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Measuring valve protrusion
1.
Check TDC position of piston in cylinder A1:
• The piston is at firing TDC when the rocker arms on cylinder A1 are unloaded.
• The piston is at overlap TDC when the rocker arms on cylinder A1 are loaded.
2.
Measure protrusion at each valve in two crankshaft positions (firing TDC and overlap TDC) according to the
diagram. Diagram (→ Page 187).
3.
Release adjusting screw (1) and remove valve
bridge. Do not remove rocker arm (2)!
4.
Measure distance between valve stem end
and cylinder head top at the igniter bore with
depth gage (see figure).
• The specified value for a new cylinder
head: 93.8 mm.
• Admissible wear: 3 mm.
• If the measured value is > 96.8 mm, re-
place the relevant cylinder head ahead of
schedule.
5.
Install valve bridge.
6.
Adjust valve clearance (→ Page 187).
Final steps
1.
Remove barring tool (→ Page 173).
2.
Check condition of O-rings at the sleeves, replace if damaged.
190 | Valve Drive | MS150116/04E 2018-04
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