WÄRTSILÄ RT-flex50-D, Руководство по обслуживанию

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Maintenance
3303−1/A1
RT-flex50-D
Wärtsilä Switzerland Ltd
3/ 5
3. Tensioning the stud of bottom end bearing
⇒
Clean the threads of studs 4 as well as the area around nuts 5.
⇒
Apply oil to the stud threads and screw on the nuts.
⇒
Tighten the nuts with round bar ’RS’ and equally distribute clearance ’y’ be-
tween the bearing halves (bearing protrusion) as shown in Fig. ’B’.
⇒
Place distance bushes 94314a onto the studs.
⇒
Fit and tighten pre-tensioning jacks 94314 with open vent screws 7 until there
is only little or no clearance at ’x’ (Fig. ’C’).
⇒
Connect the pre-tensioning jacks to hydraulic unit 94942 as shown in Fig. ’B’.
⇒
Actuate the hydraulic unit till bubble-free oil flows out through the vent screws.
Close vent screws.
⇒
Actuate the hydraulic unit and set pressure to 950 bar (1
st
step) and keep
pressure constant.
Pistons 8 of the pre-tensioning jacks must never exceed the red limiting grooves
’BN’ (Fig. ’C’).
Tighten the nuts with round bar ’RS’ and check with the feeler gauge through slot
’KO’ (Fig. ’C’) that no clearance remains between nut and supporting surface.
Check with the feeler gauge that no clearance remains between bearing cover and
connecting rod.
(Should clearance remain, loosen the fastening and compare the bearing protru-
sion with the nominal value as indicated in
3303−2 ).
⇒
After tensioning to the 1
st
step mark the position of
the nuts against connecting rod as shown in Fig. ’a’.
⇒
Raise the pressure to 1500 bar (2
nd
step) and keep it
constant.
Tighten nuts down and check correct seating with the
feeler gauge.
Check from the markings applied by how much the nuts
were turned after pre-tightening (1
st
step).
Tightening angle to be about 30
_
(Fig. ’b’).
⇒
Should considerable differences to these nominal
values be encountered then repeat the tensioning
process.
⇒
Release pressure to ’0’ at the hydraulic unit and then
remove pre-tensioning jacks.
Finally check the vertical bearing clearance (see Clear-
ance Table
0330−1 ’Top and bottom end bearings to con-
necting rod’).
CHECK
CHECK
TIGHTENING
ANGLE
x
y
Fig. ’a’
y
Fig. ’b’
009.752/02
013.430/05
x
Loosening and Tensioning the Connecting Rod Studs
2010
CHECK