Removing and Installing Cylinder Head - Engine Removed
WM 157019 Removing and installing cylinder head - engine removed
Preliminary work for removing cylinder head
Preliminary work for removing cylinder head
1. Remove exhaust manifold. Remove old seal.
2. Remove cylinder head cover.
3. Remove camshafts.
Caution:
Interchanged or dirty bucket tappets.
Damage to engine components.
- The components have been run in the fitting bores in the housing, therefore do not interchange them.
- Absolute cleanliness is essential.
Information:
There must be no visible signs of wear on the flat-base tappets and fitting bores of the flat-base tappet housing.
4. Remove the bucket tappets. Pull each of the components out of the bucket tappet housing using a strong magnet. Check running surfaces for signs of damage. To avoid confusing the individual bucket tappets, lay them on a labeled, clean surface and cover them.
Example of laying aside bucket tappets
5. Remove bucket tappet housing. Unscrew eleven Torx screws -1- from the outside to the inside. Remove housing and check the fitting bores for damage.
Bucket tappet housing bolts
6. Remove the old O-rings at the spark-plug recesses.
Removing cylinder head
Removing cylinder head
Caution:
Risk of damage due to particles of dirt.
Danger of material damage due to blocked oil bores/oil ducts.
- 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.
Cylinder head 1-3:
1. Unscrew M6 threaded bolt (hexagon socket) for guide rail (flywheel side) -1-.
Guide rail screw for cylinders 1-3
2. Unscrew four Torx screws with M6 x 30 captive washers (10.9) -1 to 4- at the chain slot. Use of a magnetic bit is recommended so that the screw to be fitted in the slot -item 4- cannot fall into the crankcase.
External cylinder head screwed connection
3. Loosen and unscrew twelve M10 Torx cylinder-head screws from outside to inside.
4. Carefully lift off the cylinder head and remove the old cylinder-head gasket.
5. Carefully clean the sealing faces on the cylinder head and crankcase (e.g. using a nylon brush and a clean, lint free cloth soaked in acetone). Check the sealing face from cylinder head to crankcase for damage and cracks, and rework the flat surface if necessary.
Removal of cylinder head 4-6 is the same as for side 1-3 with the following change:
- The threaded bolt for guide rail 4-6 on the cylinder head (belt pulley side) -1- is removed even before the camshaft timing gears are removed.
Guide rail screw for cylinders 4-6
Installing cylinder head
Installing cylinder head
Caution:
Risk of damage due to particles of dirt.
Danger of material damage due to blocked oil bores/oil ducts.
- 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.
Fitting cylinder head side 1 - 3:
1. Turn the crankcase at the assembly support in such a way that side 1-3 stands vertically upwards.
2. Fit new cylinder head gasket. The marking 'OBEN/TOP' must be clearly visible.
3. Carefully position the cylinder head on the crankcase. Pay attention to the dowel sleeves.
4. Screw in twelve M10 Torx screws evenly and tighten according to the prescribed tightening sequence -1 to 12- in 5 steps (see table).
Tightening sequence for cylinder-head screws
5. Screw in and tighten four Torx screws with M6 x 30 captive washers (10.9) -1 to 4- at the chain slot. Use of a magnetic bit is recommended so that the screw to be fitted in the slot -item 4- cannot fall into the crankcase. - Tightening torque: 13 Nm (9.5 ftlb.)
External cylinder head screwed connection
6. Fit threaded bolt for guide rail -1- with anew O-ring at the cylinder head. - Tightening torque: 10 Nm (7.5 ftlb.)
Guide rail screw for cylinders 1-3
Cylinder head side 4-6 is installed in the same way as the assembly sequence for side 1-3 with the following change:
- The threaded bolt for guide rail 4-6 on the cylinder head (belt pulley side) -1- is inserted only after the timing chain has been fitted on the camshaft timing gears.
Guide rail screw for cylinders 4-6
Subsequent work for installing cylinder head
Subsequent work for installing cylinder head
1. Insert three new O-rings at the spark-plug recesses -arrows- and lightly coat with high-pressure grease (Optimol Optipit).
O-rings on spark-plug recess seal
Information:
There must be no visible signs of wear on the flat-base tappets and fitting bores of the flat-base tappet housing.
2. Insert bucket tappet housing with eleven M6 x 35 Torx screws -1-. Tighten screws from the inside out and in diametrically opposite sequence. - Tightening torque: 10 Nm (7.5 ftlb.)
Bucket tappet housing screws
Caution:
Interchanged or dirty bucket tappets.
Damage to engine components.
- The components have been run in the fitting bores in the housing, therefore do not interchange them.
- Absolute cleanliness is essential.
3. Coat the bucket tappets with new engine oil and insert them in their original position into the fitting bores in the bucket tappet housing. The operating plunger position (inlet side) is pre-set by the dowel pin -arrow-.
Operating plunger position
4. Install camshafts and set timing.
5. Install cylinder head cover.
6. Fit exhaust manifold with new screws M8 x 26. Position new metal seal with the seam towards the cylinder head. Tighten screws from the inside out and in diametrically opposite sequence.
- Tightening torque: 23 Nm (17 ftlb.)