Crankshaft Main Bearing
BEARING CLEARANCEUse Method A or Method B. Method A is preferred because it is more accurate.
Method A (Using bore gauge and micrometer)
Main bearing
1. Set main bearings in their proper positions on cylinder block and main bearing cap.
2. Install main bearing cap to cylinder block. Tighten all bolts in correct order in two or three steps.
3. Measure inner diameter "A" of each main bearing.
4. Measure outer diameter "Dm" of each main journal in crankshaft.
5. Calculate main bearing clearance.
Main bearing clearance = A - Dm
Standard: 0.018 - 0.042 mm (0.0007 - 0.0017 inch)
Limit: 0.1 mm (0.004 inch)
^ If it exceeds the limit, replace bearing.
^ If clearance cannot be adjusted within standard of any bearing, grind crankshaft journal and use undersized bearing.
When grinding crank pin and crank journal:
^ Grind until clearance is within specified standard bearing clearance.
^ Fillets should be finished as shown in the figure. R: 2.3 - 2.5 mm (0.091 - 0.098 inch) Refer to EM-93, "Bearing Clearance" for standard bearing clearance and available spare parts.
6. If the crankshaft is replaced, select thickness of main bearings as follows:
a. Grade number of each cylinder block main journal is punched on the respective cylinder block. These numbers are punched in either Arabic or Roman numerals.
b. Grade number of each crankshaft main journal is punched on the respective crankshaft. These numbers are punched in either Arabic or Roman numerals.
c. Select main bearing with suitable thickness according to the following table.
For example:
Cylinder block main journal grade number: 1
Crankshaft main journal grade number: 2
Main bearing grade number = 1 + 2 = 3 (Yellow)
Connecting Rod Bearing (Big End)
1. Install connecting rod bearing to connecting rod and cap.
2. Install connecting rod cap to connecting rod.
3. Install connecting rod caps.
a. Apply new engine oil to bolt threads and nut seating surfaces.
b. Tighten connecting rod cap nuts in two steps:
Step 1: 13.72 - 15.68 Nm (1.399 - 1.599 kg-m, 10.120 - 11.566 ft. lbs.)
Step 2: 35 - 40 degrees clockwise, or 23 - 28 Nm (2.3 - 2.9 kg-m, 17 - 21 ft. lbs.)
4. Measure inner diameter "C" of each bearing.
5. Measure outer diameter "Dp" of each crankshaft pin journal.
6. Calculate connecting rod bearing clearance.
Connecting rod bearing clearance = C - Dp
Standard: 0.014 - 0.039 mm (0.0006 - 0.0015 inch)
Limit: 0.1 mm (0.004 inch)
^ If it exceeds the limit, replace bearing.
^ If clearance cannot be adjusted using any standard bearing grade, grind crankshaft journal and use undersized bearing. Refer to EM-93, "Bearing Clearance".
^ If a new bearing, crankshaft or connecting rod is replaced, select connecting rod bearing according to the following table.
NOTE: These numbers are punched in either Arabic or Roman numerals.
Method B (Using Plastigage)
CAUTION:
^ Do not turn crankshaft or connecting rod while Plastigage is being inserted.
^ If incorrect bearing clearance exists, use a thicker or undersized main bearing to ensure specified clearance.
Main Bearing Cap
Install crankshaft and main bearing caps and tighten bolts in the order shown.
Main bearing cap bolts 46.1 - 52.0 Nm (4.780 - 5.30 kg-m, 34.0 - 38.8 ft. lbs.)
Apply new engine oil to the bolt thread and seat surface.
Prior to tightening bearing cap bolts, shift crankshaft back and forth to properly seat the bearing caps.
Tighten bearing cap bolts gradually in two or three stages. Start with center bearing and move outward as shown in figure.
After securing bearing cap bolts, make sure crankshaft turns smoothly by hand.
Main Bearing
STANDARD:
STANDARD
UNDERSIZE:
UNDERSIZE
Bearing Clearance:
Main Bearing Clearance