alternator whine puzzle (X post) long

[Geraint Lloyd]

Brandon,

You seem to be looking for 'oddball suggestions' so
here's my musings

I know that it's fraught with danger, but have you
been under the car
with the engine running?
perhaps you could use a stick as a stethoscope to find
out where the
noise is coming from
i suppose that your ac compressor may be in the way
though.
you tried running with no alternator, but have you
tried  running with
with just the alternator in its current position and
no AC?
maybe it's a combination of the 2

Just a thought, but the AC pulley and the old
alternator pulley on the
crank are the same size are they.
there is not some bizarre gearing issue going on is
there?..... I can't
really see how that would make a difference though


are the original alternator and AC belts the same
width? or are you  now
using a different part of the alternator pulley /
trying to squeeze a
fat belt in a thin V?

as I said, just some ideas


Geraint




Brandon Rogers wrote:
> 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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>
>
>   

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