Removing Camshafts

→ Absolute cleanliness is essential when working on the engine.

→ Lay removed engine parts on a clean base and make sure to cover them.

→ Use the cover for dust protection when fitting the engine NR.165  on the engine assembly support.

1. Check engine position. The first cylinder on the cylinder side to be removed (viewed from the belt side) must be in the overlapping TDC position.
   1. 1.1. To do this, turn the engine clockwise at the crankshaft pulley until the correct camshaft position is reached.
   2. 1.2. Position of cylinder bank 1-3: the cams on the intake and outlet camshaft of cylinder 1 are facing each other.
      Fig 1: Overlapping TDC Of Cylinder 1

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   3. 1.3. Position of cylinder bank 4-6: the cams on the intake and outlet camshaft of cylinder 4 point away from each other (each points towards the cylinder head outer wall).
      Fig 2: Overlapping TDC Of Cylinder 4

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      • -1 - Outlet camshaft
      • -2 - Intake camshaft
2. Remove chain tensioner (observe the marking).
   1. 2.1. Unscrew two M6 x 20 Torx screws on chain tensioner cover and remove cover. Then remove the chain tensioner.
      Fig 3: Identifying Chain Tensioner

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3. Remove guide rail for timing chain.
   1. 3.1. Unscrew three Torx screws (M6 x 25) on the guide rail and remove the rail.
      Fig 4: Locating Guide Rail Screws

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   Information 

   When loosening or tightening sprockets and camshaft adjustment elements, a second person must counter with the appropriate holding wrench.

4. Loosen outlet sprocket. The timing chain must not be under too much strain during this procedure.
   1. 4.1. Loosen M12 cheese head bolt, internal serration -2-  ; to do this, counter at the sprocket with the special tool Holding Wrench 9653/1  .
   2. 4.2. Mark the driver for the cylinder side to avoid problems during installation (different height).
      Fig 5: Identifying Sprocket And Actuator Bolts

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5. Loosen camshaft adjuster on the intake camshaft. The timing chain must not be under too much strain during this procedure.
   1. 5.1. Loosen M12 x 130 central screw by countering at the hexagon piece with a ring wrench (a/f 30) -2-  .
      Fig 6: Loosening/Tightening Camshaft Actuator

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   Information 

   • Only remove oil guide housing from the camshaft if the camshaft has to be replaced. 
   • Use a magnetic socket-wrench insert when unscrewing the cylinder screws. 
   • The oil guide housings of cylinders 1 - 3 and 4 - 6 differ in height. 
     Fig 7: Identifying Oil Guide Housings

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6. Loosen oil guide housing (do not remove it).
   1. 6.1. Heat the three hexagon socket head bolts (M5 x 10, micro-self-locking) with a hot-air gun and screw out bolts.
      Fig 8: Locating Oil Guide Housing Bolts

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7. Remove camshaft housing.
   1. 7.1. Loosen the Torx screws (M6 x 30) on the housings evenly from the inside out. Remove the housings in the specified order.
      Fig 9: Locating Camshaft Housings

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   2. 7.2. Lift up the camshaft housings. The housings must not be confused (note the marking).
      Fig 10: Lifting Up Housings

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8. Remove thrust bearing cover.
   1. 8.1. Unscrew six Torx screws (M6 x 30) and lift the thrust bearing cover up and off (note the marking).
      Fig 11: Locating Thrust Bearing Cover Screws

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9. Lift camshafts out.
   1. 9.1. Assign camshafts by cylinder bank (e.g. mark with a paint marker) and place them on a clean surface.

   Camshaft assignment: 

   • Cylinder bank 1-3: outlet camshaft with lubrication bore for tandem pump and long intake camshaft.
   • Cylinder bank 4-6: outlet camshaft without bore and short intake camshaft.
10. If necessary, remove exhaust bucket tappets and intake switching tappets and check them for visible wear.
    1. 10.1. If you remove them, have a clean surface prepared on which you can write details of each one. Note the installation position of the bucket tappets in the housing. → Example of laying aside bucket tappets 
       Fig 12: Noting Installation Position Of Bucket Tappets

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