Disassembly and assembly of the engine (BMW 3 Series E21)

Disassembly

Place the washed and cleaned engine on a rotating stand for disassembly.

Remove the intake and exhaust manifolds.

Remove the ignition distributor sensor and fuel pump.

Remove the TDC sensor, alternator drive belt, pulley and alternator.

Remove the cylinder head as described above.

Remove the oil pan.

Remove the vibration damper from the hub.



Lock the crankshaft from turning with key 11 2 150.

Loosen the vibration damper hub mounting bolt and press it off, for example, using the Kukko puller 00 7 501 with threaded pins 11 2 132.

Remove the camshaft drive belt and press off the crankshaft toothed pulley, for example using the Kukko puller 00 7 501 with grub screws 11 2 131.



Lock the intermediate shaft pulley with a 11 2 190 wrench, unscrew its mounting bolt and remove the washer.



Remove the intermediate shaft pulley.



Remove the front cylinder block cover.

Disconnect the clutch housing from the flywheel.

Measure the axial free play of the crankshaft using an indicator.

Remove the flywheel, then remove the crankshaft rear oil seal retainer.

Check the markings on the connecting rod caps (the covers are counted from the camshaft drive side). Loosen the connecting rod bolt nuts, remove the connecting rod caps and lower connecting rod bearing shells and put them in order.

Mark the main bearing caps, remove them along with the lower bearing shells and put them in order.

Remove the crankshaft from the bearing seats.

Press out the needle bearing using puller 11 2 010.

Assembly

New crankshafts are marked at the factory with red or blue paint on the side surfaces of the counterweights. Crankshafts with ground journals are marked with paint on the main and connecting rod journals: one color line corresponds to the 1st repair size, two color lines indicate the 2nd repair size.

Warning: The crankshaft has undergone special treatment and may only be ground in factory conditions.

Thoroughly clean the working surfaces of the crankshaft bearing shells and main journals. Place a piece of plastic calibrated wire type PGI on the journal surface. Install the main bearing cap on the journal and tighten the mounting bolts, preventing the crankshaft from turning. Remove the cap and, using the scale on the packaging and by flattening the wire, determine the clearance between the main journal and the shell.



Press the needle bearing into the rear flange of the crankshaft using a mandrel, directing the inscription on the bearing towards the flywheel and maintaining the pressing depth, which should be 5 mm.

Install the lower main bearing shells and place the crankshaft into the main bearings.

Install the main bearing caps, aligning the grooves on the liners.

Insert the pistons with connecting rods into the cylinders. Replace the connecting rod bolts each time the engine is disassembled.

Install the crankshaft rear oil seal retainer.

Install the flywheel. Check the crankshaft axial clearance and adjust it if necessary by replacing the 6th main bearing flange shells.





Install the oil pump.

Apply sealant such as Atmosit or Curil K 2 to the cylinder block at the locations of the mounting pins and to the corresponding surfaces of the oil pan.





Install the oil pan, then put the cylinder head back in place.

Install the clutch cover.