening and briefly tighten the toothed belt to 45-50 divisions on the instrument scale.
After this, set the tension roller to the final value of 32±2 scale divisions.
Tighten the tension roller to a torque of 22 Nm.
Tighten the camshaft pulley to a torque of 60±5 Nm.
Caution: Remove the engine locking rod, camshaft locking tool and measuring instrument.
After tensioning the timing belt, it is recommended to check the position of the crankshaft and camshaft again.
Install the camshaft housing and cylinder head cover.
Screw on the upper timing belt cover, paying attention to the position of the centering bushings.
Screw on the lower timing belt cover, after checking the integrity of the gasket and replacing it if necessary.
Insert the thermostat into the housing, check the integrity of the sealing ring and replace if necessary.
Clean the contact surfaces, screw on the thermostat housing with a new gasket.
Fill with coolant, remove air from the cooling system.
Place the vibration damper on the crankshaft, aligning the damper hole exactly with the centering pin. Tighten the vibration damper fastening with a torque of 23 Nm.
Apply and tighten the V-belt.
Tighten nuts and bolts 1-3 in Fig. W 1056.
Install the camshaft sprocket cover, after checking the integrity of the cover sealing ring and replacing it if necessary.
Install the rotor and distributor cap. Installation is performed in the reverse order.
Insert the ignition wires into the guides.
Insert the cable channel into the cylinder head.
Install spark plug caps in the firing sequence of cylinders 1-3-4-2.
Insert the fan casing with the left and right bars into the mount. Insert the spacer clamps from the top left and right and secure them by hammering in the plastic pins.
Install the fan.
Attention: In the absence of adjustment and measuring devices (abroad, in case of an accident) temporarily tighten the toothed belt so that the belt can deflect by 5-10 mm in the area between the toothed pulley of the camshaft and the tension roller. At the earliest opportunity, the belt should be tensioned using a measuring device. Until then, avoid high engine speeds.
[The original text can be read on the website BMWMan.ru]