Crankshaft & Main Bearings

NOTE: Engine is removed from vehicle for following procedure.

Remove lower timing case. See TIMING CASE LOWER SECTION under REMOVAL & INSTALLATION. Remove piston. See PISTON & ROD ASSEMBLY under REMOVAL & INSTALLATION. Remove flywheel. Remove rear end cover. Remove taper bolt mount on main bearing. See Fig 1 . Remove bolts securing main bearing caps. See Fig 2 . Remove main bearing caps 1-7. See Fig 3 . Lift out crankshaft.
NOTE: To check crankshaft bearing clearance, use old main bearing bolts. See Fig 4 .
Check bearing clearance on crankshaft. Install main bearings in engine block. Install Plastigage to oil-free crankshaft. See Fig 5 . Do not turn crankshaft. No oil is permitted in blind bores as there is a danger of cracking. Install main bearing cover and check main bearing clearance on width of Plastigage. See Fig 6 .

Fig 1: Removing Taper Bolt Mount
Courtesy of BMW OF NORTH AMERICA, INC.

Fig 2: Removing Main Bearing Cap Bolts
Courtesy of BMW OF NORTH AMERICA, INC.

Fig 3: Removal Sequence - Main Bearing Caps
Courtesy of BMW OF NORTH AMERICA, INC.

Fig 4: Checking Bearing Clearance On Crankshaft
Courtesy of BMW OF NORTH AMERICA, INC.

Fig 5: Identifying Plastigage
Courtesy of BMW OF NORTH AMERICA, INC.

Fig 6: Checking Width Of Plastigage
Courtesy of BMW OF NORTH AMERICA, INC.

Fig 7: Identifying Shaft Diameter Color Code - Bearing Thickness Survey
Courtesy of BMW OF NORTH AMERICA, INC.
Remove plastigage. Install main bearing cover on engine block and tighten bolts. See Fig 9 . If necessary, check guide bearings, crankshaft and engine block. See ENGINE SPECIFICATIONS . Check connecting rod bearing clearance. See Fig 10 . On each connecting rod, install one Red and one Blue connecting rod bearing shell. (Irrespective of color code on connecting rod shaft).
CAUTION: Note grinding stages on crankshaft.
Install piston. See PISTON RINGS . Place piston in TDC setting with Plastigage on oil-free crankshaft. Install connecting rod bearing cover so pair numbers match. See Fig 11 . When tightening connecting rod bolts, use Rotary Dial Angle Gauge (00 9 120). See Fig 12 . See TORQUE SPECIFICATIONS . Remove connecting rod bearing cover and read off connecting rod bearing clearance on width of plastigage. See Fig 13 .
For connecting rod bearing clearance, see CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECIFICATIONS . Remove plastigage. If necessary, remove chain wheel from crankshaft. Install Pressure Piece (11 2 383) to crankshaft. Install Bell (11 2 001) to Spindle (11 2 005) and Plate (11 2 006) to complete unit. Pull off sprocket wheel. See Fig 14 .

Fig 8: Shaft Diameter Color Code - Bearing Thickness Survey No. 2
Courtesy of BMW OF NORTH AMERICA, INC.
Shrink-fit chain wheel to crankshaft. Check wedge for correct position. Heat chain wheel to maximum 301°F (150° C) using hot air blower. Do not exceed specified temperature. Replace main bearings on crankshaft. Replace connecting rod bearings.