Measuring Main Bearing Bores and Fitting New Bearings
Mounting Crankshaft Radially In Bearings1. Remove crankshaft.
2. Disassemble and clean engine.
3. Clean and inspect crankshaft.
4. Install and tighten bearing cap to 30 Nm
5. Measure and note bearing bore diameter.
6. Measure and note crankshaft bearing journal diameter.
7. Match bearing shells. Refer to illustration.
Example:
Bearing bore diameter 62.51 mm
Crankshaft journal diameter - 57.95 mm _______
4.55 mm
Radial bearing play - 0.04 mm _______
Bearing shell thickness 4.51 mm/2 = 2.25 mm
CAUTION: When determining different bearing shells, match thicker bearing shell to the bearing cap.
NOTE: Top bearing shell "blue". Bottom bearing shell "blue".
8. Calculate the likely radial bearing play.
9. Blow bolt holes clean.
10. Insert bearing shells into crankcase and bearing cap.
11. Tighten bearing cap bolts to 30 Nm.
12. Measure bearing diameter.
13. Calculate radial bearing play (real play).
- Specification: 0.035 - 0.045 mm
14. Remove bearing cap.
15. Oil bearing shells in crankcase.
16. Oil crankshaft at bearing points.
17. Oil bearing caps with bearing shells.
18. Oil thread and contact surface of bolts.
NOTE: Re-use bolts up to a maximum of 63.8 mm.
19. Tighten bearing cap bolts to 55 Nm + 90° tightening angle.
CAUTION: Rotate crankshaft while tightening the bolts in order to detect any jamming in good time.
Test Specifications
Crankshaft Bearing Play:
Axial: 0.100 - 0.250 mm
Radial: 0.030 - 0.045 mm
Conrod Radial Bearing Play: 0.020 - 0.050 mm