mgs-owner@triumph.cs.utah.edu wrote:
> >Heh. You're confusing motor oil with gear oil. The viscosity indices for
> >each are different. A 90W gear oil and a 30W motor oil are about the same.
>
> You know Jason, I've looked at 90W gear oil and thought that it just didn't
> look as viscous as I thought it should. Now I know why. I had no idea the
> viscosity scales were different.
Properly, it would appear that the viscosity indexes are the same,
but the measuring temperature is different. So gear oil is "rated" as
though it is thicker because it is tested at a lower temperature so
the oil is naturally thicker.
From the VTR web pages, it mentions "Gear oil viscosity is measured
at 150 F vs. 210 F for motor oil. Therefore, 40 W motor oil is
the same as 95 W gear oil".
If you can handle visiting a Tri**ph web site, that info was
gleaned from: http://www.vtr.org/maintain/lubricants-redline.html
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Trevor Boicey 1992 Celica GT (95% of the driving I do)
Computer Engineer 1975 MG Midget (95% of the repairs I do)
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