Installing Camshafts - Cylinders 4-6

→ 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.

Designation of housings of camshafts: 

Fig 1: Locating Camshaft Housing Designation

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Inlet camshaft: 

• Thrust bearing:  'E' and matching number on cylinder head/cylinder head cover
• Housing of bearing sleeve:  only matching number

Outlet camshaft: 

• Thrust bearing on sprocket:  '1A' and matching number on cylinder head/cylinder head cover
• 2nd thrust bearing:  '2A' and matching number on cylinder head/cylinder head cover

Information 

• The engine must be always turned clockwise (running direction of engine) during assembly work on the timing drive mechanism. 
• Only turn engine using the crankshaft pulley, not at the camshafts. 

1. To remove the play from the timing chain drive, turn the crankshaft by means of the pulley clockwise (running direction of engine  until U6 marking on pulley coincides with fixing bore in crankcase (60° before TDC)  . Fix with locating pin 9595/1  .
   Fig 2: Locating Mark On Pulley

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2. Turn the engine on the assembly support until cylinder bank 4 - 6 stands vertically upwards.
3. Oil the bearing surfaces of the camshafts with new engine oil.
4. Insert inlet camshaft 4-6. Pull the timing chain out of the chain housing of the cylinder head with a welding wire and position on the ring gear of the camshaft adjuster, at the same time inserting the camshaft at overlapping TDC of cylinder 4 (the cams of cylinder 4 point towards the bulkhead of the flat-base tappet housing -arrows-  ).
   Fig 3: Inserting Camshaft At Overlapping TDC Of Cylinder

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   Fig 4: Locating Bulkhead Of Flat-Base Tappet Housing

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   Information 

   • Make sure that the bearing sleeve on the inlet camshaft is positioned correctly  .
5. The bearing sleeve of the inlet camshaft must be positioned so that the centrally bored blind hole points vertically upwards -arrow-  (the rib of the cylinder head should also be at the center in relation to the bearing sleeve).

   In this position, the dowel pin in the bearing bore of the cylinder head will fit precisely into the opposite off-center blind hole bore. Any other bores are through-holes for guiding the oil.

   Fig 5: Positioning Bearing Sleeve For Inlet Camshaft

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6. Insert outlet camshaft 4-6. Lay the timing chain on the flange for the sprocket, then insert the camshaft at overlapping TDC of cylinder 4 (the outlet cams of cylinder 4 point towards the cams of the inlet camshaft -arrows-  ).
   Fig 6: Locating Outlet Camshaft

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7. Insert outlet camshaft sprocket in the timing chain and position on camshaft flange. The four threaded bores in the camshaft flange must be covered approximately half way by the slots of the sprocket in the clockwise running direction of the engine  - -arrows-  .
   Fig 7: Locating Sprocket In Clockwise Running Direction Of Engine

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8. Oil the bearing surfaces of the camshafts with new engine oil.

   Information 

   • Do not interchange the thrust bearings of the inlet and outlet camshafts during assembly; observe identification markings  .
9. Insert three thrust bearings and one housing -arrows-  for the bearing sleeve of the camshafts together with the guide rail for the timing chain.
   Fig 8: Locating Thrust Bearings And Housing

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10. Insert eight housing screws.
    1. 10.1. Six M6 x 35 and two M6 x 40 Torx screws for camshaft bearing and guide rail.
       Fig 9: Identifying Housing Screws

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    2. 10.2. Tighten screws evenly and just finger-tight.