Detroit 353 diesel -- aluminum block? How to tell?
 

PhantMan wrote:
The "blower" just provides the normal air pressure required to run the
engine (other 2 stroke designs do the same thing with crankcase
vacuum/pressure). But a "supercharger" would provide more than that.
An extra (super) boost so to speak. Thus the use of separate
terminology. Izat about right?

Wayne.B:
Almost. Superchargers and turbochargers both generate boost pressure,
the difference is in how they are driven. Superchargers are direct
drive (belts, gears, etc), turbos are driven by exhaust pressure.

Right. Which is why I was confusing the "blower" term with a
"supercharger" rather than "turbocharger", since the blower is not
exhaust driven.
My ambiguous message up there was referring to the reason the DD
blower can be considered part of a "natually aspirated" system rather
than supercharged.
I somehow don't think I'm making sense today.

Rick

Detroit 353 diesel -- aluminum block? How to tell?
 

Eisboch wrote:
"JohnM" wrote in message
m...

All two-stroke Detroits have a blower. It's necessary to the operation of
the engine, does the job that crankcase pressure does in a little
two-stroke. On the inline motors it mounts on the side of the block.

John

If a "blower" is defined by you as a turbo (i.e. .., device to increase air
flow into the cylinders), then you are in error. I know several people with
2 stroke DD 6-71's. Some are naturally aspirated, some have turbos
(blowers).

Eisboch



Find a cutaway picture of a Detroit Diesel, you'll see what the blower
does and you can figure out how. Don't pay no 'tention to turbos, a
turbo isn't a blower. A naturally aspirated Detroit two-stroke has a
blower.

John

Detroit 353 diesel -- aluminum block? How to tell?
 

In article ,
_ wrote:

[...]


The Detroit Diesel is a two stroke, diesel. The piston goes down on
the power stroke and comes up on the compression stroke. Without the
mechanical driven "blower" which simply blows air in through the
cylinder ports and through the exhaust ports at the beginning of the
compression stroke there would be no way to get a charge of air into
the engine.

If you wanted to increase the pressure and volume of this air flow you
could add a exhaust driven compressor before the "blower", But you
must have the "blower" for the engine to run.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Neither being a two-stroke nor using diesel oil (nor indeed the
combination) requires a blower/turbo for such an engine to operate. It is
true that engines can be designed so that, were the blower/turbo with which
they are normally equipped to be removed they would not run, that would be
due to other design decisions, not to the choice of fuel, method of
ignition, and/or two/four-stroke operation.

Being a two-stroke, and a Detroit, it requires a blower to operate.
Come to think of it, I've never heard of any engines that are two
stroke and do not use forced induction of one form or another. Even
little chain saws use the crankcase volume as a blower.
Seems as if those two eliminated strokes--intake and exhaust--are
taken up by the blower.
How would you build an 2-stroke engine without forced induction?

--
B.B. --I am not a goat! thegoat4 at airmail dot net

Detroit 353 diesel -- aluminum block? How to tell?
 

On Thu, 23 Aug 2007 11:08:52 -0500, "B.B."
u wrote:

In article ,
_ wrote:

[...]


The Detroit Diesel is a two stroke, diesel. The piston goes down on
the power stroke and comes up on the compression stroke. Without the
mechanical driven "blower" which simply blows air in through the
cylinder ports and through the exhaust ports at the beginning of the
compression stroke there would be no way to get a charge of air into
the engine.

If you wanted to increase the pressure and volume of this air flow you
could add a exhaust driven compressor before the "blower", But you
must have the "blower" for the engine to run.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Neither being a two-stroke nor using diesel oil (nor indeed the
combination) requires a blower/turbo for such an engine to operate. It is
true that engines can be designed so that, were the blower/turbo with which
they are normally equipped to be removed they would not run, that would be
due to other design decisions, not to the choice of fuel, method of
ignition, and/or two/four-stroke operation.

O.K. Assuming that your statement is correct And starting from the
power stroke of a two stroke diesel engine.

(1) Diesel fuel is injected into the combustion chamber where air has
been compressed until it exceeds the ignition temperature of the duel.

(2) The rapidly expanding gases created by the burning fuel act to
push the only movable part of the combustion chamber, the piston
downward. At the bottom of the power stroke the gasses inside the
combustion chamber still are far hotter then ambient temperature and
thus exceed ambient pressure.

(3) the piston having reached the bottom of its power stroke begins to
be driven upward by the crankshaft and connecting rod. When it piston
reaches roughly the top of its compression stroke another injection
event occurs.

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


Being a two-stroke, and a Detroit, it requires a blower to operate.
Come to think of it, I've never heard of any engines that are two
stroke and do not use forced induction of one form or another. Even
little chain saws use the crankcase volume as a blower.
Seems as if those two eliminated strokes--intake and exhaust--are
taken up by the blower.
How would you build an 2-stroke engine without forced induction?



Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Detroit 353 diesel -- aluminum block? How to tell?
 

wrote in message
...
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

Detroit 353 diesel -- aluminum block? How to tell?
 

"Del Cecchi" wrote in message
...

wrote in message
...
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.

Detroit 353 diesel -- aluminum block? How to tell?
 

Bruce:
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"

"Del Cecchi" wrote:
Presumably it would get them by using the crankcase as a compressor like
a gas 2stroke does.

Problem with that assumption is, a DD crankcase is designed like a 4
stroke, with an oil bath and filter. A DD crankcase is not connected
in any way to the intake port (not to mention, a DD cylinder has no
exhaust port. it has an exhaust valve, and rocker arms, and pushrods,
and cam, like a 4 stroke). A DD 2 storke design is nothing like the 2
stroke design we're all familiar with for outboards etc.
Its air intake comes directly from outside, not through the crankcase.
And without a blower to push the air in, it won't run.

Rick

Detroit 353 diesel -- aluminum block? How to tell?
 

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


"Del Cecchi" wrote in message
...

wrote in message
...
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)

Detroit 353 diesel -- aluminum block? How to tell?
 

"Calif Bill" wrote:
2 stroke diesels will run without a blower. I have a model airplane engine
diesel that jsut uses the crankcase like a gas rig

All 2 strokes are not designed alike. The term "2stroke" refers to how
often the piston goes up/down per power stroke. Not how air or fuel is
fed to the cylinder. The crankcase of you little diesel 2 stroke is
designed like an outboard. A DD crankcase is designed like your
automobile engine's (assuming it's a 4 stroke).
A DD 2 stroke can't run without a blower.

Rick

Detroit 353 diesel -- aluminum block? How to tell?
 

On Thu, 23 Aug 2007 22:36:31 -0500, "Del Cecchi"
wrote:


wrote in message
.. .
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

Nope you are really talking about two different devices. The gas/oil
mix fueled 2-stroke provides lubrication and fuel for the engine.
Whether the oil is injected into the air/fuel stream or pre-mixed
makes no difference. Since chain saws, yamahas and model aircraft
engines, including model diesel engines run this way proves that it
will work.

But, we were discussing specifically Detroit Diesel 2-styroke diesel
engines that do not premix the oil and fuel. Quite the opposite, they
are vary carefully separated. Thus, a blower scavenged 2-stroke
diesel will not run without it's blower.





Bruce in Bangkok
(brucepaigeATgmailDOTcom)