[urq] alternator whine puzzle (X post) long

[Ingo Rautenberg]

Are you sure the alternator (I don't care if it's been rebuilt) itself isn't
the problem?  If you reposition the alternator to the original location does
the noise go away?

Hoping you get to the root of the problem before you and us go INSANE!! ;-)

Ingo
----- Original Message ----- 
From: "Brandon Rogers" <brogers at terrix.com>
To: <urq at audifans.com>; <quattro at audifans.com>; <200q20v at audifans.com>
Sent: Friday, November 03, 2006 11:44 AM
Subject: Re: [urq] alternator whine puzzle (X post) long


> Latest update:
>
> I have driven the car with the voltage regulator removed - so the
> electrical charging theory has been eliminated.  A few nights back I
> loosened the alternator belt some (it was not ultra tight to begin with
> however) and the noise did not seem to change a whole lot - maybe a
> _little_ less loud - I would think that loosening the belt would
> decrease the sound quite a bit if the noise were caused by abnormal load
> on the bearings.  Another theory out there was related to having all 3
> accessory belts pulling on the same side of the motor.  My a/c belt was
> pretty darn tight - so last night I removed the a/c belt altogether and
> took a drive.  No real improvement.
>
> So the only thing that remains is 1) misaligned alternator due to
> bracket being "crooked" or 2) some how the bracket is flexing or
> something - but I don't see how this would cause the noise I hear
>
> Brandon
> '84 ur
>
> -----Original Message-----
> From: Brandon Rogers [mailto:brogers at terrix.com]
> Sent: Thursday, October 26, 2006 9:37 AM
> To: 'urq at audifans.com'; 'quattro at audifans.com'; '200q20v at audifans.com'
> Subject: RE: alternator whine puzzle (X post) long
>
>
> Guys-
> thanks for all the responses.  Jsut a coupel quick additional comments I
> left out - I have used several brand new belts of varying lengths and
> the alternator makes the noise regardless.  I probably have only about
> 10 miles on any particular setup I've tried so maybe the belt will "wear
> in" but it really is a mechanical sound.  Sounds to me like I need to
> really look at alignment in all planes.  I  have looked at that - but it
> sounds like I need to get the car higher higher off the ground than just
> ramps so I can get a better perspective.
>
> If I can't get this noise to go away I may have a plug and play 944T
> intercooler ( all modified and ready to hook up to factory turbo-IC
> (20V) and michelin man from IC to RR pressure pipe) for sale.  The noise
> as loud as it is right now ruins the experience of driving an I-5 turbo.
>
>
> Thanks again -
>
> any other ideas keep 'em coming-
>
> Brandon
>
> -----Original Message-----
> From: Brandon Rogers [mailto:brogers at terrix.com]
> Sent: Wednesday, October 25, 2006 4:31 PM
> To: 'urq at audifans.com'; 'quattro at audifans.com'; '200q20v at audifans.com'
> Subject: alternator whine puzzle (X post) long
>
>
> OK Guys -
> here is a frustrating one - bear with me.  Subject is an '84 urquattro
> with 3B 20Vt motor.  The car still has a/c, the stock urq unit which is
> a mini-York mounted on the driver side.  I recently installed a larger
> intercooler from a 944 turbo.  This necessitated moving the alternator
> from the stock location on the urq (on the passenger side) to the driver
> side.  Most people who do this ditch a/c, but as noted I did not and
> don't want to.  2Bennett makes a bracket (steel I think) that mounts the
> alternator to the underside of the urquattro a/c compressor, allowing
> for extra room on the passenger side for a big intercooler.
>
> So I got the bracket, got hold of the proper alternator (thanks to
> another Lister who had one in his basement collecting dust).  I mounted
> it up, it charged fine, but it whined.  As revs would climb the whine
> would get louder - loud enough to almost drown out a 20Vt with a test
> pipe and no center resonator.  At idle, no noise.  Off the car,
> alternator spun like butter.  But I figured a bearing was going bad due
> to the noise.  Had new bearings installed - rebuilder did call me, BTW,
> to tell me the unit worked fine but I told them to replace the bearings.
> Reinstalled alternator.  No real difference - still whined.  Hmmmm.
> Checked belt tension but this is clearly a mechanical whine.  Verifed by
> another Lister later in this process.  So I drove the car WITHOUT the
> alternator. No whine.  Okay good - must be the alternator.  Reinstall
> alternator without voltage regulator.  Whines like before - ok gotta be
> bearings.  So I went to a local salvage yard and got another used
> alternator.  Mounted it - ran the car.  Whined like the other one.  Okay
> could this be coincidence - 2 alternators with bad bearings?
>
> So I checked the alignment of the alternator to the pulley - seemed
> maybe slightly off so I took a grinder to one of the holes to line it up
> best I could tell.  No real difference - still whined.
>
> So I took the car back to the place that rebuilt the alternator - had a
> guy ride with me to hear the noise.  He said it didn't necessarily sound
> like bad bearings, but I informed him there is no noise with no
> alternator.  His rebuilder said she has seen one or two over 20+ years
> make noise and need a new body.  Told me to take it off and bring back
> and they would rebuild and swap bodies - and since I had two alternators
> I could provide another body - problem of course being both of those
> units whined - so I was still a little hesitant.
>
> Just to experiment, in case there was some sort of harmonic resonance
> occuring or something??? I then installed a rubber sheet gasket between
> the contact areas of the 2Bennett alternator bracket (it is a plate with
> tabs hanging down) and the stock a/c compressor bracket.  This made
> virtually no difference.
>
> As luck would have it - another lister also had an alternator I could
> try.  Well it whines too!  So 3 separate alternators whine.  I did take
> the car out again prior to instal of alternator #3 to make sure the
> whine was gone with no alternator.  This was the case.
>
> ACKKKKKK!!!  How could a bracket or alternator placement make 3 separate
> alternators whine!?!?!?  I talked to 2Bennett today and Andrew Bennett
> said he's never heard of this.  That said, Andrew Finney had one of
> these on his car and he did tell me his alternator was a little louder.
> At this point I've asked 2B to send me a new one and I then send this
> one back - hopefully they will follow through.
>
> But more important - any idea what the heck could be going on??????
>
> ANY input appreciated.
>
> Thanks for reading - I'm currently not receiving mail mail from the
> "mother List" so if you reply from there please cc me - thanks!
>
> Brandon
> '84 urquattro 20Vt
> '01.5 S4
> '98 A4 1.8Tq
>
>
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