MTU Detroit Diesel 183 Series Technical Publication page 12

Group 00
Subgroup 0001
Page 4
a) Threaded connections without tightening specifications
For threaded connections without tightening specifications, the tightening procedure can be selected as
required, i.e. mechanical tightening with screwdriver or normal manual tightening with an open-end wrench or
box wrench is possible.
In the event of mechanical tightening, the tightening torque must be taken from the general tightening
specifications according to thread size and property class.
b) Threaded connections with tightening instructions - Torque tightening
The screw connections must be tightened by hand with a torque wrench or angle-of rotation torque wrench. The
specified torques must be set at the torque wrench without consideration of the specified tolerance. When using
an angle-of-rotation torque wrench, the torque indicated must be within the torque specification limit value.
Proceed in a similar manner with torsionally protected threaded connections. These instructions apply also to
testing torques.
Note: If no tolerance for tightening torque is stated, the tightening tolerance is + 10% of specified torque.
- Angle-of-rotation tightening:
The additional angles-of-rotation specified in the tightening specifications must be achieved and may be
exceeded within the specified tolerance.
If no tightening tolerance is specified, the following tolerances must be observed:
+ 5° for angle-of-rotation less than or equal to 90°
+ 10° for angle-of-rotation greater than
Before angle-of-rotation tightening, each screw head must be colour-marked so that after tightening it is possible
to check that the angle-of-rotation is correct (Exception: colour-marking is not necessary in the case of a self-
monitoring NC screwdriver).
- Elongation tightening
Tightening must be carried out in accordance with tightening specifications and taking the tightening tolerance
into consideration.
20080/1 E 98-12
90°
General