Conrod with M10x1.25 conrod bolt:

If a new set of conrods has been installed: use the conrod bolts used in the new set of conrods. If the conrods already used have been installed: install new conrod bolts. See Figure .

First tightening of conrod bolts: 

Tighten down conrod bolts with special tool 00 9 120. Tightening torque:

• Application torque 5 Nm
• Joining torque 30 Nm
• Angle of rotation 105°

Fig 1: Tightening Conrod Bolts

Courtesy of BMW OF NORTH AMERICA, INC.

Remove bearing caps. Read off bearing clearance at width of crushed plastic thread with aid of measuring scale. Conrod bearing clearance: 0.030 to 0.070 mm.

Fig 2: Measuring Bearing Clearance

Courtesy of BMW OF NORTH AMERICA, INC.

• Remove plastic thread.
• Coat crankshaft and bearing shells with oil.
• Fit bearing caps so that the pair numbers match up.
• Fit the conrod bolts used for the bearing clearance.

Second tightening of conrod bolts: 

Tighten down conrod bolts with special tool 00 9 120. Tightening torque:

• Application torque 5 Nm
• Joining torque 30 Nm
• Angle of rotation 105°

If a new set of conrods has been installed: 

The conrod bolts must not be tightened down again as they have already been screwed down three times when the conrod was machined and have reached their maximum tensile strength.

If the conrods are reused and only the conrod bolts have been replaced: 

The conrod bolts must be slackened again and brought to maximum tensile strength by the third tightening operation. If the conrod bolts have not been tightened at least three times or have been tightened more than five times, this will result in serious engine damage.

If necessary, back off conrod bolts by approx. one turn.

Third tightening of conrod bolts: 

Tightening torque:

• Application torque 5 Nm
• Joining torque 30 Nm
• Angle of rotation 105°

Install spray nozzles for piston cooling, tighten down screw. See Figure . Tightening torque, 11 11 7AZ. Refer to 11 11 ENGINE BLOCK .