• If the wear limit, distance “ B ”, is exceeded, first inspect the tensioner rail and the two guide rails for score-marks and replace them if necessary. • If a part has to be replaced, repeat the measure- ment procedure described above. If the wear limit has been exceeded, the timing chain must be replaced. 11 34 020 Removing valves • Use suction cup, BMW No. 11 3 251 , to pull out the bucket-type tappets. • Check that bucket tappets and guides are in per- fect condition. Bore for bucket tappet In cylinder head...............max. 33.600 mm (1.32 in) Radial clearance, bucket tappets..........................max. 0.200 mm (0.008 in) Distance “ B ”......................max.
9.0 mm (0.0354 in) e Attention: The bucket tappets must be reinstalled in their orig- inal bores, so it is important to mark them accord- ingly (risk of jamming). 11 12 528 Disassembling and assem- bling cylinder head 6 5 4 E110130 3 2 L Note: To simplify removal of the valve collets, tap the valves sharply with a plastic-faced hammer. • Secure the cylinder head to support plate, BMW No. 11 0 523 . • Secure adapter plate, BMW No. 11 0 521 , support, BMW No. 11 5 691 , spindle, BMW No. 11 5 692 , nut, BMW No. 11 5 693 , and thrust plate, BMW No. 11 0 522 . 1 E110120 L Note: When removing the exhaust valves, slip suitable washers (approx.
5 mm (0.2 in) thick) between thrust spindle and thrust plate and dispense with the nut for securing the thrust plate to the thrust spindle. 1. Valve 2. Lower valve retainer 3. Valve stem seal 4. Valve spring 5. Upper valve retainer 6. Valve collets • Press down the valves with the thrust plate. • Use a screwdriver to press apart and remove the valve collets. • Pull the valves down to remove. 11.29 5 691 11 1 1 3 11 0 52 11 0 52 11 0 52 11 5 691 5 692 11 5 692 1 0 522