[urq] alternator whine puzzle (X post) long

Mon Oct 30 11:58:28 EST 2006

Brandon,

Have you tried disconnecting the + ign lead to the regulator such that it is
not charging? This will separate mechanical whine from charging.

Bernie

> From: "Brandon Rogers" <brogers at terrix.com>
> Organization: Terrix Financial Corporation
> Reply-To: brogers at terrix.com
> Date: Mon, 30 Oct 2006 09:42:33 -0700
> To: "'j.koenig'" <j.koenig at adelphia.net>, <urq at audifans.com>
> Cc: quattro at audifans.com, 200q20v at audifans.com
> Subject: RE: [urq] alternator whine puzzle (X post) long
> 
> Guys-
> Based on my tests so far - I'm starting to think this (John Koenigs
> response just below) may have some merit here.  I loosened the belt
> further over the weekend and it made no real difference that I could
> tell.  I would think a looser belt would make the sound go away some if
> it were alignment - as the stress would decrease.
> 
> So lets talk about charging.
> 
> My battery cable, which originally went straight to the alternator, with
> a "branch" to the starter, is now different because the alternator is on
> the other side and the battery cable will not reach.  The battery cable,
> BTW, is from a 200 20V.  So now the battery cable exits the frame rail
> and goes to the starter directly and a new, longer, "branch" goes over
> to the alternator.  According to my gauge, I'm seeing about 12.3V at
> night with lights on, about 12.9 to 13V during daytime.  Remember I've
> tried 3 separate alternators and the output has been consistent too.
> Any input on the charging wiring aspect that I should check? Is there a
> way to add a secondary ground strap?  Is the alternator working overtime
> hence the whine?  What would cause this?  Voltage Reg? Wiring? Anything?
> Anyone anyone?  Bueller bueller.
> 
> Thanks again
> 
> Brandon
> '84 urquattro 20Vt
> '01.5 S4
> '98 A4 1.8Tq
> 
> 
> -----Original Message-----
> From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
> Behalf Of j.koenig
> Sent: Thursday, October 26, 2006 6:11 AM
> To: urq at audifans.com
> Subject: Re: [urq] alternator whine puzzle (X post) long
> 
> 
> I'm no electrical engineer, and this may sound crazy, but I seem to
> remember something
> from years back about alternator "whine" issues being electrical rather
> than mechanical --
> something about improperly connected diodes or some such.  I'm sorry I
> can't be any more
> specific, but you might try looking at mounting/connecting/grounding
> issues, since they
> all do it, you have changed the game, and you can't identify any
> mechanical cause. Good luck. John
> 
> 
> ----- Original Message -----
> From: "Brandon Rogers" <brogers at terrix.com>
> To: <urq at audifans.com>; <quattro at audifans.com>; <200q20v at audifans.com>
> Sent: Wednesday, October 25, 2006 6:31 PM
> Subject: [urq] 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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