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From: gvcormack@watmum.UUCP (Gordon V. Cormack)
Newsgroups: net.auto.tech
Subject: Re: What motor oil should I use?
Message-ID: <334@watmum.UUCP>
Date: Sat, 16-Nov-85 09:04:44 EST
Article-I.D.: watmum.334
Posted: Sat Nov 16 09:04:44 1985
Date-Received: Sat, 16-Nov-85 20:58:38 EST
References: <561@ihwpt.UUCP> <2435@cal-dbb.fluke.UUCP> <822@whuxl.UUCP>
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Organization: U of Waterloo, Ontario
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> HISTORY OF MOTOR OIL 
> Quoted from RIDERANNUAL - 1984
> "Back in the 1930's, Society of Automotive Engineers (SAE) developed service
> classifications for engine oils. The first were SA and SB. 

This history may be essentially true, but the names SA, SB, ... SE
only came into use in the early 70s.  Before then, the service 
categories used to label motor oil were ML, MM, and MS.  MS was
the best, and was required by all manufacturers.  When the S categories
came along, SD was said to be equivalent to MS.  I don't know for
sure the mapping between {ML, MM} and {SA, SB, SE}.

The S stands for "spark" ignition (gasoline) engines.  CC etc. is a
similar set of scales for "compression" ignition (diesel) engines.