Timing Cover
When all the timing gear has been installed it is time for the timing cover to go back on. There are three seals in the cover- crankshaft, camshaft and the seal for the tacho drive cable.
The three seals can be replaced and tapped into place with a socket. I pre-stretched the cam shaft seal on the camshaft so that the lip would take the shape of the cam.
To replace the new gasket, I used a very fine smear of Hylomar blue to hold it in place. I have seen some advocate using an adhesive and others saying install dry. Either way, be sure not to forget the two small round gaskets around the upper corner bolts. Without these small gaskets, torquing the upper bolts would cause a slight tilt on the cover and likely cause leaking at the bottom.
When the new seals and gasket are in place, heat the central area of the cover where the crankshaft nose bearing will sit. Then the cover should gently tap into place with a plastic mallet.
With the cover in place replace all the fasteners in the same way as removal and tighten them in a crosswise sequence.
Alternator
The brushes and springs of the alternator were replaced. I used the replacement brushes with the eyes which allow them to be bolted into place, as opposed to the loose wires which require soldering in place. This was very easy.
First the rotor is replaced and the central bolt torqued to spec. Then the stator with the new brushes can be replaced, using a small flat screw driver or feeler gauge to hold the brushes out of the way.
Ignition points
Given the issues with the camshaft I destroyed and my general newfound paranoia about how easy the tips are to bend, I decided to measure the camtip runout prior to installing the timing points. The timing shaft is essentially a small cam itself with two high lobes which open the points twice per revolution. If the cam tip is bent slightly it will effect this rhythm and make getting the ignition timing right tricky.
To measure the runout I set up a dial indicator clamped to the crankcase and turned the engine over by hand using an allen key in the crankshaft. The BMW workshop manual states that the maximum permitted runout is 0.02mm (which is pretty small!) Luckily my measured runout was exactly 0.02 and I decided to leave it at that. I have heard of people gently tapping the shaft back into alignment with jeweller’s mallets if there is excessive runout but I have also heard of people breaker their cam tips off trying to do this so… 0.02 will be OK for me!
I replaced the points and the rubber sleeve they run in. The timing plate is screwed back in to the cover and then the points plate is installed. Make sure the lower screw secures the little bracket which routes the wire away from the cam tip. Hold the points out of the way and install the advance rotor onto the camshaft until the rotor engages the d-shaped notch on the camtip. Snug the nut down on a washer, not tight (4-5Nm) as it is very easy to bend the tip. The rubber sealing strip in the groove can be replaced- the new strip needs to have some glue applied and then be pushed into the groove.
Diode Board and Condensor
These were replaced as they were removed and everything wired together. This is where you will be glad for all those photos you took during disassembly!
