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TR6 altenator (Lucas 15-ACR) reassembly (longish)

To: triumphs@autox.team.net, <6pack@autox.team.net>
Subject: TR6 altenator (Lucas 15-ACR) reassembly (longish)
From: Cregg Cowan <cowan@erg.sri.com>
Date: Tue, 14 May 2002 14:47:50 -0700
Hi Triumph enthusiasts,

I'm having trouble re-assembling the alternator from my (sort of) daily 
driver 71 TR6.  It is one of the old 5-wire types.

The alternator was working but making a whirring noise, which I assumed to 
be the front bearing. I was encouraged by the article at 
http://www.vtr.org/maintain/alternator-repair.html and found an inexpensive 
source for the bearings (NTN 6202ZZ) at
http://www.arrowweb.com/bake/home.htm

Unfortunately, both bearings were making noise but I had ordered two just 
in case.  I replaced them both, re-soldered the slip ring and was feeling 
pretty good until I assembled the front (pully end), windings (stator?) and 
rear (rectifier end) and noticed something was rubbing inside the case.

After much examination the problem may be that the case goes together too 
far (hard to explain).  That is, if I don't tighten the 3 machine screws 
(which hold the front and back together), leaving them loose by ~1/8 inch, 
then the rotor turns smooth as silk (as you'd expect with new 
bearings).  Unfortunately, everything (front, windings and rear) is still 
loose without the screws tightened.  When I tighten the screws, a plastic 
"spacer" between the rotor and the rear bearing (which protects the wires 
to the slip ring) rubs against the inside of the rear casing.

OTOH, I had difficulty in removing the rear bearing and tried to remove it 
by prying on the bearing while tapping the rotor shaft with a hammer.  The 
rotor was supported by the jaws of a bench vise at the time and so the 
rotor *could* have moved on the shaft, but I see no signs of 
it.  Furthermore, I tried to reverse the process ;-) by hitting the other 
end of the shaft with no noticeable effect.

Now, finally, the question(s):

        1. What is supposed to keep the plastic spacer from rubbing the case?
        2. Should the rear bearing be the same as the front one?  The one I 
removed was indeed an NTN 6202ZZ, but who knows what happened on some 
previous rebuild.
        3. Is there a locating mark on the rotor shaft?  How can I verify the 
rotor is in the correct location.

I know I could more replace the Lucas unit with a reliable Delco or Bosch, 
but I am loath to admit defeat at this point.

Regards and TIA,
Cregg Cowan
71 TR6

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