Connecting Rod Bearings
Rod Bearing Clearance Inspection1. Remove the connecting rod cap and bearing half.
2. Clean the crankshaft rod journal and bearing half with a clean shop towel.
3. Place a strip of plastigage across the rod journal.
4. Reinstall the bearing half and cap, and torque the bolts (see step 16). Do not rotate the crankshaft.
5. Remove the rod cap and bearing half and measure the widest part of the plastigage.
Connecting Rod Bearing-to-Journal Oil Clearance:
Standard (New): 0.020 - 0.044 mm (0.0008 - 0.0017 inch)
Service Limit: 0.060 mm (0.0020 inch)
6. If the plastigage measures too wide or too narrow, remove the upper half of the bearing, install a new, complete bearing with the same color code, and recheck the clearance. Do not file, shim, or scrape the bearings or the caps to adjust clearance.
7. If the plastigage shows the clearance is still incorrect, try the next larger or smaller bearing (the color listed above or below that one), and check clearance again. If the proper clearance cannot be obtained by using the appropriate larger or smaller bearings, replace the crankshaft and start over.
Rod Bearing Selection
Connecting Rod Bore Code Locations
1. Inspect the connecting rod for cracks and heat damage.
2. Each rod has a tolerance range (from 0 to 0.024 mm (0.0009 inch), in 0.006 mm (0.0002 inch) increments) depending on the size of its big end bore. It's then stamped with a code (1, 2, 3, or 4/I, II, III, or IIII) indicating the range. You may find any combination of 1, 2, 3, or 4/I, II, III, or IIII in any engine. If you cannot read the codes because of an accumulation of dirt and dust, do not scrub them with a wire brush or scraper. Clean them only with solvent or detergent. Half of the number or bar is stamped on the bearing cap and the other half is stamped on the rod.
Normal Bore Size: 58.0 mm (2.28 inch)
Connecting Rod Journal Code Locations (Letters or Bars)
3. Letters or bars have been stamped on the crankshaft No. 1 web as a code for the rod journal sizes.
4. Use the connecting rod bore codes and journal codes to select the appropriate rod bearings from the table.