MTU 12 V 4000 L62FB Operating Instructions Manual page 145

Valve protrusion – Measurement
1. Check TDC position of piston in cylinder A1:
• If the rocker arms are unloaded on cylinder A1, the piston is in firing TDC.
• If the rocker arms are under load on cylinder A1, the piston is in overlap TDC.
2. Measure valve protrusion for each valve in two crankshaft positions (firing TDC and overlap TDC cylinder A1)
according to the diagram. Diagram (→ Page 141).
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 spark plug bore
with sliding depth gauge (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, have
the relevant cylinder head replaced by au-
thorized personnel ahead of schedule .
5. Install valve bridge.
6. Valve clearance – Adjustment(→ Page 141)
Final steps
1. Remove barring tool (→ Page 128).
2. Check condition of O-rings at the sleeves, replace O-rings if damaged.
MS150098/02E 2016-11 | Valve Drive | 145