Bob, thanks for your additional information. Your argumentation about the base
oil's viscosity being 15 instead of 20 sounds logical to me.
The straight-weights do adhere better to the surfaces, that's another reason I
use them in my engine. I drive straight-weight 35 in summer and
straight-weight 25 in colder seasons.
Eric
Heinsberg/Germany
123ignition dealership
Bob Spidell wrote:
Eric,
I'd ad that the base oil for multigrades is actually less then the "W"
oil; e.g. for 20W-50 the base
oil is about 15, since the VIs (viscosity improvers) have an effect when
the oil is cold.
The main problem with straight-weight oils is that they're so thick when
cold--you run the risk
of starving the top end of oil for a few seconds after start-up. OTOH,
the straight-weights MAY
adhere to the surfaces better, offering some protection till the stuff
gets flowing.
There's a LOT of debate about this in the aviation community. The
consensus is that if want the
best of both worlds, or live in a climate of extremes, run the
straight-weight in the summer and the
multi-grade--or at least a lighter straight-weight--in the winter.
bs
[demime 1.01d removed an attachment of type application/x-pkcs7-signature which
had a name of smime.p7s]
|