Well,
if temperature plays any significant role in the viscous coupling locking
up, it seems that we should see VCs in hot climates having a greater rate of
failure. Does anyone have any evidence to support this?
Bill
90 Westy Syncro
-----Original Message-----
From: Darrell Boehler <midwesty@MIDWEST.NET>
To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Date: Friday, April 23, 1999 5:32 AM
Subject: Re : How VC's work

>-----------------
>Hi Volks,
>    I have no syncro and do all my off roading with an 8n ford tractor. But
>couldn't ignore the syncro thread any longer. I have no practical knowledge
>of syncro except it seems to me they are a pita to work on compared to a
>2wd. I have helped pull an engine and a front differential.   I have some
vw
>service training books from fellow list member David Drew, thanks David.
>This is what they have to say about vc and this is  a quote.
>
>    When the speed difference between the two shafts becomes greater than 6
>percent , which could happen if the rear wheels lost traction on a road
>surface, the outer splined plates connected to the flanged shaft begin to
>cut or shear the silicon fluid.  The shearing action of the fluid causes
>internal heat and the result is a sharp increase of the fluid's viscosity.
>It becomes more difficult for the fluid to become sheared and the coupling
>locks up.
>    Because of the rapid rise in temperature and pressure, lock-up occurs
>very quickly. In about 1/10 second or 1/4 turn of the tire.
>    Power is transmitted between the plates with fluid as a medium.
>
>Unquote. The book has a graph that shows the fluid can go from goes from a
>minus 30 degrees C to 100 degrees C nearly instantly.  Note.  The flanged
>shaft mentioned above is connected to the front differential.
>Darrell
>