Detroit Diesel — Assemble Crankshaft Halves (12V And 16V)
Repair & overhaul
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- The 12V and 16V crankshaft outboard bearing surface must not be reduced in diameter.
Procedure
- Install the upper grooved main bearing shells in the cylinder block.
- Apply clean engine oil to all crankshaft journals and place each crankshaft half in position.
- Install the upper halves of the crankshaft thrust washers and the doweled lower halves; grooved side faces the crankshaft thrust surface.
- Install all bearing caps except the two center caps and draw the bolts up snug; rap the caps with a soft hammer.
- Tighten each set of main bearing cap bolts to approximately 100 lb-ft, then to 280-290 lb-ft.
- Position a dial indicator on the two center journals and check the journal runout.
- Rotate the crankshaft halves until the timing marks are in alignment; install the 7/16" bolts.
- Install two 1/2" bolts and nuts 120° apart; snug up the three bolts while rotating the crankshaft to bring runout within .001".
- Install the remaining bolts and nuts and alternately torque to specification.
- Install the crankshaft oil passage plugs.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Main bearing cap bolts 100 lb-ft then 280-290 lb-ft (379-393 N·m)
- 7/16" nut 70-80 lb-ft; 1/2" nuts 100-110 lb-ft
- Two center journals must be concentric within .001" TIR
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.