11 21 500 Replacing crankshaft (N74)

Risk of injury  from sharp crankcase edges.

Necessary preliminary tasks: 

• Remove ENGINE 
• Mount engine on assembly stand
• Remove cylinder head. See LEFT CYLINDER HEAD /RIGHT CYLINDER HEAD .
• Remove HUB FOR VIBRATION DAMPER 
• Removing lower timing case cover
• REMOVING OIL PAN 
• Remove OIL PUMP 
• Removing PISTON 
• Remove FLYWHEEL 
• Remove radial shaft seals. See RADIAL SEAL ON TRANSMISSION SIDE  and RADIAL SHAFT SEAL IN LOWER TIMING CASE COVER .
• Remove TIMING CHAINS 

Installation: 

Arrangement of main bearing caps 1 to 7.

Fig 1: Identifying Main Bearing Cap Number

Courtesy of BMW OF NORTH AMERICA, INC.

All numbers must be read from the cylinder bank (7 to 12) (see arrows in illustration).

Installation: 

All bearing caps are numbered 1 to 6.

The bearing cap on bearing seat 7 has no number.

Main bearing caps 1 to 7 on the output end on the timing chain drive.

Release oil pump spacer bolts (1) with special tool 13 5 020 .

Fig 2: Identifying Oil Pump Spacer Bolts

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 3: Identifying Main Bearing Taper Screw Releasing Sequence

Courtesy of BMW OF NORTH AMERICA, INC.

Release main bearing taper screw mounting from 1 to 11.

Release all thread support bushings (1).

Fig 4: Identifying Thread Support Bushings

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 5: Identifying Main Bearing Caps Collar Bolts (M8) Releasing Sequence

Courtesy of BMW OF NORTH AMERICA, INC.

Release collar bolts (M8) in sequence 1 to 14.

Fig 6: Identifying Main Bearing Caps Collar Bolts (M11) Releasing Sequence

Courtesy of BMW OF NORTH AMERICA, INC.

Release collar bolts (M11) in sequence 11 to 14.

Remove main bearing caps 1 to 7.

Lift out crankshaft and set down safely (secure against turning).

Release screw for oil nozzle (1).

Tightening torque: see 7AZ in 11 11 ENGINE BLOCK

Fig 7: Identifying Oil Nozzle With Screw

Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Check oil nozzle for clear passage with compressed air.

Observe fastening on oil nozzle.

Replace all O-rings.

Fig 8: Identifying Oil Nozzle O-Ring

Courtesy of BMW OF NORTH AMERICA, INC.

Replace MAIN CRANKSHAFT BEARING SHELLS .

Install crankshaft.

Installation: 

Observe arrangement of main bearing caps (1).

All numbers must be read from the cylinder bank (7 to 12) (see arrows in illustration).

Turn back all thread support bushings hand-tight.

The main bearing cap number 1 is on the timing chain drive.

Installation: 

Coat all main bearing points with engine oil.

Fig 9: Identifying Main Bearing Cap Number

Courtesy of BMW OF NORTH AMERICA, INC.

Fit main bearing caps (1 to 7).

Installation: 

For a better overview of the screw connection quality, mark the head of all collar bolts after joining with a line (1) using an oil-proof marker pen.

For more accurately checking entire angle adjustment.

Fig 10: Identifying Mark On Head Of Collar Bolts

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 11: Crankshaft Bolts Tightening/Loosening Sequence

Courtesy of BMW OF NORTH AMERICA, INC.

Insert collar bolts (M11) hand-tight in sequence (1 to 14).

(M11) Connect collar bolts in sequence (1-14) with 20 Nm torque.

To better check the total angular adjustment, mark all collar bolts M 11 with an oil-proof marker.

Secure collar bolts (M11) in sequence (1 to 14).

Fig 12: Tightening Main Bearing Caps Collar Bolts Using Special Tool 00 9 120

Courtesy of BMW OF NORTH AMERICA, INC.

Secure collar bolt (1) with special tool 00 9 120 .

Tightening torque: see 1AZ in 11 11 ENGINE BLOCK

Fig 13: Identifying Collar Bolts Inserting Sequence

Courtesy of BMW OF NORTH AMERICA, INC.

Insert collar bolts (1 to M8) hand-tight in sequence.

(M8) Connect collar bolts in sequence (1-14) with 10 Nm torque.

To better check the total angular adjustment, mark all collar bolts with a line using an oil-proof marker. M8

Secure collar bolts (M8) in sequence (1 to 14).

Secure collar bolt (1) with special tool 00 9 120 .

Tightening torque: see 2AZ in 11 11 ENGINE BLOCK

Fig 14: Securing Collar Bolt Using Special Tool 00 9 120

Courtesy of BMW OF NORTH AMERICA, INC.

Secure all threaded support sleeves (1) with special tool 11 4 350 .

Fig 15: Securing Threaded Support Sleeves Using Special Tool 11 4 350

Courtesy of BMW OF NORTH AMERICA, INC.

Tightening torque: see 3AZ in 11 11 ENGINE BLOCK

Tighten down main bearing taper screw mounting from 1 to 11.

Tightening torque: see 4AZ in 11 11 ENGINE BLOCK

Fig 16: Main Bearing Taper Screw Tightening/Loosening Sequence

Courtesy of BMW OF NORTH AMERICA, INC.

Tighten down oil pump spacer bolts (1) with special tool 13 5 020 .

Fig 17: Identifying Oil Pump Spacer Bolts

Courtesy of BMW OF NORTH AMERICA, INC.

Tightening torque: see 5AZ in 11 11 ENGINE BLOCK

Check crankshaft COEFFICIENT OF FRICTION .

Determine crankshaft breakaway torque  with special tool 00 2 010 .

Rotate crankshaft at central bolt using special tool 00 2 010 .

If the breakaway torque is too high, it will be necessary to correct the BEARING CLEARANCE .

Fig 18: Rotating Crankshaft Using Special Tool 00 2 010

Courtesy of BMW OF NORTH AMERICA, INC.

Secure special tool 11 6 252 to crankcase with magnetic base.

Slide crankshaft in direction of arrow forwards as far as it will go.

Set special tool 11 6 251 to zero.

Slide crankshaft (1) in direction of arrow towards rear and determine value.

Check AXIAL PLAY .

Assemble engine.