Calif Bill wrote:
"Tim" wrote in message
ps.com...
On Aug 20, 10:41 am, Bob wrote:

Yep, they used to be pretty common main engines in small workboats and
utility craft, now mostly used for deck engines and gen sets. The
marine engine configuration produces just over 100 hp naturally
aspirated.

Bob-
Bob, by searching around the typical listings on a naturally aspirated
3-53 is about 75 hp. Which I feel is more realistic. I could be
wrong, though.

http://www.usedboats.com/index.php?s...istoryback =1


http://www.adieselengine.com/new_page_1.htm
shows 101 hp for the 3-53 and 175 for the 3-53T And since it shows a T I
would assume turbocharged. As the 6-71 with a blower was a 6V-71. the same
blower that was used for years on dragsters and driven via a Gilmer belt.


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

"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

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

A "blower" generally refers to a direct driven super charger, not an
exhaust driven turbo charger.

On Wed, 22 Aug 2007 12:27:55 GMT, "Pete C."
wrote:

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

A "blower" generally refers to a direct driven super charger, not an
exhaust driven turbo charger.

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)

wrote in message
...
On Wed, 22 Aug 2007 12:27:55 GMT, "Pete C."
wrote:

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

A "blower" generally refers to a direct driven super charger, not an
exhaust driven turbo charger.

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)


Gotcha. I was confusing "blower" with turbocharger as Pete C. pointed out.

Eisboch

On Wed, 22 Aug 2007 21:05:57 +0700, wrote:

On Wed, 22 Aug 2007 12:27:55 GMT, "Pete C."
wrote:

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

A "blower" generally refers to a direct driven super charger, not an
exhaust driven turbo charger.

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.

Is anyone at rec.crafts.metalworking reading this thread??
If not, I suggest we (at rec.boats) stop further crossposting there.

On Wed, 22 Aug 07, jtay wrote:
Neither being a two-stroke nor using diesel oil (nor indeed the
combination) requires a blower/turbo for such an engine to operate.

Running a Detroit 4-53 without a blower (and maybe all Detroit 2
strokes -shrug- I dunno) would indeed take a complete and major league
re-design. Not just a few bolt on changes for sure.

Rick

On Wed, 22 Aug 2007 11:29:44 -0500, lid wrote:

On Wed, 22 Aug 07, jtay wrote:
Neither being a two-stroke nor using diesel oil (nor indeed the
combination) requires a blower/turbo for such an engine to operate.

Running a Detroit 4-53 without a blower (and maybe all Detroit 2
strokes -shrug- I dunno) would indeed take a complete and major league
re-design. Not just a few bolt on changes for sure.

Absolutely right. The Detroit 2 stroke design requires a blower to
move new air into the piston and purge the ehaust gases. It will not
run without it, and little or no increase in volumetric efficiency is
achieved. A turbo charger on the other hand is designed to increase
the air charge to the piston above atmospheric pressure, and therefore
horsepower is increased as the effective cylinder volume is increased.

The confusion arises from the fact that a Detroit blower can also be
used on a gasoline engine as a supercharger. Same basic device but a
different purpose and result.

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

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)