M43TU engine
Note. The manufacturer recommends that before removing the camshafts, compress the valve springs to release the pressure from the camshafts. This operation requires a special tool. However, if you take precautions and unscrew the nuts of the shaft bearing caps gradually and evenly, then you can do without a device. This is the method described below in this paragraph. When assembling, you will need new seals for the oil pipe mounting screws.
Withdrawal
1. Remove the cylinder head cover (see paragraph 4).
2. Turn the crankshaft to the TDC position of piston No. 1, but do not fix the crankshaft and camshafts in this position.
3. Turn the crankshaft one more turn in a clockwise direction so that the No. 4 piston is at TDC at the end of the compression stroke. Turn out two available bolts of fastening of an asterisk of a camshaft.
4. Again turn the crankshaft one revolution clockwise to return the No. 1 piston to the TDC position again. Fix the crankshaft and camshaft with tools (see paragraph 3).
5. Turn out the remained two bolts of fastening of an asterisk to a camshaft. Remove the shaft position sensor rotor from the sprocket.
6. Pull back the upper end of the tensioner shoe so that the chain is loosened and the sprocket can be removed. Remove the sprocket and disconnect the chain from it. Do not let go of the chain so that it does not fall into the lower part of the case. Tie the chain with wire somewhere at the top.
7. Turn out bolts of fastening of a tube of a supply of lubrication to covers of shaft supports (pic. 11.7). Remove the seals from the bolts.
8. Check if there are markings on the support covers. The first cover should not be marked, but the rest should be numbered from 2 to 5, starting from the side of the chain (pic. 11.8). If there is no marking, apply it yourself.
9. Gradually evenly unscrew the nuts securing the covers of the shaft supports and remove the covers.
10. Lift the shaft from the supports and remove it from the cylinder head.
11. Prepare a box with sections filled with oil. It will be necessary to fold the hydraulic rocker supports into it as they are removed, so that they are stored in the order of their previous installation.
12. Remove the rocker arms, valve thrust pads and lay them out so that they can be installed in their original places during assembly (pic. 11.12.a, b).
13. Remove the hydraulic rocker arms and place them in boxes filled with oil (pic. 11.13.a, b).
Inspection
14. Wash all parts, borings for bearings in the cylinder head and covers. Carefully inspect the parts for wear and damage. Pay special attention to the condition of the surfaces of the cams and bearings. Inspect the rocker arms for wear and damage. Replace defective parts.
Installation
15 Lubricate the hydraulic bearing bores in the cylinder head and insert the bearings into their original positions.
16. Put persistent linings on cores of valves, establish yokes on former places.
17. Lubricate the bores of the shaft supports in the cylinder head and lower the shaft into them so that both valves of cylinder No. 1 are closed, and the valves of cylinder No. 4 are in the transition position (exhaust valve closes and intake valve opens). To check, look at the square flange at the end of the shaft - its flat edges should be perpendicular to the top plane of the cylinder head (perpendicularity can be checked with a square). Additionally, the position of the camshaft can be checked with a template (see paragraph 3).
18. Lubricate the working surfaces of the bearing caps.
19. Install covers as marked. Screw on the nuts for fastening the covers and tighten them gradually in turn to the required torque.
20. Replace the seals on the grease tube mounting bolts, then install the tube and tighten the bolts.
21. Remove the upper side of the tensioner shoe from the chain and loosen the chain enough to allow the sprocket to be mounted on the camshaft. Engage the sprocket with the chain so that the arrow on the sprocket is pointing up.
22. Fix the camshaft with a template (see paragraph 3). Slide the sprocket onto the shaft so that the bolt holes in the shaft flange align with the centers of the oblong holes in the sprocket. Install the encoder rotor onto the sprocket with the arrow on the rotor pointing up (pic. 11.22). Install the top two sprocket mounting bolts and hand-tighten as far as possible.
23. Release the tensioner shoe and tighten the two available sprocket mounting bolts to the required torque.
24. Remove the flywheel retainer and template for checking the position of the camshaft.
25. Rotate the crankshaft one full turn clockwise so that the No. 4 piston is at TDC at the end of the compression stroke. In this position, screw in and tighten the two remaining sprocket mounting bolts.
26. Install the cylinder head cover (see paragraph 4).
N42 engine
Removing the intake shaft
Note. Removing the shaft will require a few genuine BMW tools.
27. Set the engine to the TDC position of the piston N51, as indicated in paragraph 3.
28. Having fixed the camshafts, as indicated in paragraph 3, loosen the bolts securing the valve timing adjustment units on both camshafts (see fig. 7.28).
29. On the front right side of the cylinder block, unscrew the tensioner plunger assembly (see fig. 7.29). Be prepared for oil to come out of the hole. The sealing washer under the assembly head will need to be replaced with a new one during assembly. If the assembly is to be used further, stand it upright and push the plunger to force any remaining oil out of the assembly.
30. Completely turn out a bolt of fastening of a regulator of phases of an exhaust shaft and remove a regulator together with an asterisk and a shaft position sensor rotor. Do the same for the intake shaft. Pay attention to that. that regulators are marked IN (inlet) and EX (high school graduation). Do not mix up regulators when assembling (pic. 11.30). When removing the sprocket, do not let go of the chain so that it does not fall into the bottom of the crankcase. Tie a chain up somewhere.
31. Remove the eccentric shaft motor as described in paragraph 10.
32. Disconnect the shaft position sensor electrical connector on the front side of the chain cover by squeezing the protrusions of the connector plug.
33. Remove the plug behind the intake shaft position sensor and unscrew the chain guide pin (see fig. 7.33).
34. Remove the chain guide bolt, carefully pry the top end of the left guide and release the bottom end of the top guide. Remove the upper damper from the engine (pic. 11.34, a, b).
35. Turn out a bolt of the union of a tube of a supply of oil to a final camshaft and take a tube back about 20 mm.
36. Remove the camshaft fixing templates.
37. Turn the eccentric shaft with a hexagon wrench so that, if possible, weaken the spring at the rear end of the shaft (pic. 11.37).
38. Using a wire tie or something similar, pull the end of the spring up and back to free it from the lever and from the shaft (pic. 11.38).
39. Turn the eccentric shaft to the position of the minimum stroke of the valves (pic. 11.39).
40. Install special tool 11 9 302 on the end of the intake shaft and secure it with tool 11 9 303 (pic. 11.40). Thus, the shaft is fixed on the support.
41. Attach the eccentric shaft to the rear end of the camshaft with tool 119 301 (pic. 11.41). Tighten the tool screw by hand to prevent the camshaft from rotating.
42. Attach special tools 11 9 310 to the oil supply pipe and to the undersides of the intermediate levers of the valve mechanism to prevent the levers from moving (pic. 11.42).
43. The shaft support is fixed with 13 nuts. Gradually and evenly unscrew the nuts and remove the support (pic. 11.43).
44. Before removing the camshaft, it is necessary to relieve the pressure of the springs of the intermediate levers. For this, special tools 11 9 390 and 11 9 320 are used as follows. Clamp special tool 11 9 320 in a vice. Turn over the shaft support and install it on the tool (pic. 11.44).
45. Remove the sealing tubes of the candles from the support. Discard the tube o-rings - new ones will be required during installation.
46. Install special tool 11 9 390 over the camshaft between the two halves of the N5 cylinder spring 4. Fix the tool with the bolt supplied with it (pic. 11.46, a, b).
47. Fasten the fixture so that its holder is located on top of the spring mounting plate. Squeeze the jaws of the device. Remove the plate fixing screw and slowly release the jaws, releasing the spring (pic. 11.47, a, b).
Attention! Do not attempt to deflate the springs without the specified tool. The springs are tight and can cause injury.
48. Remove the spring along with the plate.
49. Remove the fixture and repeat the procedure on the remaining springs.
50. Remove the tools that secure the intermediate levers to the grease supply tube. Remove intermediate levers and store them in a specific order. When installed, they should return to their original position.
51. Remove the tools from both ends of the camshaft. Remove the camshaft.
52. If necessary, remove the rocker arms and hydraulic inlet valve supports. Keep the rocker arms in a certain order - when assembling, they should return to their original position. Disconnect the rocker arms from the hydraulic supports. During assembly, the supports must also be installed in their original places. Keep bearings immersed in engine oil.
53. If necessary, you can remove the spring rings at the ends of the shafts. To do this, press one end of the ring 8 into the groove, and pull the ring out by the other end (pic. 11.53). Be careful - the rings are fragile and easy to break.
Intake shaft inspection
54. Wash all parts, as well as the working surfaces of the bearings and shaft covers. Inspect parts for wear and damage. Pay special attention to the surfaces of the supports and cams. Examine surfaces of yokes and intermediate levers. Replace severely worn or damaged parts.
Installing the intake shaft
55. Turn the shaft support over and place it on special tool 11 9 320, clamped in a vise. Lubricate the working surfaces of the shaft bearings with engine oil.
56. Lay the intake shaft in the supports. Turn the shaft so that the rounding at its rear end points downwards (pic. 11.56).
57. Expand the spring rings on the front end of the shaft with the gap up (see fig. 11.53).
58. Install tools 119 302 and 11 9 303 on the front end of the shaft, and tool 11 9 301 on the rear end. Installing these tools fixes the shaft on the support and on the eccentric shaft. Check if the eccentric shaft is installed correctly.
59. Lubricate the running surfaces of the intermediate levers, then insert them into place between the camshafts and eccentric shafts (pic. 11.59, a, b).
60. Fasten the intermediate levers with special tools 11 9 310 to the lubrication tube.
61. As with disassembly, install special tool 11 9 390 in the gap where the intermediate lever springs are to be inserted. Start at the rear end of the shaft. Insert the spring so that the spring retaining plate is in the holder of the tool (rice, 11.61).
62. Gently compress the jaws of the fixture and secure the spring mounting plate with the screw. Tighten the screw securely. Repeat these steps for the rest of the springs.
63. Put new o-rings on the candle tubes (the ring of smaller diameter is installed on the lower end of the tube, see fig. 4.25). Lubricate the rings with clean engine oil and insert the tubes into the cylinder head.
64. Install the intake rocker arms (if they were removed) to their original places.
65. Establish a support with shafts on a head of cylinders and fix 13 nuts by hand.
66. In sequence from inside to outside, tighten the nuts of the shaft support, first to 5 Nm, then in the same sequence to 10 Nm. If the eccentric shaft was previously removed, now is the time to finally tighten the covers of its supports to the required torque.
67. Remove the devices that fix the intermediate levers on the tube and fix the camshaft. Replace the oil supply tube to the outlet shaft, screw in and tighten the tube fitting bolt.
68. Using the hexagon wrench, turn the eccentric shaft so that it is possible to install a spring on its rear end. Turn the shaft to achieve maximum spring force.
69. Install the tools that fix the camshafts in the TDC position of the piston No. 1.
70. The rest of the installation is carried out in the reverse order of removal.
Removing the exhaust shaft
71. Remove the support with the shafts, as indicated in p.p. 27-43 of this paragraph.
72. Turn out three bolts and remove the vacuum pump from the back end of an exhaust shaft (see chapter 9). The o-ring can be discarded - a new one will be required during installation.
73. Pull out the lubricant supply pipe to the outlet shaft from the clamps on the bearing covers.
74. Gradually and evenly unscrew the nuts of the exhaust shaft bearing caps. Pay attention to the marking of the covers: they must be numbered A1, A2, AZ and A4 from the side of the intake shaft. The numbering starts from the side of the chain. Remove covers.
75. Raise the exhaust shaft from the supports. If necessary, remove the spring rings from the end of the shaft, as described in step 53. Be careful - the rings break easily.
76. If required, remove the exhaust valve rockers along with the hydraulic bearings. Separate the supports from the rocker arms. Store them like this. so that when assembled they take their former places. Keep hydraulic mounts immersed in engine oil.
Exhaust shaft inspection
77. See par. 54.
Installing the exhaust shaft
78. Lubricate the working surfaces of the shaft bearings with engine oil.
79. Install exhaust valve rockers (if they were removed).
80. Support the shaft and rotate it so that the rounding on the rear end of the shaft is facing up (pic. 11.80).
81. Turn the rings on the front end of the shaft with the gaps up (pic. 11.81).
82. Lubricate the shaft bearing covers with engine oil and install the covers in place, taking into account the markings.
83. Install oil feed tube clamps on covers #1 and #4. Install the cap nuts and tighten them evenly and gradually until the bottom surfaces of the caps touch the cylinder head.
84. In sequence from the inside out, tighten the cap nuts half a turn at a time until the correct torque is reached.
85. Clamp the lubrication tube and slide the tube about 20 mm back.
86. Reinstall the vacuum pump, aligning the shank of the pump shaft with the slot on the end of the camshaft (pic. 11.86).
87. The rest of the installation is carried out in the reverse order of removal.