5-5
Replacing the conrod bearings
– Clamp each conrod in a vise using protective jaws.
– Loosen the bolts
1
on the conrod bearing covers with the special
wrench socket 600.29.075.000 and remove the bearing covers.
NOTE: mark the conrod caps to ensure that each cap is mounted to the
same conrod when it is measured and assembled.
– Remove the conrod caps.
– Clean the crankshaft and blow compressed air through the lubrication
bores.
Selecting the bearing shells
Before you select the new bearing shells you must measure the conrod
journal.
– Measure the diameter of the conrod journal at 3 points that are 120°
apart using a micrometer gauge.
Diameter of the conrod journal:
41.990 mm – 42.000 mm (blue)
42.001 mm – 42.011 mm (red)
NOTE:
– Use the bearing color indicated for the respective measurement.
– The crankshaft must be replaced if the measurement falls short of the
minimum diameter or if the crankshaft is worn.
– Clamp each conrod in a vise, insert new bearing shells, position the
crankshaft with a plastigauge measuring strip
A
(600.29.012.000) on
top and mount the conrod caps with the old bolts, as described
below.
!
CAUTION
!
–
INSERT THE PLASTIGAUGE MEASURING STRIPS AT A
90°
ANGLE TO THE BEARING
END GAP
.
–
DO NOT TURN THE CONRODS ON THE CONROD JOURNAL
.
– Unclamp the conrods and compare the width of the plastigauge
measuring strip with the information on the packing. The width of
the plastiguage measuring strip is equivalent to the bearing clearance.
Setpoint value of the conrod bearing clearance:
0.030 mm – 0.060 mm
Wear limit: 0.080 mm
– Clamp each conrod in a vise using protective jaws, apply a thin layer
of Molycote grease to the bearing shells, position the crankshaft and
mount the conrod caps with new bolts.
!
CAUTION
!
T
HE BEARING SHELLS SHOULD BE MOUNTED IN AN OFFSET POSITION IN THE CONROD
TO ALLOW ROOM FOR THE CRANKSHAFT RADIUS
2
.
IF THE CONRODS ARE
MOUNTED BACKWARDS
,
THE BEARING SHELLS WILL EXERT PRESSURE ON THE RADIUS
AND BLOCK THE CONRODS
.
– Tighten the conrod bearing bolts with the special wrench socket
600.29.075.000 to 25 Nm (1st stage). The tighten to 30 Nm (2nd
stage) and finally by another 60° (3rd stage).
NOTE: use a degree wheel
3
(600.29.010.000) to make sure the
conrod bearing bolts are tightened correctly.
1
2
2
3
A
