At 02:54 PM 8/6/98 +0000, James wrote:
>Yep your gear box will need an oil chainge every 3000 miles if less.
>Engin oil is not designed for use in a gearbox. The 90W oil is ideal
>for the Spitfire. It needs the high sulpher content to stop the metal
>wearing. The gearbox oil is not stressed by the High Pressures in the
>gearbox where as the engin oil will be cut up.
>
Before Ed Hamilton (and others) jump in here, I'll tell you the findings:
modern 90W gearbox oil is TOO SLIPPERY for the Spit overdrive box. If you
put it in you will feel it slipping in Direct Drive when starting from a
standstill.
The List wisdom is to use a good straight 40 or 50 weight engine oil. This
will provide the viscosity the pump needs to work. What is the longest
any Listers have used this in a gearbox?
Generically speaking, James is right, "hypoid" gear oils are made to
protect the sliding surfaces of gears, and should be used when specified.
But the O/D trans in the Spit seems to be an exception.
I wouldn't advise using a multi-viscosity like 20W50, though. Use the
straight weight stuff. You may have to go to a speed- or race-shop to get
it.
To learn more than you ever wanted to know about lubricants, spend some
time reading the articles by Red Line Oils on the Triumph maintenance pages,
http://www.vtr.org/maintain/maintain.html
Sincerely,
Atwell Haines
'79 Spitfire FM96062 UO
Succasunna, NJ USA
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