If measurements are required on the camshafts. Specified values of axial play: 0.15 - 0.33 mm; radial play: 0.02 - 0.061 mm.
Withdrawal
Remove cylinder head.
Camshaft removal requires BMW tool 113260 (318is: 113270). It is designed to hold all of the camshaft bearings in position when the bearing caps are removed. The instructions for the work steps apply to both camshafts, the order of removal is irrelevant.
Remove spark plugs.
Install the fixture and screw it into the threaded holes of the spark plugs with a tightening torque of 25 Nm.
By turning the shaft with the eccentrics of the tool, press the bearing caps. The figure shows a six-cylinder engine.
Loosen all bearing cap screws.
Remove fixture.
Remove bearing caps and camshaft. Bearing caps are marked from A1 to A7 (3181 to A5) for exhaust camshaft and E1 to E7 (3181 to E5) for the intake camshaft. When installing, the covers must be installed in their original places.
If required, such as when valves are to be removed, remove the bearing bracket assembly with the valve lifters.
Caution: If the valve lifters are not secured, they will fall out of the bearing bracket. At BMW workshops, a suction cup is used to fix the tappets, which is put on the pusher from above. When removing the pushers from the bearing strip, they must subsequently be installed in their original places.
Attention: Keep the removed valve tappets upside down for no more than 10 minutes, as the oil filling slowly flows out and the compensator becomes inoperative.
Installation
Attention: When the camshaft is removed, the following must be observed: Without load from the camshaft, the hydraulic valve lifters expand and after installation they take some time to return to their original size. Because of this, the valves may be open longer than determined by the camshaft adjustment, and sit on the pistons. Therefore, a pause must be maintained between the installation of the camshaft and the installation of the cylinder head: At +20°C (room temperature): 4 minutes; at +10°C: 11 minutes. After installing the cylinder head, wait another 30 minutes before starting the engine.
If the camshaft was removed with the cylinder head removed, turn the crankshaft at the hexagon of the belt pulley in the direction of engine rotation (right) approximately 30°past top dead center. As a result, none of the pistons takes its upper position and the valves do not sit on the pistons. Insert the camshaft and observe the intervals indicated. Only then return the crankshaft to top dead center and install the chain, see section "Removal and installation of a head of cylinders".
Check valve lifters for wear (scratches) and, if required, replace.
Lubricate the camshaft bearings with engine oil and insert the camshafts as shown. so that the intake and exhaust valves of cylinder 1 are directed towards each other.
Note: The difference between the intake camshaft and the exhaust camshaft is: The sprocket flange on the exhaust camshaft has a recess. In addition, there are 2 embossed letters between the flange and the 1st cam. 1st letter: A = exhaust camshaft, E = intake camshaft; 2nd letter: A = 3251 engine until August 1992, D = 3251 from September 1992
Make sure that there are centering sleeves -3- on the bearing studs 2 and 7 (318is: 2 and 5).
Install the bearing bracket with the valve lifters inserted into the cylinder head. The bearing plate of the exhaust camshaft is marked -4- "A", and the intake camshaft bearing bar is marked "E".
Put the bearing shells in accordance with their marking, the covers must be in their original places.
Position tool and press bearing shells.
Tighten the bearing shells to 15 Nm.
Unload and remove the fixture, screw in the spark plugs.
Install the cylinder head.