[T2] more on early alternator

[Robert Mann]

     The slip rings are so worn that the copper on them is foil-thin and
indeed absent for approx 1/4 of their circumference.  I suspect a couple
turns of copper foil could be a medium-term cheap fix; but in the spirit of
reckless experimentation we sprayed graphite dust (sold for locks) on the
worn copper tracks.  We see some hope in the much thicker copper
'shoulders' of the slip rings  –  perhaps the brushes touch them enough to
conduct  ...  ?
     BTW the brushes look from a distance like oblong carbon, as in the old
generators, but turn out to be layers of metal.
     The regulator, internal in contrast with other Bosch alternators which
have an extl reg on the firewall, in my case is a dark-brown plastic box
proudly marked Made in Australia; I suspect Bosch had a factory in that
country and were able/required to buy some parts locally.
      The number & sequence of washers along the fan-alternator shaft must
be carefully restored.  But even then, the total thickness they embody can
go astray: the wavy washer under the 36mm nut holding on the fan is capable
of fitting incompletely, skewed, over the "oblong"-section shaft.  When the
rearmost nut (rear end of the alternator) of that shaft is then tightened
with the light of victory in the eye, that nut can be a couple turns less
far 'on'; this is the tipoff that the fan will then scrape the shroud
because it is not straight on the shaft because the wavy washer is not on
straight.  Mirrors or a midget 'TV' camera can help in pushing the wavy
washer fully on that oblong shaft –  the shaft is *not *bilaterally
symmetrical, so the wavy washer can fit only 1 way, not  'either of 2 ways,
180° apart'.

     Again I hold forth in annoyance & puzzlement if not contempt at the
perverse *die Kräute* who persisted in making the fwd 2 of the 4 alternator
stand hold-down studs exasperatingly difficult to access with ordinary
tools.  The same is true, as earlier remarked, of the lower 2 cheese-head
screws retaining the rear 'sealing' tin sheet (dia. c. 10") between the
alternator and its shroud.  Anthony has cautiously mentioned he leaves out
the lower-R of those monsters; the lower-L is IMHO even worse.  Why were
these holes not relocated to allow much readier access?  Anyhow, we've left
off both those lower screws, leaving only the upper 2 clamping that tin
'seal' sheet.  My guess is that air for cooling the engine will not be
seriously diverted.  Perhaps an eerie whistle will be produced at speed by
small air leaks??  Anyhow we notice not far away in the rear wall of the
shroud a couple of official-looking round holes dia. c.1 cm which would
leak far more air than the slit round the lower edge of that 'seal' sheet.

    When we got it all together and spinning the alternator by hand evoked
no untoward noises, I then slapped a half-eggcup of Tergolite® straight
down the carb (having no gasoline on hand) and started the engine.  The
good news was that the discharge warning light went off at moderate revs,
and STAYED off when back down at idle; a DVM across the battery during this
test read 13.8 V.  However, a nasty loud tinny noise was all too apparent.
With great relief we soon discovered this was due to a small spanner which
had fallen into the 'black hole' tin ditch in which the crankshaft pulley
runs.  I assume it's only us 'upright' motor owners who harbour this trap;
the Typ4 motor hasn't, I believe.

    The remaining Q is how long the severely worn slip rings will now
last.  We'll take a charger to bludge electricity from our respective hosts
on our imminent Spring tour of the Far North.

     Thanx for help in this exploration.  Will report on the future of the
slip rings.


Robt Mann
'73 1600dp Devon