Slide the pulley onto the toe of the crankshaft without tightening the pulley mounting nut. Set the piston of the 1st cylinder to the TDC position at the end of the compression stroke. In this case, the TDC mark on the pulley should be opposite the pointer (models «518», «520») or high tide (models «525», «528») on the bottom cover of the timing gear drive. Ensure this when installing the timing cover.
Insert the chain into the damper and put it on the crankshaft sprocket in accordance with the alignment mark applied to the chain when it was removed.
Wire the two branches of the chain at the top of the damper.
Install the lower timing cover gasket and apply Atmosit type sealing paste to the lower mating surface of the cover.
Remove the crankshaft pulley without turning the shaft, then install the lower timing cover.
After assembling the heads of the cylinders (cm. «Cylinder head assembly») install the camshaft flange with the dowel pin pointing down. In this case, the risk on the flange (models «518», «520») must align with the alignment lug on the cylinder head (see photo in subsection «Installing the cylinder head»). On models «525» And «528» flange dowel must be» shifted at an angle of about 45°downwards and to the left.
The top threaded hole must align with the alignment lug on the cylinder head (see picture).
Place a dry gasket on the cylinder head studs (gasket can only be installed in one position). Install the cylinder head. Tighten the mounting bolts in three steps in the prescribed manner (see above).
Separate the branches of the chain and put it on the camshaft sprocket, aligning the holes in the pulley and in the camshaft flange (models «518», «520»).
Tighten the camshaft sprocket mounting bolts and lock them by bending the locking plates.
Pour engine oil into the groove of the upper timing cover to the level of the chain tensioner plunger. Bleed the chain tensioner as follows:
- install the plunger and tensioner spring; in this case, it is necessary to insert the front groove of the plunger into the bracket of the tensioner shoe and direct the spring with the conical part to the plug;
- partially wrap the tensioner plug;
- press several times with a screwdriver on the tensioner shoe bracket until oil groans from the plug;
- wipe off the plug and screw it back on.
Note. Causes of noisy camshaft drive circuit can be air in the plunger, stuck plunger, clogged plunger vent slots, ball valve failure, excessive stiffness or weakening of the plunger spring, stuck chain tensioner shoe bracket.
Install the timing gear top cover. having previously applied Atmosit type sealant to its lower part.
Install the ignition distributor bracket. Install the ignition distributor in such a position that the rotor is against the mark on the distributor housing, and the piston of the 1st cylinder is at TDC of the end of the compression stroke.
Insert segment keys into sockets at the front end of the crankshaft, press in a new crankshaft front oil seal. Install the crankshaft pulley and secure it with a nut with a washer, tightening it with a torque of 14.0-15.0 kgf·m.
Install the clutch with the driven plate protruding towards the pressure plate and center the disc relative to the flywheel with a mandrel.
Adjust the clearances in the valve drive Install the removed components and assemblies on the engine.
Stop the engine (or power unit) and install it on the car.
From model year 1978 disassembly and assembly of engines «525», «528» And «528i» produced according to the following:
- when replacing the camshaft drive chain: remove the cover of the ignition distributor; put the piston of the 1st cylinder in the TDC position, aligning the mark «FROM» on the vibration damper with a mark on the bottom cover of the timing mechanism drive; in this case, the speed limiter must be directed to the risk on the ignition distributor housing;
- when replacing the crankshaft sprocket: remove the camshaft drive chain, oil sump, oil pump drive sprocket; remove the segment key and remove the oil seal from the crankshaft sprocket; press the sprocket with puller 112000; replace the camshaft drive chain and oil pump drive chain;
- when replacing the rocker shafts: after removing the screw plugs, screw in special tool 113060 (before 7004); remove the mounting studs, press out the axles of the front valve rockers; installation is carried out in the following order: spring 3 (see photo), washer 4, rocker arm 5, thrust ring 6;
- when replacing rocker arms: install calibrated screw 1 (see photo), eccentric 2, washer 3 and nut 4 on a new rocker arm. If the eccentric is worn out, replace it.
Note. The calibrated screw and nut have M6x0.75 thread. The flat of the calibrated screw should be directed towards the back of the rocker arm.