MTU 12V4000G34F Operating Instructions Manual page 128

Diagram for 16V engines – Two
crankshaft positions
Diagram for 20V engines – Two
crankshaft positions
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) = 0.2 mm ±0.05 mm
• Exhaust valves (short rocker arm) = 0.5 mm ±0.05 mm
3. Check all valve clearances in two crankshaft positions (firing TDC and overlap TDC of cylinder A1) as per
diagram:
1 Cylinder A1 is in firing TDC
2 Cylinder A1 is in overlap TDC
I Inlet valve
X Exhaust valve
4. Use valve setting gauge or feeler gauge 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.
128 | Valve Drive | MS15060/01E 2018-12