Wartsila RT-flex50-D - Tensioning the Waisted Studs of Piston Foot Fastening

Maintenance
3403−1/A1
RT-flex50-D
Wärtsilä Switzerland Ltd
3/ 8
3. Tensioning the waisted studs of piston foot fastening
⇒ Clean the threads of waisted studs
3
and the area around nuts 4.
⇒ Apply oil to the threads of the waiste
d
studs and screw on the nuts.
⇒ Tighten the nuts with round bar ’RS
’
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’)
.
⇒ Completely screw the pre-tensionin
g
jacks diagonally onto waisted studs
3
(Fig. ’A’). Moreover, vent screws
5
are to be opened slightly so that pis
-
tons 7 can slide back to their initi
al
position i.e. there is no or very litt
le
clearance at ’x’ (Fig. ’B’).
⇒ Connect both pre-tensioning jacks
to
HP oil pump 94931 as shown in Fig
.
’A’.
⇒ Shut relief valve ’EV’ and start up HP oil pum
p
94931 till bubble-free oil flows out through ven
t
screws 5. Shut the vent screws.
⇒ Slowly raise the pressure to 1500 bar.
Pistons 7 of the pre-tensioning jacks must never excee
d
the red limiting grooves ’BN’ (Fig. ’B’).
⇒ Keep the pressure of 1500 bar constant and tighte
n
nuts 4 with round bar ’RS’ till firmly seated.
⇒ Release pressure to zero with the aid of relief valv
e
’EV’ at the HP oil pump and then screw the pre-ten
-
sioning jacks onto the other two waisted stud
s.
These are to be tensioned in the same sequence a
s
described above.
After tensioning the nuts check their seatings with
a
feeler gauge through slot ’KO’.
After tensioning the nuts check again if these have bee
n
turned by about the same angle i.e. about 80_
,
compared with the marks previously made (Fig. ’b’).
CHECK
CHECK
B
x
Fig. ’a’
y
Fig. ’b’
y
009.752/02
x
010.031/02
PRE-TENSIONING JACK PLACED FOR
TENSIONING LOOSENING
TIGHTENING ANGLE
SA
x
8
RS
7
BN
013.254/05
3
4
KO
5
2010
Piston: Removal and Fitting