Date: Tue, 23 Aug 2005 06:01:39 -0400
Reply-To: Ken Wilford <kenwilfy@COMCAST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ken Wilford <kenwilfy@COMCAST.NET>
Subject: woodruff key or not woodruff key that is the question
In-Reply-To: <1db.423b3fa6.303bcdf5@aol.com>
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I have taken the fan assembly off of thirty or fourty Vanagon
alternators over the years. Most of them (probably 90-95%) never had a
woodruff key on the shaft. I am talking about something that George
likes to talk about. OE VW factory (with the high priestly anointing
just for good measure) alternator that never had a woodruff key. In
fact the 5% I am remembering may be from swapping alternators on Rabbits
or Jettas. As long as you take the pulley and fan off the old one and
swap it over to the new one in with the parts in the same order you will
be fine. Also when you get a rebuilt alternator you want a Bosch AL27X
not a AL33X. They will both work on the Vanagon and both are 90 amp
units, but the AL27X is a direct replacement which the 33X you have to
fiddle with to make work. Hope this helps.
Ken Wilford
John 3:16
www.vanagain.com
George Goff wrote:
>In a message dated 8/22/05 5:26:35 PM, conradk@MAC.COM writes:
>
><< I'm concerned that without a woodruff key, that there would be some
>movement that would cause wear, etc. >>
>
>As you well should be.
>
>In a message dated 8/22/05 11:54:28 AM, dhaynes@OPTONLINE.NET writes:
>
><< they stopped using the woodruff key. I guess they figure that the pulley
>being driven will further tighten the pulley nut if it should slip. >>
>
>Of course, unless it slips in the opposite (righty tighty, lefty loosey)
>direction whenever you snatch a downshift.
>
>Dispencing with the key does not make sense to me. A nut alone fixing a hub
>relative to a straight shaft cannot be depended on to maintain the
>relationship of the two components. The shaft and the bore of the hub have a sliding
>fit. If only the clamping force of the nut is locating the pulley relative to
>the shaft, then it is really the coefficient of friction of the sides of the
>pulley hub which is generating the force opposing independent rotation.
>
>A key may not be needed for a shrink fit or an interference fit, but it is
>necessary for this application. Even some taper fits use keys. Unkeyed the
>to-and-fro inertial tug-of-war between the alternator and the crankshaft would
>act to loosen the nut as well as to tighten it.
>
>If the hub of the pulley is broached with a keyway and the shaft has a
>Woodruff keyseat cut into it, then I think the Woodruff key itself simply fell out
>of the shipping box somewhere along the way.
>
>George
>
>
>
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