Gleaned from the pages of British Car #69, October-November 1997, pg. 45
"Viscosity is a measure of the thickness of the oil at a given
temperature. The traditional way in which viscosity is measured is to
place a set volume of the oil into a device with a calibrated orifice at
the bottom, and to time the oil as it flows through the orifice. The
viscosity number is the time (in seconds) that it takes for the oil to
flow out of the orifice. From this, you can see that the higher the
viscosity number is, the thicker the oil. [...] The "w" stands for
winter, and it means that the oil meeting that viscosity was tested at
zero degrees. Viscosities listed without the "w" were tested at 200
degrees."
Hope this helps. Now I've got to put this stack of British Car magazines
back in order. One day I will make a index of all these issues and make
finding stuff like this easy!
Edwin
'77 MGB
"I'm tryin' to think but nuthin' happens."
-- Curly Howard (the stooge)
Check out The MG Filling Station at:
http://members.fortunecity.com/mowogmg
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