Checking main bearing clearance

To check crankshaft bearing play, use the existing main bearing bolts.

IMPORTANT: Risk of cracking!
No oil is permitted in the blind holes.

Do not twist crankshaft.

Place special tool 00 2 590

(Plastigage model PG 1) onto the oil-free crankshaft (see arrow).

Fig 1: Identifying Main Bearing Clearance On Crankshaft

Courtesy of BMW OF NORTH AMERICA, INC.

Tighten down all collar bolts (M11) of main bearing caps in sequence 1 to 5 to jointing torque.

Tightening torque 11 11 1AZ .

Fig 2: Main Bearing Cap Bolts Tightening/Loosening Sequence

Courtesy of BMW OF NORTH AMERICA, INC.

Tighten down all collar bolts (M11) of main bearing caps with special tool 00 9 120 with angle of rotation.

Fig 3: Tightening Collar Bolts (M11) Of Main Bearing Caps With Special Tool 00 9 120 With Angle Of Rotation

Courtesy of BMW OF NORTH AMERICA, INC.

Remove main bearing cap.

Read off main bearing clearance at width of flattened plastic thread with assistance of measurement scale.

Remove plastic thread
Apply a coat of oil to new bearing shells and crankshaft

Fig 4: Measuring Main Bearing Clearance
Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Always replace main bearing bolts in main bearing caps with new bolts.
Do not wash off bolt coating.

IMPORTANT: Risk of cracking!
No oil is permitted in the blind holes.

Carefully strike back and front of crankshaft with a plastic hammer to center guide bearing (do not damage crankshaft).

Secure special tool 11 6 252 with magnetic foot on crankcase.

Position special tool 11 6 251.

Tightening specifications for main bearing:

Check guide bearing shell, crankshaft and crankcase if necessary.

Fig 5: Checking Side Clearance

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.