157049 Machining the cylinder head

WM 157049 Machining the cylinder head

Preliminary work

Preliminary work for machining cylinder head

1. Remove cylinder head -> 157019 Removing and installing cylinder head - section on "Removing" 157019 Removing and installing cylinder head.
2. Disassemble cylinder head -> 157037 Disassembling and assembling cylinder head - section on "Disassembling" 15703750 Disassembling and assembling cylinder head.

Machining the cylinder head

CAUTION

Use solvent naphtha or acetone to clean/degrease components.

- Harmful to skin and eyes.

-> Always observe the manufacturer's specifications.
-> Wear appropriate (petrol-resistant) protective gear, such as apron, gloves and goggles.

1. Carefully clean sealing face using solvent naphtha or acetone.
2. Measure cylinder head height on a level surface (surface plate recommended).

Standard dimension -X- : 142.0 +/- 0.05 mm





Cylinder head height

3. Check combustion chamber sealing face of the cylinder head for distortion (flatness) using a straight-edge and feeler gauge.

Permissible unevenness of parting surface for used cylinder head: 0.05 mm





Flatness of sealing face of cylinder head (diagonal)





Flatness of cylinder head (longitudinal)

4. Cylinder heads with a distorted or grooved sealing face can be repaired by surface-milling them. The following machining criteria must be observed:

Permissible unevenness after machining: 0.03 mm

Permissible roughness profile (can be measured with contact stylus procedure): 15pt14

Permissible surface depth from standard dimension: 0.15 +/- 0.05 mm

Subsequent work

Subsequent work for machining cylinder head

1. Assemble cylinder head -> 157037 Disassembling and assembling cylinder head - section on "Assembling" 15703750 Disassembling and assembling cylinder head.
2. Install cylinder head -> 157037 Disassembling and assembling cylinder head - section on "Installing" 15703750 Disassembling and assembling cylinder head.