MTU 12V4000M73 series Operating Instructions Manual page 181

Note: Danger of confusion: There might be an addi-
tional OT/A1 mark (1) on the outer perimeter
of the flywheel.
4. The additional OT/A1 mark (1) (if applicable)
on the outer perimeter of the flywheel must
not be used for reference.
Diagram for 8V engines – Two
crankshaft positions
Diagram for 12V engines – Two
crankshaft positions
MS150045/03E 2018-08 | Valve Drive | 179