Lawrie,
See below:
Lawrie Alexander wrote:
>
> Charley........
>
> "diversity of temperatures"? I can't think of two places in the country
> (where MGBs would be in regular use, anyway) where the temperatures vary as
> much as the temperature variation inside an engine. Some of the passageways
> and ports inside an overdrive unit are so small that it seems a straight 30
> weight oil can circulate more easily, while providing adequate strength and
> lubricating qualities for the gearbox.
By "diversity...." I meant the climatic temp spreads as the seasons
change. That's the way the lube charts in the manuals are organized.
For instance, for temps around 10 F, the chart 0n page 21 of the
Driver's Handbook ('62 - '70) in my Bentley manual specifies 10W or
10W-30. As far as small passages goes, I'm running 20W-50 in my
motorhome's Dodge 360, which has hydraulic lifters. What oil passages
can be smaller than the passages in those lifters?
>
> That, at any rate, is my logic for using straight 30wt rather than 20-50,
> although it is tempered by the fact that I believe shop manuals that stated
> "engine oil" were first written before the common usage of multi-weight
> oils.
As you'll see above, the shop manuals I'm referring to - Bentley,
Haynes, Chilton - SPECIFY multi-vis oils for both the engine and
gearbox. Obviously, multi-viscosity oils were around when they were
published.
In any event, what I wrote about had nothing to do with viscosities.
I wrote about the recommendation by various "experts" that non-detergent
oil be used in the MG overdrives. So far, no one has provided a
reasonable explanation.
CR
> Lawrie
> British Sportscar Center
>
> -----Original Message-----
> From: Charley & Peggy Robinson <ccrobins@ktc.com>
> To: frank krajewski <frankk@intap.net>
> Cc: MG List <mgs@autox.team.net>
> Date: Tuesday, August 15, 2000 2:44 AM
> Subject: Re: OD
>
> (SNIP)
> > There was a spirited thread lately about oil viscocities to use in the
> >gearbox. I think straight 30 weight won out but for the life of me I
> >couldn't see why, given the diversities of temp extremes around the
> >country as the seasons change.
> >
> > Hope this helps,
> >
> > Charley Robinson
> > '69 B
> >
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