26. Crankshaft and Bearing Clean and Inspect
Crankshaft and Bearings Cleaning and InspectionCrankshaft Cleaning and Inspection
- Tools Required
- J 7872 Magnetic Base Dial Indicator Set
Important: Use care when handling the crankshaft. Avoid damage to the bearing surfaces.
1. Clean the oil, sludge, and carbon from the crankshaft with solvent.
2. Thoroughly clean all oil passages and inspect for restrictions and burrs.
Caution: Refer to Safety Glasses Caution in Service Precautions.
3. Dry the crankshaft with compressed air.
4. Inspect the keyway.
5. Perform a visual inspection of the crankshaft for damage.
Important: Replace the crankshaft if cracks, severe gouges or burned spots are found. Slight roughness may be removed with a fine polishing cloth soaked in clean engine oil. Burrs may be removed with a fine oil stone.
6. Inspect the crankshaft journals (1) for wear. The journals should be smooth with no signs of scoring, wear, or damage.
7. Inspect the crankshaft journals for grooves and scoring (2).
8. Inspect the crankshaft journals for roughness and scratches (3).
9. Inspect the crankshaft journals for pitting or imbedded bearing material (4). Inspect the corresponding bearing inserts for imbedded foreign material. If foreign material exists, find the cause and repair it.
10. Inspect the crankshaft bearings for craters or pockets. Flattened sections on the bearing halves also indicate fatigue.
11. Inspect the crankshaft bearings for excessive scoring or discoloration (overheating).
12. Inspect the crankshaft bearings for dirt or debris imbedded into the bearing material.
13. Inspect the crankshaft bearings for improper seating indicated by bright, polished sections of the bearing.
If the lower half of the bearing is worn or damaged, replace both upper and lower halves.
Generally, if the lower half is suitable for use, the upper half should also be suitable for use.
14. Measure the crankshaft connecting rod and main bearing journals for out-of-round.
Measure each journal in 2 places 90 degrees apart. The difference between these 2 measurements is the out-of-round of the journal.
Maximum Out-of-Round 0.01 mm (0.0004 inch)
15. Measure the crankshaft journals for taper.
Measure the journal at each end of the journal. The difference between these 2 measurements is the taper of the journal.
Maximum Taper 0.01 mm (0.0004 inch)
16. Regrind or replace the crankshaft if the above measurements exceed specifications.
17. Note the location of the main bearing high spots. If they are not in line, the crankshaft is bent and must be replaced.
18. Measure the crankshaft runout. Support the crankshaft on the front and rear journals using wooden V blocks.
19. Measure the crankshaft runout at the center journal using the J 7872.
20. Replace the crankshaft if the measurements exceed specifications.
Maximum Runout 0.06 mm (0.0023 inch)
21. Measure the flywheel (2) surface runout using the J 7872.
22. Replace or repair the flywheel if the runout exceeds specifications.
Maximum Runout 0.2 mm (0.0078 inch)
Important: The lower crankcase must be installed and properly torqued in order to measure crankshaft end play.
23. Measure the crankshaft end play using the J 7872.
Standard Crankshaft End Play 0.10 - 0.35 mm (0.0039 ~ 0.0138 inch)
Maximum Crankshaft End Play 0.42 mm (0.0165 inch)
24. The crankshaft thrust bearing is available in standard and oversized.
Standard Thrust Bearing Thickness 2.500 mm (0.984 inch)
0.125 mm (0.0049 inch) Oversize Thrust Bearing Thickness 2.563 mm (0.1009 inch)
25. If the end play exceeds the maximum replace the thrust bearing with a new standard size thrust bearing. If the end play still exceeds the maximum replace the thrust bearing with a new oversize thrust bearing.
Crankshaft Main Bearing Cap Bolts
Cleaning and Inspection
1. Clean the main bearing cap bolts. Compare the main bearing cap bolts to a known good bolt (2) if necessary.
2. Inspect the main bearing cap bolts for the following:
- Damaged threads
- Stretching (1)
- Damaged heads caused by improper use of tools
3. Replace the main bearing cap bolts as necessary.
Crankshaft Main Bearing Selection
Notice: Do not shim, scrape, or file bearing inserts. Do not touch the bearing surface of the insert with bare fingers. Skin oil and acids will etch the bearing surface.
1. The crankshaft bearings are of the precision insert type. The crankshaft bearings are available in standard and 0.25 mm (0.0098 inch) undersized. Undersized refers to crankshaft diameter. Both standard and undersized bearings are each available in 5 sizes (tolerances) differing in thickness in the center of the bearing. The upper bearing half has an oil groove, the lower bearing half does not have an oil groove.
Important: If crankshaft bearing failure is due to other than normal wear, investigate the cause. Inspect the crankshaft bearing bores.
2. Inspect the crankshaft main bearing bores using the following procedure:
2.1. Tighten the lower crankcase cap to specification.
2.2. Measure the bearing bore for taper and out-of-round.
2.3. No taper or out-of-round should exist.
3. Install the original crankshaft main bearing inserts on to the cylinder block and the lower crankcase assembly.
4. Carefully place the crankshaft on to the bearing inserts in the cylinder block.
Important: Do not turn the crankshaft while measuring the bearing clearance.
5. Lay a piece of gaging plastic across each crankshaft main journal (avoiding the oil hole).
6. Carefully place the lower crankcase assembly on to the cylinder block.
Notice: Refer to Fastener Notice in Service Precautions.
7. Install the 10 main bearing cap bolts (1-10). Progressively torque the main bearing cap bolts using 2 steps in the sequence shown.
7.1. Tighten the main bearing cap bolts to 42 Nm (31 ft. lbs.).
7.2. Tighten the main bearing cap bolts to 60 Nm (44 ft. lbs.).
8. Install the 12 lower crankcase bolts (11-22). Progressively torque the lower crankcase bolts using 2 steps in the sequence shown.
8.1. Tighten the 12 lower crankcase bolts to 19 Nm (14 ft. lbs.).
8.2. Tighten the 12 lower crankcase bolts to 27 Nm (20 ft. lbs.).
9. After reaching the proper torque, remove the lower crankcase bolts and the crankshaft main bearing cap bolts.
10. Carefully remove the lower crankcase assembly from the cylinder block.
11. Measure the gaging plastic at its widest point.
Standard Oil Clearance: 0.026 - 0.046 mm (0.0010 - 0.0018 inch)
Maximum Oil Clearance: 0.060 mm (0.0023 inch)
12. A new standard bearing may produce the correct oil clearance. If not, regrind the crankshaft and install 0.25 mm (0.0098 inch) underseas bearings.
13. Crankweb number 2 is stamped with numbers. The numbers represent the corresponding journal diameter marked with an arrow. If using a standard bearing, replace it with one having the same color. If the color of the bearing cannot be determined, select the correct bearing by interpreting the numbers and letters imprinted on the cylinder block and crankshaft.
- Number 1 represents a journal diameter of 57.994 - 58.000 mm (2.2832 - 2.2834 inch).
- Number 2 represents a journal diameter of 57.988 - 57.994 mm (2.2830 - 2.2832 inch).
- Number 3 represents a journal diameter of 57.982 - 57.988 mm (2.2828 - 2.2829 inch).
14. The lower crankcase is stamped with letters. The letters represent the crankshaft bearing cap bore diameter without the bearings installed.
- Letter A represents a crankshaft bearing cap bore diameter of 62.000 - 62.006 mm (2.4409 - 2.4411 inch).
- Letter B represents a crankshaft bearing cap bore diameter of 62.006 - 62.012 mm (2.4412 - 2.4414 inch).
- Letter C represents a crankshaft bearing cap bore diameter of 62.012 - 62.018 mm (2.4414 - 2.4416 inch).
15. There are 5 standard bearings available. The bearings differ in thickness at the center of the bearing. Each bearing is marked with paint (1). The color of the paint indicates the thickness of the bearing.
- Green paint indicates a bearing thickness of 1.993 - 1.997 mm (0.0785 - 0.0786 inch).
- Black paint indicates a bearing thickness of 1.996 - 2.000 mm (0.0786 - 0.0787 inch).
- No paint (colorless) indicates a bearing thickness of 1.999 - 2.003 mm (0.0787 - 0.0788 inch).
- Yellow paint indicates a bearing thickness of 2.002 - 2.006 mm (0.0788 - 0.0789 inch).
- Blue paint indicates a bearing thickness of 2.00 ~ 2.009 mm (0.0789 - 0.0790 inch).
16. Refer to the standard main bearing selection table. Using the intersection of the letters and numbers, select the correct bearing from the table. Measure the oil clearance. If the oil clearance is incorrect install the next thicker bearing and recheck the oil clearance.
Undersized Main Bearing Selection
1. If new standard bearings do not produce the correct oil clearance, regrind the crankshaft to a finished diameter of 57.732 - 57.750 mm (92.2729 - 2.2736 inch) and install 0.25 mm (0.0098 inch) undersized bearings. Undersized bearings are available in 5 sizes (tolerances) differing in thickness in the center of the bearing.
2. Undersized bearings are distinguished from standard size bearings by a double paint mark (1).
- Green and red paint indicates a bearing thickness of 2.118 - 2.122 mm (0.0834 - 0.0835 inch).
- Black and red paint indicates a bearing thickness of 2.121 - 2.125 mm (0.0835 - 0.0836 inch).
- Red paint only indicates a bearing thickness of 2.124 - 2.128 mm (0.0836 - 0.0837 inch).
- Yellow and red paint indicates a bearing thickness of 2.127 - 2.131 mm (0.0837 - 0.0838 inch).
- Blue and red paint indicates a bearing thickness of 2.130 - 2.134 mm (0.0838 - 0.0839 inch).
3. Measure the reground crankshaft journals for out-of-round.
Maximum Out-of-Round 0.01 mm (0.0004 inch)
4. Measure the reground crankshaft journals for taper.
Maximum Taper 0.01 mm (0.0004 inch)
5. Measure the reground crankshaft journals for size.
6. Refer to the undersized main bearing selection table. Using the intersection of the measured journal size and the letters on the lower crankcase select the correct sized bearing from the table. Measure the oil clearance. If the oil clearance is incorrect install the next thicker bearing and recheck the oil clearance.