Caution! On engines with piston cooling oil jets, be careful not to damage the jets when removing the pistons. The manufacturer recommends adjusting the position of the jets using BMW 117 330 tools after removing and installing the pistons with connecting rods (m43TU engine) or 119,370 (n42 engine).
1. From a 4-cylinder engine, remove the cylinder head, oil pan and balance shaft housing as shown in chapter 2A.
2. For a 6-cylinder engine, remove the cylinder head, oil pan and oil pump as shown in chapter 2B.
3. Remove the oil separator (if there is one) from the bottom of the engine crankcase (Fig. 9.3).
4. If there is a protruding belt on top of the cylinder bores, indicating cylinder wear, it is recommended to remove it with a reamer or scraper to avoid damaging the pistons during disassembly.
5. Check whether the connecting rods and lower head caps are marked. Both the connecting rods and lower head caps should be numbered, starting from the front end, i.e. from the camshaft drive chain. If there is no such marking, apply it yourself with digital stamps or a center punch on the machined surfaces of the connecting rods and lower heads (Fig. 9.5).
6. Turn the crankshaft so that pistons No.1 and 4 (4-cylinder engine) or 1 and 6 (6-cylinder engine) reached bottom dead center (BDC).
7. Unscrew the bolts securing the lower head cover of connecting rod N5 1. Remove the cover and take out the lower bearing shell (Fig. 9.7). If the bearing shells are not to be replaced, tie the shell to the cover.
8. Using the hammer handle, push the piston up and pull it out from the top of the cylinder. Remove the upper bearing from the connecting rod and tie it to the connecting rod. Be careful when doing this - do not damage the oil nozzle in the cylinder.
9. Screw the lower head cover onto the connecting rod to store them as a set.
10. In the same way, remove the piston with the connecting rod from the 4th (or from the 6th) cylinder.
11. Turn the crankshaft so that the remaining pistons are in BDC one by one, and remove the pistons with connecting rods in the same way.
(The original text can be read on the website «BMWMan.ru»)