John Keeney wrote:

"Mike Marron" wrote in message
.. .


(Peter Stickney) wrote:


Allison also Diesel engines for use in tractor-trailers & other such
applications. You can easily pick 'em out by ear, they've got a
distinctive high-frequency scream in their engine note.


I'm not aware of any Allison diesel engines used in semis. The Big
Three truck engine manufacturers are Caterpillar, Cummins and Detroit
Diesel. Going down the road, you can't differentiate between the three
by the sound alone and I suspect the high-freqency scream you're
referring to is simply the turbo.



They are in a lot of school buses, some semi-tractors & heavy equipment
but they're not as popular in semis as some of the others.
I've even seen turboed Allison V-8 diesels on pulling tractors; like
a bomb going off when they snapped the throttle open and shut.




I think those are actually Detroits, Allison doesn't make a diesel.
Most 92 series Detroits have a turbo and roots type blower in normal
operation. Big, ugly and dirty. Good for powering auxiliary wire
stringing equipment and motor torpedo boats. At least that's what an
old buddy told me was powering his Viet Nam river boats, a pair of
Detroits. The 71 series had the familiar blower you see on drag racers
and such. As far as school buses and medium duty trucks ( tow trucks
and such ) International is making a killing selling those, DT406's and
DT466's.

General Motors made diesels under the Detroit name and transmissions
under the Allison name for heavy applications. Confusion might come
from valve cover stickers that include both names when GM consolidated
operations.

http://www.allisontransmission.com/c...tory/index.jsp

Wow, looks like GM sold Detroit Diesel to Daimler/Chrysler. ( Or I
should say Daimler/Chrysler bought out Detroit Diesel. )
http://www.detroitdiesel.com/Corporate/corp_history.asp