I am also looking at replacing my altenator as it is a LUCAS one.Not so much amps that it puts out.
All you guys are talking about weird cars that we don't get here in South Africa.

Except for Quote: written by b310gx. Is this a Nissan car?

i used the alternator off a Z24 from a navara, it's internally regulated & has a larger pulley on it than the standard one. This slowed the alternator down, which was important as it was a race engine.this meant the alternator did not burn out. Went straight onto the later a series alternator casting & the alternator arm lined up too. No grinders needed.

i run an internaly regulated xf falcon alternator, 1 hour job to cut down bracket with a hack saw or 2 mins with an angle grinder to make it fit, pulley is at the right spot to, in line with the other 2

Quote:

What model sigma? Or are they all the same?

I've had the brushes in the alternator wear out twice.
The charge light came on intermittently when this happened.

No the alternator light does not come on, and it was a new wiring loom about 10 yeras ago, but I'bve only travelled about 20,000klm or 8,000 miles so it may not be the wiring, but I will check and I will check out the regulator as well, thanks guys for all the tips!
Oli

11 volts is too low. A properly working charging system must be 13.5 to 15 volts when engine is running above 1200 rpm or os.

Now the problem is usually one of two things:
* Alternator (less often)
* Regulator (more often)
Don't pay money for a new alternator when it is more often just the regulator.

Less like it could be bad wiring. Check the voltage at the alternator, not at the battery. If it is 14V there, but only 11V at the battery, you have bad wiring.

sometimes the piece of wire to the battery gets old and crappy and causes the battery to not charge too...


does the alternator light come on?

Well I have not had it profesionally Checked yet, but on my VOLT Gauge, it only reads about 11 - 11 1/2 volts, but the two times it has failed me was :
1) Driving at night with lights on. ( Quartz Halogen )
2) Hot day with electric fan on, there's no engine fan.
So I am assuming it is not charging enough voltage to run these electric items and the power is coming directly outr of the battery.

a good thing to check is how much AC voltage you have at the battery, that will give info on what is going wrong... in bad cases you can see 15 volts of AC at the battery which would be an indication of diodes in the alternator being fried...