Detroit Diesel — Install Main Bearing Shells (Crankshaft In Place)
Repair & overhaul · Crankshaft Main Bearings
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- Do not replace one main bearing shell alone; install all new upper and lower bearing shells.
- Do not exceed the specified torque.
Procedure
- Apply clean engine oil 360° around each crankshaft bearing journal and install the upper main bearing shells.
- Install the upper main bearing shell with the tang fitting into the groove in the bearing support.
- Install the lower main bearing shell so the tang fits into the groove in the bearing cap.
- Assemble the crankshaft thrust washers before installing the rear main bearing cap.
- Apply International Compound No. 2 to the bolt threads and bolt head contact areas; install the bearing caps and draw the bolts up snug.
- Use tool J 35371 to tighten each set of main bearing cap bolts to 100 lb-ft, then 280-290 lb-ft.
- Check the crankshaft end play.
- Install the lubricating oil pump intake pipe assembly and oil pump; install the upper and lower oil pans.
- Fill the crankcase to the proper level and operate the engine on a run-in schedule.
Tools required
- Tool J 35371 Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Main bearing cap bolts 280-290 lb-ft (379-393 N·m)
- Bearing shell clearance .0030"-.0062" new; discard if exceeds .0072"
- End bearing shells 2.70" wide; intermediate bearing shells 1.80" wide
Source: Detroit Diesel service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.