Al,
Great information! Thanks!
A couple of clarification questions:
1.    I understand the fine glacier dust problem, but not sure what you mean
by "inland graded route".
2.    I don't understand what dust has to do with oil changes.
Thanks again,
Bill
90 Westy Syncro
Lake Tahoe
-----Original Message-----
From: Al Knoll <AL_KNOLL@HP-ROSEVILLE-OM2.OM.HP.COM>
To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Date: Tuesday, January 19, 1999 11:14 AM
Subject: Air Filters etc.

>     For really dusty conditions the larger syncro air filter works very
>     well.
>
>     The effectiveness of any air filter element is a product of two
>     characteristics.  First the effective surface of the filter element
>     and second the filtering properties of the element material.
>
>     There was a study done by a heavy equipment mfg regarding oil capture
>     mesh filters versus paper elements.  They found the paper element
>     worked better than the K&N device for filtering properties.
>
>     If you have a syncro you should also clean out the dust trap.  This is
>     a little rectangular box upstream of the filter plenum.  It traps the
>     larger dirt particles using a labyrinth swirl technique to cause the
>     heavier particles to accumulate.
>
>     The deadliest of all dust is glacier dust.  It's so fine that ordinary
>     filters don't do too well at eliminating it and on the Alaska Highway
>     and other inland graded routes 1000Mi oil changes and air filter
>     changes are essential to forestall engine wear.
>
>     al (US Army Arctic Test Center, Ft. Greely AK 1962-63)
>