MTU 12 V 4000 L62FB Operating Instructions Manual page 142

Diagram for 12V engines – Two
crankshaft positions
Diagram for 16V engines – Two
crankshaft positions
1 Cylinder A1 is in firing TDC
2 Cylinder A1 is in overlap TDC
I Inlet valve
X Exhaust valve
Checking valve clearance at two crankshaft positions
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. Check valve clearance adjustment with cold engine:
• Inlet valves (long rocker arm) = 0.3 mm
• Exhaust valves (short rocker arm) = 0.5 mm
3. Check all valve clearances in two crankshaft positions (firing TDC and overlap TDC of cylinder A1) as per
diagram.
4. Use feeler gage to determine the distance between valve bridge and rocker arm.
5. If the deviation from the set value exceeds 0.1 mm, adjust valve clearance.
142 | Valve Drive | MS150098/02E 2016-11