Wartsila RT-flex50-D - Tensioning Waisted Studs of Piston Crown

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 waiste
d
studs and screw on the nuts.
⇒ Tighten the nuts with round bar ’R
S’
by hand.
Using a feeler gauge, check whether th
e
nuts rest without clearance.
⇒ Mark position of nuts to seating su
r-
face with a felt tipped pen (Fig. ’a’)
.
⇒ Place pre-tensioning jacks 9434
6
crosswise on the waisted studs a
s
shown in Fig. ’A’, and complete
ly
screw them on with opened ve
nt
screws 16 till there is no or little clea
r-
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 o
ut
bubble-free.
⇒ Operate the hydraulic unit till a pressure of 1500 ba
r
is reached.
Pistons 14 of the pre-tensioning jacks must never e
x-
ceed the red limiting grooves ’BN’ (Fig. ’B’).
⇒ Keep the pressure of 1500 bar constant and tighte
n
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 cros
s-
wise according to the sequence for tensioning th
e
remaining waisted studs.
⇒ Remove pre-tensioning jacks.
After tensioning the nuts check if these have bee
n
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