WÄRTSILÄ RT-flex50-D, Maintenance Manual

Page: 297 / 522

Maintenance
3403−3/A1
RT-flex50-D
Wärtsilä Switzerland Ltd
3/ 6
3. Tensioning waisted studs of piston crown
⇒
Clean the threads of waisted studs 5
and the area around nuts 13.
⇒
Apply oil to the threads of waisted
studs and screw on the nuts.
⇒
Tighten the nuts with round bar ’RS’
by hand.
Using a feeler gauge, check whether the
nuts rest without clearance.
⇒
Mark position of nuts to seating sur-
face with a felt tipped pen (Fig. ’a’).
⇒
Place pre-tensioning jacks 94346
crosswise on the waisted studs as
shown in Fig. ’A’, and completely
screw them on with opened vent
screws 16 till there is no or little clear-
ance at ’x’.
⇒
Connect the pre-tensioning jacks to
the hydraulic unit 94942.
⇒
Start up hydraulic unit.
⇒
Close vent screws 16 as soon as oil flows out
bubble-free.
⇒
Operate the hydraulic unit till a pressure of 1500 bar
is reached.
Pistons 14 of the pre-tensioning jacks must never ex-
ceed the red limiting grooves ’BN’ (Fig. ’B’).
⇒
Keep the pressure of 1500 bar constant and tighten
nuts 13 with round bar ’RS’ till firmly seated.
After tensioning the nuts check their seatings with a
feeler gauge through slot ’KO’.
⇒
Always the same procedure is to be applied cross-
wise according to the sequence for tensioning the
remaining waisted studs.
⇒
Remove pre-tensioning jacks.
After tensioning the nuts check if these have been
turned by about the same angle, i.e. approx. 115
_
compared with the marks previously made (Fig. ’b’).
CHECK
CHECK
PRE-TENSIONING JACK PLACED FOR
TENSIONING LOOSENING
x
Fig. ’a’
Fig. ’b’
y
x
011.675/04
y
TIGHTENING
ANGLE
CHECK
B
015.888/07
C
SA
x
16
5
13
RS
14
BN
15
KO
4
2010
Piston: Removal and Fitting