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Noise from new alternator

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RobWarren

Jedi Hopeful
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Righto.

Neg earth conversion complete and a new shiny alternator installed. I'm happy with everything except for the noise:

I'm getting a whirring noise when idling. The second I apply any revs to the engine, the whirring goes away but comes back as soon as the clutch is engaged. Without the benefit of someone to goose the throttle while I've got my nose under the bonnet, I am assuming that this noise is being created by the new pulley/ wheel on the alternator and the belt.

I know that the wheel the alternator came with was removed and a replacement put on that extended outwards a couple of inches to achieve the necessary clearance - is this likely to be the cause?

Is the noise likely to go away with wear/ running in or should I apply some dry lube. Worse still - how do I tell if it's the alternator bearings?

Your expertise as ever, is most welcome.

Bob
 
Not an expert here but I'm confused by the extension you're talking about. I didn't need any extension for my alternator kit. Mine came from Hendrix Wire Wheel. The extension could put a weird load on the bearing of the alternator and I think that would shorten the life span. Engaging the clutch causing the noise sounds like a worn throw-out bearing to me.

Here is a photo of my alt installed. I replaced the pulley with a larger grooved one, but it has the same alignment as the one pictured.
 

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Bob,
I'm also confused. Is the whirring related to clutch engaged/disengaged or to engine rpm?

A frequent cause of alternator "whine" is a shorted diode internal to the alternator. It would be related more to alternator speed & load, than anything to do with the clutch. Also a noisy alternator bearing can make a strange sound.

A wood stick placed one end on the alternator, the other end to your ear could help localize the sound.

You should be able to "goose the throttle" from under the hood by manually pulling the throttle linkage.
D
 
Sounds to me like your throwout bearing or clutch cover ring has come loose. Doesn't sound like anything to do with your Alt.
 
Dave, i think what hes trying to tell us is that when he engages the clutch causing = a lower r.p.m. slower rotation of the alt. the noise reappears, his clutch has nothing to do with his problem. hes probably just got a slight misalignment of the alt./ belt not adjusted properly etc. :savewave:
 
Sorry fellas, I obviously didn't explain myself very well - and I'll do a bit more fact-finding to see if I can figure out the problem myself.

The alternator I had installed was done so requiring further clearance (and inch or so) so it's as if the pulley wheel is on a prod and I think it must be this that is perhaps a touch mis-aligned.

The whirring/ fan noise however, only occurs when idling. it's this that is confusing me.
 
Hi Rob,
The need for an extension shaft still has me baffled. You might start with Anthony's suggestion on alignment by placing a straight edge across the pulleys. Maybe belt tension is too tight?
 
No noise before alt change out only after kinds of narrows it down, fan on alt front wasnt fitted on backwards after mods?
 
Will check and get back to you blokes after the weekend (next time I get to have a play!)

From memory (which is dreadful at the very best of times), there is no fan on the alternator wheel - but I'll check.
 
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