[Attachment(s) from William Barber included below]
Here are several photos of Q SD7s and SD9s with spark arrestors and one photo of an SD with an extended stack modification. Just as a matter of information, EMD's basic manifold for Roots blown engines was considered a spark arrestor as they had baffles in them that caused the exhaust flow to circulate with the intent to reduce spark emissions. However, in later years, I don't believe that the basic manifold qualified as a spark arrestor as state and local laws became more restrictive. A concern that EMD had as after market spark arrestors were developed and applied, was that some could and did increase back pressures within the engine. Such back pressure could lead to problems including poor combustion (EMD 2 cycle engines depend of clean savaging of exhaust gases when the intake ports are open.), premature exhaust valve failures and cylinder head failures due to overheating.
These are not my photos. While I would like to credit the individual photographers, they are unknown to me. I have received these photos in e-mails over the years..
Bill Barber Gravois Mills, MO
SD9 451
SD9 350 Denver 1968
SD9 347 Bloomfield, CO 1966
SD9 334 McCook, NE 1970
SD9 450 and 454
SD7 407 Lincoln, NE no date with extended straight stacks.
Tue Sep 29, 2015 7:48 pm (PDT) . Posted by:As I recall, spark arresters were required in Nebraska by state law. They were common on Lines West, but not so much on Lines East. Somebody with a better memory might wish to weigh in on this.
Nelson Moyer
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Attachment(s) from William Barber | View attachments on the web
6 of 6 Photo(s)
Posted by: William Barber <clipperw@gmail.com>
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