11 31 052 Replacing both timing chains (N74)

Necessary preliminary tasks: 

• Remove lower TIMING CASE COVER 
• To facilitate removal and installation of timing chains, turn engine over with special tool 00 2 300

Timing drive, cylinders 1 to 6  .

Remove guide rail (5) from bearing bolt.

Remove timing chain (3) with tensioning rail (4) from bearing bolt.

Timing drive, cylinders 7 to 12  .

Remove guide rail (1) from bearing bolt.

Remove timing chain (2) with tensioning rail (6) from bearing bolt.

Fig 1: Identifying Timing Chain, Guide And Tensioning Rail

Courtesy of BMW OF NORTH AMERICA, INC.

Timing drive, cylinders 1 to 6  .

Release bearing bolts (2) with a suitable tool.

Tightening torque: see 1AZ in 11 31 CAMSHAFT

Timing drive, cylinders 7 to 12  .

Release bearing bolts (1).

Tightening torque: see 2AZ in 11 31 CAMSHAFT

Fig 2: Identifying Bearing Bolts

Courtesy of BMW OF NORTH AMERICA, INC.

Attach special tools 11 2 001 and 11 2 002 to the crankshaft.

Insert special tool 11 2 007 and remove sprocket wheel with special tool 11 2 003 .

Fig 3: Removing Sprocket Wheel Using Special Tool 11 2 003

Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Make sure Woodruff key (1) is installed in correct position in crankshaft (2).

Installation: 

Check sprocket wheels for wear, replace if necessary.

Heat sprocket wheel to 60 °C  .

Fig 4: Identifying Woodruff Key And Crankshaft

Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Maintain tension of timing chains when installing timing case cover.

Observe sparking protection on timing case cover.

Make sure timing chain (1) is correctly installed when placing it in guide rail (3).

Assemble engine.