Camshaft: Service and Repair
Removal/Installation
Overview
- Set piston of No. 1 cylinder to 45° before ignition TDC (arrow), refer to step 1 below).
- Remove upper front covers (10 and 12). Service and Repair
- Mark camshaft timing gears relative to timing chain, refer to step 3 below.
- Remove chain tensioner (13), install. Service and Repair
- Remove top slide rails (1, 1a, 2, 2a), install. Service and Repair
- Mark camshaft bearing caps (14), refer to step 6 below.
- Turn camshafts (5), (6), (7) and (8) in direction of arrow with wrench special tool 119 589 00 01 00 (slacken), refer to step 7 below.
- Unscrew camshaft bearing caps (14), take off, refer to steps 8 and 9 below.
Tighten to: 10 Nm
- Using special tool 119 589 00 05 00, take off camshafts with camshaft adjuster and camshaft timing gear, install, refer to steps 9 to 20 below.
CAUTION Since 1993 the camshaft bearing caps are no longer fixed in position with dowel sleeves but the bearing caps are centered by means of the bearing points of the camshafts when the securing bolts are tightened to specification.
- Check basic setting of camshafts. Testing and Inspection
NOTE:
- The camshaft bearing caps are numbered consecutively (arrows), beginning at the right exhaust camshaft at the front.
- The numbers (arrows) are cast in the cylinder heads.
- The camshaft bearing caps must be re-installed at the same point.
CAUTION:
- The camshafts are sensitive to fracturing and must not be twisted when removing and installing camshaft bearing caps.
- If a camshaft is removed, all the others must be secured with fixing pins to prevent them turning.
Procedures
1. Set piston of No. 1 cylinder to 45° before TDC (arrow).
2. Remove upper front cover at top. Service and Repair
3. Mark position of camshaft timing gears (arrows) relative to timing chain.
NOTE: If the camshaft timing gear is removed, the colour marking must be transferred to the corresponding point on the new camshaft timing gear.
4. Remove and install chain tensioner. Service and Repair
5. Remove top slide rails. Service and Repair
6. Lift timing chain off camshaft sprockets.
Rotate camshafts with wrench 119 589 00 0100 so that only the base circle of the cams is touching the bucket tappets in each case.
NOTE: The timing chain is secured on the camshaft sprocket to prevent it turning when the timing case cover is installed.
Removal Note
- Rotate camshafts free of tension: rotate right exhaust camshaft and right inlet camshaft approx. 6 teeth in direction of rotation of engine.
- Rotate left inlet camshaft approx. 10 teeth in opposite direction of rotation of engine.
- Rotate left exhaust camshaft approx. 14 teeth in direction of rotation of engine.
7. Slacken camshaft bearing caps alternately so as to prevent any one-sided residual stress acting on the camshaft.
8.. Take off camshaft bearing caps and camshafts together with camshaft sprockets and camshaft adjusters.
Installation
9. Oil bucket tappets and camshaft bearing points.
10. Insert left inlet and exhaust camshafts with timing chain fitted, free of tension.
Pay attention to guide bearing at bearing point 3.
11. Oil bearing caps, install and tighten uniformly to 10 Nm.
Camshaft must not be over-tensioned on the one side.
Part 1 Of 2:
Part 2 Of 2:
12. Rotate camshaft with wrench (3) 119 589 00 0100 and check for ease of movement.
13. Rotate left exhaust camshaft into position with wrench (3).
Fit timing chain onto the marking affixed previously to the exhaust camshaft sprocket and pin with pin (1), special tool 111 589 03 15 00.
14. Rotate left inlet camshaft into position with wrench (3).
Fit timing chain onto the previously affixed marking on the inlet camshaft sprocket and secure with pin (1).
Camshafts in "retarded" position (arrow).
15. Insert right inlet and exhaust camshafts free of tension, with timing chain fitted.
Pay attention to guide bearing at bearing point 3.
16. Oil bearing caps, install and tighten uniformly to 12 Nm.
Camshaft must not be over-tensioned on the one side.
17. Rotate camshafts and check for ease of movement.
18. Rotate right inlet camshaft into position with wrench 119 589 00 01 00.
Fit timing chain onto the marking affixed previously to the intake camshaft sprocket and pin with pin 111 589 03 16 00.
Camshafts in "retarded" position (arrow).
19. Rotate right exhaust camshaft into position with wrench 119 589 00 01 00.
Fit timing chain onto the marking affixed previously to the exhaust camshaft sprocket and pin with pin 111 589 03 15 00.
20. Install in reverse order, beginning with step 5.
21. Check basic setting.