Fitting Bearings
Engine 604 Shown, Engine 606 Similar:
REMOVAL
- Remove crankshaft
- Clean engine components
- After damage has occurred to the bearings, any swarf (metal particles) in the conrod bores and in the oil galleries of the crankshaft and crankcase has to be removed
- Clean main oil gallery and seal
INSPECTION
- Inspect conrod
After damage has occurred to the bearings:
Replace conrods which have been overheated because of bearing damage (blue discoloration).
The conrod shank must not have any cross scores and notches.
- Inspect crankshaft
After damage has occurred to the bearings:
Visual inspection
If damage present, inspect crankshaft, repair
MEASUREMENT
Crankshaft Radial Bearings
1. Install crankshaft bearing caps.
NOTE:
^ The crankshaft bearing caps are inserted into the side of the crankcase with an interference fit.
^ The interference fit is off-centered 0.5 mm so that the bearing caps can only be installed in one position.
^ If they are correctly installed, the lug (arrow) on the crankshaft bearing cap is pointing to the left (intake side) when looking in the direction of travel.
^ The crankshaft bearing caps are machined together with the crankcase and must not be mixed up.
2. Measure crankshaft bearing bore at two levels in the directions A, B and C (concentricity).
NOTE: If the measurement obtained for the crankshaft bearing bore exceeds the specification or if the bearing bore is out of roundness, dress the contact surface of the bearing cap on a dressing plate up to max. 0.02 mm.
3. Measure crankshaft bearing bore in direction A, note the measurement.
Example: 62.51 mm
4. Take off crankshaft bearing caps.
5. Measure crankshaft bearing journal diameter.
Example: 57.95 mm
6. Calculate thickness of bearing shell
Example:
Bearing bore diameter minus bearing journal diameter minus desired bearing play (From Specifications) equals total bearing thickness divided by two equals thickness of each bearing shell.
Bearing bore: 62.51 mm
Bearing journal: - 57.95 mm ______
Equals: 4.55 mm
Radial play desired: - 0.04 mm ______
Bearing shell:
Total thickness: 4.51 mm
Divided in half: ÷2 ______
Equals: 2.255 mm
7. Match the bearing shells.
Example:
Bearing shell thickness 2.255 mm
Refer to "Bearing Fit Tables" below.
Top bearing shell "blue"
Bottom bearing shell "blue"
NOTE: If the thickness of the bearing shells differs, install the thicker bearing shell in the bearing cap
Crankshaft Axial (End Play) Bearings
1. Measure width of fit bearing at crankcase and at fit bearing cap and note.
2. Measure width of fit bearing at crankshaft and note.
3. Determine thickness of thrust washer.
CAUTION: Thrust washers of the same thickness must always be inserted on one side in the crankcase and in the fit bearing cap.
4. Install thrust washers.
- The oil groove must face towards the contact surface of the crankshaft and be oiled.
- The anti-twist lock is on the thrust washer in the bearing cap.
5. Measure axial bearing plait and adjust to correct size, if necessary.
ADJUSTMENT
- Using the following tables, fit bearings to the block and crankshaft to achieve a main bearing clearence of:
Main Bearing Radial Clearence:
New: 0.03-0.05 mm
Wear Limit: 0.08 mm
Main Bearing Axial Clearence:
New: 0.03-0.05 mm
Wear Limit: 0.08 mm
- Standard Sizes:
Basic Main Bearing Bore In Block, Diameter: 62.50-62.52 mm
Basic Bore In Block Width At Install Bearing: 23.98- 24.00 mm
Permissible Out Of Round And Concentricity: 0.02 mm
Standard Crankshaft, Diameter (58.00 mm)
1st. Undersize Crankshaft, Diameter (57.75 mm)
2nd. Undersize Crankshaft, Diameter (57.50 mm)
3rd. Undersize Crankshaft, Diameter (57.25 mm)
4th. Undersize Crankshaft, Diameter (57.00 mm)
BEARING FIT TABLES
- Bearing Shells For Standard Crankshaft
Part No. Modifier Code 52, Color Blue
Shell Thickness: 2.255-2.260 mm
Part No. Modifier Code 54, Color Yellow
Shell Thickness: 2.260-2.265
Part No. Modifier Code 56, Color Red
Shell Thickness: 2.265-2.270 mm
Part No. Modifier Code 57, Color White
Shell Thickness: 2.270-2.275
Part No. Modifier Code 58, Color Purple
Shell Thickness: 2.275-2.280 mm
- Bearing Shells For 1st. Undersize Crankshaft
Part No. Modifier Code 52, Color Blue
Shell Thickness: 2.380-2.385 mm
Part No. Modifier Code 54, Color Yellow
Shell Thickness: 2.385-2.390 mm
- Bearing Shells For 2nd. Undersize Crankshaft
Part No. Modifier Code 52, Color Blue
Shell Thickness: 2.500-2.505 mm
Part No. Modifier Code 54, Color Yellow
Shell Thickness: 2.505-2.510 mm
- Bearing Shells For 3rd. Undersize Crankshaft
Part No. Modifier Code 52, Color Blue
Shell Thickness: 2.625-2.630 mm
Part No. Modifier Code 54, Color Yellow
Shell Thickness: 2.630-2.635 mm
- Bearing Shells For 4th. Undersize Crankshaft
Part No. Modifier Code 52, Color Blue
Shell Thickness: 2.750-2.755 mm
Part No. Modifier Code 54, Color Yellow
Shell Thickness: 2.755-2.760 mm
- Install crankshaft
- Test crankshaft bearing play
- Install Crankshaft bearing caps
Tighten main bearing caps in two stages as follows:
1st stage, tighten to: 55 Nm
2nd stage, turn: an additional 90°
- Install in the reverse order