Dismantling and reassembling valve gear - MB/1B/MC-2 engine

Hydraulic tappet cylinder heads

1. Bearing cap
   • Note offset bore - check cap orientation
   • Installing sequence - see Installing camshaft
2. Check torque - 20Nm
3. Camshaft
   • Checking backlash - Fig 1
   • Removing and installing - 15-22
   • Camshaft identification - Fig 2
   • Check radial clearance (bucket tappets removed) with Plastigage - maximum 0.1mm
   • Run-out maximum 0.01mm
4. Oil seal
   • Check seal - crank seal is very similar
   • Renewing - 15-21
5. Hydraulic tappets
   • Checking tappets 15-20
   • Lift out with magnetic retrieval tool - place face down on soft cloth in oil
   • Store in valve order for replacement
   • Wipe and oil contact surface when replacing
6. Cotters
   • Removing - 15-25
7. Upper valve spring seat
8. Outer valve spring
   Inner valve spring
9. Valve stem oil seal
   • Renewing - 15-25
10. Lower valve spring seat
    • Remove/replace with VAG 3047-A or magnetic tool
    • Note seat captive under valve stem oil seal
11. Valve guide
    • Note original has no shoulder
    • Checking for wear - 15-24
    • Renewing - 15-24
12. Valve guide - replacement
    • Note shoulder
13. Cylinder head
    • Reworking valve seats - 15-18
    • Checking for distortion - 15-10
14. Valves
    • Lap in by hand only - do not rework
    • Exhaust valves contain sodium metal - dispose of carefully
    • Valve dimensions - Fig 4
15. Rework dimension for cylinder head
    • Minimum dimension 132.75mm