On Sat, 25 Aug 2007 00:02:09 -0700, "Calif Bill"
wrote:


wrote in message
.. .
On Fri, 24 Aug 2007 09:43:13 -0700, "Calif Bill"
wrote:


wrote in message
...
On Thu, 23 Aug 2007 21:15:47 -0700, "Calif Bill"
wrote:


"Del Cecchi" wrote in message
...

wrote in message
news snip

Now, as temperature of the gasses within the combustion chamber and
thus the pressure, is higher then ambient temperature and pressure at
the bottom of the power stroke the flow should be from the high
pressure area to a lower pressure area. In which case the engine
would
not receive any air for the next stroke.

So, where does the two stroke diesel engine get the air necessary to
support combustion of the next injection of diesel fuel if not
through
the use of a mechanical air pump, usually referred to as a "Blower"
in
D.D. parlance

Presumably it would get them by using the crankcase as a compressor
like
a
gas 2stroke does.

Whether it is possible to get the necessary compression for ignition,
especially while at cranking speed, while dealing with transfer ports
etc
is left as an exercise for the student.

del

2 stroke diesels will run without a blower. I have a model airplane
engine
diesel that jsut uses the crankcase like a gas rig. And there were a
lot
of
those 1 lunger diesels in Montereys, etc, that did not have a blower.


Sure you do and it worked just like a glow plug engine. You mixed oil
for lubrication and some nitro-benzine, or something like that, and it
ran. Exactly as do sea scooters, 2-stroke motor cycles and chain saws.

And the reason is that you use the bottom of the piston coming down on
the power stroke to compress the fuel/oil mixture in the crank case to
force it into the combustion chamber.

But we were talking specifically about a Detroit Diesel 2-stroke and
the fact that it does need the mechanical driven "blower" to run.




Bruce in Bangkok
(brucepaigeATgmailDOTcom)

No, the statement was all diesels require a blower. There were lots of
old
fishing boats with 1 and 2 piston diesels, that did not require a blower
to
run. But they were designed like gas 2 stroke to use the crankcase as the
compressor.

I had assumed that as the original post was concerning s 3-53 Detroit
Diesel engine we were still talking about D.D. engines, however the
subject seemed to have slipped a bit, Mia Culpa.

But I am interested in these 1 and 2 piston diesels, used in fishing
boats that did not use a blower? can you tell me the approximate
period they were in use and what the manufacturer was?



Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Early 1950's late 40's. Lot of Monterey's used them. Just use to hear them
as they ran. About one explosion every 5-6 seconds. Montereys were built
and designed in Monterey, Calif and used in the sardine fisherey.


That is interesting. If anyone has any additional information on these
engines I would really like to find out what they were using.

On the New England coast engines of this type were long gone although
some of the older fishermen used to talk about one cylinder gasoline
inboards , possibly Fairbanks, that could be reversed by moving the
manual spark lever to the point that ignition was so far before TDC
that the engine kicked back and ran in reverse.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)