Checking main bearing clearance

To check crankshaft bearing clearance, use the existing main bearing screws.

No oil is permitted in the blind bores.

Do not twist crankshaft.

Place special tool 00 2 590 (Plastigage type PG 1) on oil-free crankshaft (see arrow in illustration).

Fig 1: Checking Main Bearing Clearance

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 2: Main Bearing Cap Collar Bolts Tightening/Loosening Sequence

Courtesy of BMW OF NORTH AMERICA, INC.

Tighten down all collar bolts (M11) of main bearing caps in sequence 1 to 7 to jointing torque.

Tightening torque: see 1AZ in 11 11 ENGINE BLOCK

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

Fig 3: Tightening Main Bearing Caps Collar Bolts Using Special Tool 00 9 120

Courtesy of BMW OF NORTH AMERICA, INC.

Remove main bearing cap.

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

Main bearing play: see RADIAL CONROD BEARING PLAY , CRANKSHAFT AXIAL PLAY , BEARING JOURNAL 1 , and BEARING JOURNALS 2-7 .

• Remove plastic thread
• Apply a coat of oil to new bearing shells and crankshaft
Fig 4: Measuring Main Bearing Play Using Measurement Scale
Courtesy of BMW OF NORTH AMERICA, INC.

Do not wash off bolt coating.

No oil is permitted in the blind bores.

Install CRANKSHAFT .

Carefully strike back and front of crankshaft (1) 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 of crankshaft and crankcase.

Fig 5: Checking Crankshaft Axial Play

Courtesy of BMW OF NORTH AMERICA, INC.

Check AXIAL PLAY.

Assemble engine.