Withdrawal
Release models prior to August 1993 (M40 engine): Remove the toothed belt and unscrew the camshaft sprocket.
Detach crankcase breather hose -6- from cylinder head cover.
Unscrew cylinder head cover and remove with gasket -1- and trim -3-.
Release models since September 1993 (M43 engine): Crank the engine at the crankshaft pulley until one of the camshaft cams above the rocker arm points upwards. Install the BMW tool in this position and press the valve. Sequentially remove the rocker arms and fold them in the order of subsequent installation.
Release models since September 1993 (M43 engine): Remove the cylinder identification sensor from the gear box cover. With the engine at cylinder 1 top dead center, unscrew the camshaft drive chain sprocket.
Remove bolts -1- and -2- and remove oil line. Attention: Mark the position of the gaskets of the bolt -2- for subsequent installation.
Remove 4 bearing caps and also bearing -F-. Fold the bearing caps in the order of subsequent installation
Pull out the camshaft.
Remove the old camshaft seal.
Installation
Lubricate the camshaft bearings with engine oil and insert the camshaft.
Release models prior to August 1993 (M40 engine): Coat the surface of the bearing cap -F- at the marked points (see photo) a thin layer of non-thickening sealant, such as Curil.
Reinstall all bearing caps and tighten bolts evenly to 15 Nm. On pre-August 1993 models (M40 engine) make sure that the centering sleeves -7- are fitted on the first bearing cap.
Insert oil line -14-. Always renew gaskets -16- for central hollow bolt -15-. Tighten bolts -17- to 6 Nm and bolts -15- to 11 Nm.
Release models prior to August 1993 (M40 engine): Lubricate new oil seal -13- with engine oil and push it as far as possible with a piece of pipe of the correct diameter. After that, carefully press it in until it stops. At BMW workshops, press-in sleeve 331190 is used for this.
If required, measure the camshaft play. Specified values of axial play: 0.15 0.33 mm; radial play. 0.02 0.54 mm: jaw height 34.83 34.95 mm.
Put the casing on the camshaft, install the cylinder head cover with gasket and tighten the bolts to a torque of 10 Nm. Replace damaged gasket.
Connect the crankcase ventilation hose.
Release models prior to August 1993 (M40 engine): Install toothed belt.
Release models since September 1993 (M43 engine): Install sprocket with chain applied. The arrow on the chain sprocket should point up. Align the slots in the middle. Tighten the 4 sprocket mounting bolts to 10 Nm. Install the cylinder identification sensor. Caution: Remove the crankshaft and camshaft retainers.
Release models since September 1993 (M43 engine): Crank the engine at the crankshaft pulley until one of the camshaft cams above the rocker arm points upwards. Install the BMW tool in this position and press the valve. Install the rocker arms in their original places.
Install the cylinder head cover and connect all connections on the engine.
Start the engine at idle speed. If the rockers knock (unusual engine noises), do not let the engine run at speeds above 2000 rpm until the knocking stops. In this case, the hydraulic compensators are filled with oil and automatically set the required valve clearances.
Attention: Keep the removed valve clearance compensators upside down for no more than 10 minutes, as the oil filling slowly flows out and the compensator becomes inoperative.