Might be time for an alternator

[The Veg]

Seems like my car's voltmeter sometimes shows strange things...like the needle dropping when the engine picks up speed, despite no accessories being in use.

Tonight I was tinkering after dark and when I tugged on the throttle cable I saw some bright orange sparks coming from around the front of the alternator, much like you see when using the cut-off wheel in a rotary tool.

Could these things be related? :hrhr:

[lotus4s]

Naw, I wouldn't worry about the special effects lighting....

Do you also have the special brown goo dripping on your ac compressor?

[The Veg]

No goo YET...but with something rubbing enough to make sparks, I ain't gonna wait around for no steenkin' goo!

[molemot]

Might be the cambelt tensioner...ought to have an earthing strap on it; otherwise it and the cambelt become a Van der Graaf generator and produce very high voltage static electric charge, which has to discharge to earth producing just the sort of display you describe!! And yes, it could be the alternator....but that'll only be low voltage and thus not give much in the way of a spark gap.

[s2mikey]

Sounds like it is time for some new electricity

[The Veg]

Might be the cambelt tensioner...ought to have an earthing strap on it; otherwise it and the cambelt become a Van der Graaf generator and produce very high voltage static electric charge, which has to discharge to earth producing just the sort of display you describe!! And yes, it could be the alternator....but that'll only be low voltage and thus not give much in the way of a spark gap.

The sparks diverge outward as they shoot downward from the front of the alternator, and in a direction and pattern that agrees with the alternator's direction of rotation, so I doubt that it's the cambelt tensioner. Also, they look like the kind of bright orange sparks you get when you grind steel. I'm guessing that the pulley is making contact somewhere, and/or the alternator's front bearing has a problem...but even if I'm totally incorrect, it needs to come out for closer inspection. I'm going to buy a replacement just in case- I can always return it to the store if it's not needed.

Sounds like it is time for some new electricity

Or maybe...

Edited September 27, 2011 by The Veg

[The Veg]

UPDATE:

I've got the alternator out, and I'm not sure about the source of the sparks. No overt signs of rubbing or friction, and the shaft has no excessive end- or side-play and spins freely. Hmmm.

However, I spoke too soon about the goo.

None had dripped onto the compressor, but once the alternator was out I thought I saw a slight sheen around the gap between the metal body and the plastic cover over the rectifier. I popped off the cover and it was hard to find, but a very slight, thin trickle of black goo is just starting to come from behind the rectifier.

I never liked Valeo products anyway, beginning with the starters they supplied for BMW motorcycles. Those had a tendency to lunch themselves when the magnets came unglued(!). I'll be making calls for a Bosch unit tomorrow.

[Iconic Ride]

Good one, Ben. The Lucas tradition continues unabated.

Good luck with the alternator issue. Hey, what's the worst thing that could happen? Ten batteries in the boot and a cockpit rotary selector?

[The Veg]

'NUTHER UPDATE:

I knew that there were multiple Bosch units that could work and that the AL-49X was a popular choice, but a little digging around revealed that the AL-299 (P/N 14786 at Advance or AutoZone) is one of the most brilliant choices: 90 amps, no need to rotate half the housing, just swap the pulleys, drill out a mounting hole and drop it in, and *UNDER $100!*

Got that in and the voltmeter now does something it has never done in the 11 months that I've owned the car: it stays above 13V no matter what load of accessories I turn on!

[Iconic Ride]