WÄRTSILÄ RT-flex50-D, Maintenance Manual

Page: 179 / 522

Maintenance
2708−2/A1
RT-flex50-D
Wärtsilä Switzerland Ltd
3/ 3
4. Tensioning
Using a feeler gauge, check whether nuts 2 rest
without clearance.
⇒
Mark position of nuts to seating surface with a
felt tipped pen.
⇒
Screw pre-tensioning jacks 94252 onto cylin-
der cover studs 1 as mentioned in section 2,
however, do not turn back them.
⇒
Connect pre-tensioning jacks to hydraulic
unit 94942 and actuate the latter.
⇒
Close vent screws 3 on the pre-tensioning
jacks as soon as oil flows bubble-free.
⇒
Slowly raise the pressure to 1500 bar and
keep it constant.
Pistons 4 of the pre-tensioning jacks must never
exceed the red limiting grooves ’BN’.
⇒
Tighten nuts 2 with round bar ’RS’.
Check seating of the nuts with a feeler gauge
through slot ’KO’.
⇒
Release pressure to ’0’ and remove all pre-
tensioning jacks.
Ascertain that these have been turned by about
the same angle of 255
_
.
CHECK
CHECK
CHECK
C
RS
KO
012.964/05
4
BN
7
2
D
Where it is found that a nut can be turned considerably less than the others, it
must be assumed that the respective cylinder cover stud has become insuffi-
ciently tensioned.
Possible causes:
− Sealing rings 7 defective (Fig. ’C’).
− Piston 4 jams.
− Junctions of HP hoses leaky.
D
To remedy the cause, loosen all cylinder cover studs and then repeat the ten-
sioning procedure.
⇒
Release pressure to ’0’ and remove all pre-tensioning jacks.
Verify that all nuts have been turned equally by an angle of about 255
_
.
Loosening and Tensioning of Cylinder Cover Waisted Studs
2010
CHECK