J Burns presented the following explanation :
On 8/7/15 2:07 PM, FromTheRafters wrote:
Muggles was thinking very hard :

What's SB, & SA mean?

SB Obsolete
CAUTION: Not suitable for use in most gasoline-powered automotive
engines built after 1951. Use in more modern engines may cause
unsatisfactory performance or equipment harm.

SA Obsolete
CAUTION: Contains no additives. Not suitable for use in most
gasoline-powered automotive engines built after 1930 Use in modern
engines may cause unsatisfactory performance or equipment harm.

http://www.api.org/~/media/files/cer...glish_2013.pdf


I'd like to find out the specs for each service grade, and when it became
available.

Non-detergent oil is recommended for compressors, but I've read of a 1964
Sears compressor, still in service in 2011, whose manual recommended
detergent oil.

I see two possibilities: it was a misprint, or engineers knew that the
detergent oil on the market (maybe it was SD) did not absorb water.

Maybe this helps, but I suspect not much:

http://www.penriteoil.com.au/tech_pd...ifications.pdf

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