> But that doesn't explain why 10-30W is not good for it. Although the hp
> output of the mower may exceed that of my van....... :-)

HP isn't the criterion, its the internal design of the bearing, engine lube
pressure,
materials, clearances and nominal oil and peak component temperatures (no
doubt amongst others)

10-30W could be far too low viscosity under cold conditions.
And the XX-YYW classification system doesn't inply that the viscosity is
higher at hot temps,
just that it lubrication properties 'simulate' that of a a YY straight oil
at the upper temps and XX when cold.
Think of the origins of the classification system - a large body of
knowledge about straight oils and little if
any about multi-weight oils.

Engineering can be a very grey matter (!), whereas arithmetic is (usually)
quite black and white - but not always.

Would we be able to compare a British Hi Fi at 25 Watts/channel with a US
spec of something like 100 Watts,
just take most things with a pinch of salt, and always try and compare like
with like (they're about the same!).
Another tip is to trust that design engineers know a little bit more about
what they've designed than they are usually
given credit for, especially when it comes to Vanagons!

Clive
'88 Syncro

----- Original Message -----
From: "John Brush" <jbrush@AROS.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, August 21, 2002 6:15 AM
Subject: Re: Oil Weight Reccomendation

> >>I am ignorant of why straight weight even exists anymore. (and on a lot
> >>of
> >>other topics as well)
>
> >30 weight is what the manufacturers of my lawn mowers recommend.
>
> But that doesn't explain why 10-30W is not good for it. Although the hp
> output of the mower may exceed that of my van....... :-)
>
>
> John
>