John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.

Bill

From Engineman

On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are commression ignition (just like other diesels)
and hence do not rely on ignition timing. (I believe)

--
John G.

John G brought next idea :
Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are coMpression ignition (just like other diesels) and

hence do not rely on ignition timing. (I believe)

I will have to get spellchecker working??

--
John G.

"John G" wrote in message
. au...

Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are commression ignition (just like other diesels) and
hence do not rely on ignition timing. (I believe)

--
John G.

The motorcycle hypothetical caused me not to reply initially, because there
are two issues the the ignition, as previously mentioned, and the type of
intake valve used.

Battery and spark-coil ignition, as the previous poster said, will be off on
timing but may allow it to run. Electronic ignition may be closer. Magneto
ignition probably won't allow it to run backwards at all because the pulse
to create the spark won't occur until well after TDC.

On the valves, reed-type or piston-port, yes. Rotary-valve, probably not.

I started a lot of model airplane engines backwards when I was a kid,
unintentionally. They had reed valves (my little Cox engines) or rotary type
(McCoy Red Head). My recollection of the McCoy, though, is that it would
start backwards, so it may have been fairly symmetrical. The Coxes did it
all the time, if you weren't careful.

Those engines were glow-plug ignition and, like compression ignition
engines, didn't care which way they were running from an ignition
standpoint.

--
Ed Huntress

engineman wrote:
The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.
Actually, they probably need to do some stuff to make it run
backwards properly, but it might not be a huge deal on a large
engine like that. It likely has a blower of some sort that needs
to run the right direction all the time. If it uses valves, then
the cam timing needs to be switched. And, likely at least part
of the injection pump needs to run the right direction. Some of
that stuff may be purely electrical, so no need for reversing gears
on the pumps.

Simple 2-strokes of the motorcycle, chain saw, model aircraft
sort will run quite well backwards. It used to be great fun to
run the early Saabs backwards and then switch off to an unsuspecting
driver. Great hilarity!

My old Chevy Vega would Diesel backwards and blow all the hoses
off the intake manifold after shutting it off hot. So, I learned
to shut it off, wait for it to hit zero speed and then pop the clutch
to prevent it from starting up backwards. It would run for an amazing
time on fumes in the exhaust.

Jon

"engineman" wrote in message
...
John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.

I imagine it will depend on the specific engine, but I seem to recall an old
outboard that had no reverse. You just started it in reverse or something
like that.

On 10/30/2011 12:15 AM, John G wrote:
\\
I will have to get spellchecker working??


Push it backwards!

"John G" wrote in message
. au...
Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are commression ignition (just like other diesels) and
hence do not rely on ignition timing. (I believe)

--
John G.



In my limited knowledge the timing is "done" by when the fuel is injected by
the fuel pump. I dont know if ship sized engines are the same as truck / car
diesel engines.

"Bob La Londe" wrote in message
...
"engineman" wrote in message
...
John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.

I imagine it will depend on the specific engine, but I seem to recall an
old outboard that had no reverse. You just started it in reverse or
something like that.


I'm not familiar with the more modern large diesel, but older ships engines
had individual injection pumps which ran off a cam shaft seperate from valve
cam shaft. They were started by using compressed air on an additional valve
on one of the cylinders. The injection cam shaft would be in either the
forward or reverse position. Incidently,each injector pump drive could be
lifted off the cam by using a special spanner. If you weren't getting full
power out of it, you could isolate which cylinder was the culprit by lifting
each injector individually. When you lifted one and found that it didn't
cause the injector racks to open up more, you had found the faulty cylinder.
Oil drilling rig diesels had butterfly valves on the air intakes as natual
gas getting into the deisels could cause them to " run away", and they
couldn't be stopped by just shutting down the throttle. Closing the valves
on the air intakes stopped them dead

On Sun, 30 Oct 2011 00:23:49 -0400, "Ed Huntress"
wrote:

I started a lot of model airplane engines backwards when I was a kid,
unintentionally.

Backwards starting is even more likely on 4-stroke model glow engines.
Amazingly, even the throttle works. I asked my fellow modelers how
that is even possible, but nobody knew and nobody cared. The
explanation is quite simple: Since there is no fuel pump, model
engines feed pressure from the exhaust into the tank to help fuel
feed. When the engine starts backwards, fuel is slurped from the tank
through the pressure hose into the exhaust. The carburetor valve now
acts as an exhaust restriction valve to control engine power.

They had reed valves (my little Cox engines) or rotary type
(McCoy Red Head). My recollection of the McCoy, though, is that it would
start backwards, so it may have been fairly symmetrical.

Some rotary valve engines had the option to rotate the front part of
the crank case 90 degrees to enable backwards running. I think some
Enya engines have this feature. Here you can see how the crank case is
made from two parts screwed together:
http://ruwatches.com/thestore/images/Enya%20engine.jpg

The Coxes did it
all the time, if you weren't careful.

I seem to remember the Coxes had a spring system on the prop shaft
that would automatically stop and restart the engine the right way.
Here's a picture where the system can be seen:
http://lh6.ggpht.com/-NYNdjF-hKbs/SU...9468476785.jpg

The primary use of this spring is to start the engine. The reverse
protection is a nice bonus.

Those engines were glow-plug ignition and, like compression ignition
engines, didn't care which way they were running from an ignition
standpoint.

I am not very familiar with diesels, but on normal car engines, I am
quite sure the ignition timing is controlled by the fuel injectors.
The engine compresses only air, and the fuel is injected into the hot
air at just the right time. Since there is no risk if early ignition
or detonation (only air is compressed), a turbo is an attractive
option for a diesel.
--
RoRo

On Sat, 29 Oct 2011 18:20:28 -0700, engineman wrote:

John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put it
in 1st gear. Then four of your not so bright friends, two on each side,
pushed you and the bike BACKWARDS!! Remember there are two each side so
they should be able to keep you from falling over. After the bike gains
some momentum you pop the clutch. Now, the question is: WILL THE BIKE
START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why not? The reason
that it comes up is that I read about a new class of ULCCs
(UltraLargeCrudeCarriers -- Way big mutha oil tankers) that have 2
cycle diesel engines with NO transmission, clutch or reduction gears of
any sort. The drive shaft comes out the back of the engine and goes out
the back of the hull and the propeller is bolted directly to the end of
it No gears, no clutch, no nothing. The way that they reverse it is by
shutting of the engine and then restarting it BACKWARDS!!?! It is
designed to do this, I'm wondering if all 2 cycle engines will run
backwards or not? Inquiring minds want to know.


Common glow plug aircraft engines will. Easily because their intake,
exhaust, and ignition timing are symetrical about TDC.

Two-stroke spark ignition engines will probably not, the spark is
advanced; extremely unlikely if they are also assymetric breathers.

Larger diesel engines can/will have assymetric intake, exhaust, and
injection timing. To run backwards you just change that timing so
it works the other way.

On Sat, 29 Oct 2011 18:20:28 -0700 (PDT), engineman
wrote:

John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.

Bill

From Engineman

The large marine engines is usually reversed by shutting down and
turning the engine in reverse accompanied with changing the injection
pump(s) timing. Although the engine might well run in reverse without
changing the injection timing it won't produce rated power.


--
John B.

On Sat, 29 Oct 2011 23:54:47 -0400, Gardner
78436578346587364578364578@kjhgfjkerhfjksdhfjkdfh kjhjkgfsdhfjdhfjkhfjkgfh.com
wrote:

On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

The timing is one of those things they thought of when making those
huge marine engines - the stroke is symmetrical so it's timed right (a
camshaft to trigger the fuel shot) running forward or backward.

And the marine engines use a sliding crosshead between the piston
connecting rod and the crosshead connecting rod to the crankshaft, to
keep the offset thrust loads of the crankshaft away from the pistons.

-- Bruce --

"Bob La Londe" wrote in message ...

"engineman" wrote in message
...
John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.

I imagine it will depend on the specific engine, but I seem to recall an
old outboard that had no reverse. You just started it in reverse or
something like that.

Some old *inboards*, too, like the Acadia make-and-break engines used on
fishing boats in the Canadian Maritimes. You reversed them by waiting for
the open flywheel to stop and then kicking it in reverse with your foot.

"Simplify, simplify. We fritter our minds away with detail." g

--
Ed Huntress

"Robert Roland" wrote in message
...

On Sun, 30 Oct 2011 00:23:49 -0400, "Ed Huntress"
wrote:

I started a lot of model airplane engines backwards when I was a kid,
unintentionally.

Backwards starting is even more likely on 4-stroke model glow engines.
Amazingly, even the throttle works. I asked my fellow modelers how
that is even possible, but nobody knew and nobody cared. The
explanation is quite simple: Since there is no fuel pump, model
engines feed pressure from the exhaust into the tank to help fuel
feed. When the engine starts backwards, fuel is slurped from the tank
through the pressure hose into the exhaust. The carburetor valve now
acts as an exhaust restriction valve to control engine power.

Jeez. And I'm listening to this, thinking about all of the engines that were
SUPPOSED to start during my lifetime, but wouldn't, and here's one that
shouldn't, but does. d8-)

They had reed valves (my little Cox engines) or rotary type
(McCoy Red Head). My recollection of the McCoy, though, is that it would
start backwards, so it may have been fairly symmetrical.

Some rotary valve engines had the option to rotate the front part of
the crank case 90 degrees to enable backwards running. I think some
Enya engines have this feature. Here you can see how the crank case is
made from two parts screwed together:
http://ruwatches.com/thestore/images/Enya%20engine.jpg

Interesting.

The Coxes did it
all the time, if you weren't careful.

I seem to remember the Coxes had a spring system on the prop shaft
that would automatically stop and restart the engine the right way.
Here's a picture where the system can be seen:
http://lh6.ggpht.com/-NYNdjF-hKbs/SU...9468476785.jpg

I had one or two of those, but mostly I just had the plain (.049) engines
that you propped with your finger. My finger was bloody or sore half the
time when I was around 10 - 12 years old.

The primary use of this spring is to start the engine. The reverse
protection is a nice bonus.

The spring start was Ok except that the engine would try to fire when you
were winding the spring back. It was rough on the engine but those little
Coxes were hard to destroy. They were a very clever piece of design, and we
cited them as an example of "design for manufacture" back in the '70s at
_American Machinist_. The crankcase was an extrusion.

Those engines were glow-plug ignition and, like compression ignition
engines, didn't care which way they were running from an ignition
standpoint.

I am not very familiar with diesels, but on normal car engines, I am
quite sure the ignition timing is controlled by the fuel injectors.
The engine compresses only air, and the fuel is injected into the hot
air at just the right time. Since there is no risk if early ignition
or detonation (only air is compressed), a turbo is an attractive
option for a diesel.
--
RoRo

Right. And if you really want to confuse yourself, look into the model
airplane "diesels," which aren't really diesels at all, since they don't
have injection. They're Homogeneous-Charge, Compression-Ignition engines --
paradoxically, one of the types being heavily researched right now for
automotive applications.

--
Ed Huntress

"engineman" wrote in message
...
John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.

Bill

From Engineman

Polaris & Ski-Doo (maybe others now) both have "electronic" reverse on
their snowmobiles and possibly ATV's, too.
You can see here that it stops the engine briefly and instantly re-fires
it in reverse: http://www.youtube.com/watch?v=opwQ15uic_g

On Sun, 30 Oct 2011 15:11:54 +1100, John G
wrote:

Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are commression ignition (just like other diesels)
and hence do not rely on ignition timing. (I believe)

Wrong. They still have timing, just no ignition.

They have to time the squirt of fuel into the combustion chamber at
the right moment (5 or 10 degrees before TDC) so the main flame front
goes off right after TDC. If you squirt the fuel in way early and
it's hot enough to light off, the engine tries to run backwards.

Which isn't going to be pretty if it was full speed ahead (lots of
inertia built up) and one cylinder goes way early.

-- Bruce --

On Sun, 30 Oct 2011 13:10:50 -0500
"David Courtney" wrote:

snip
Polaris & Ski-Doo (maybe others now) both have "electronic" reverse on
their snowmobiles and possibly ATV's, too.
You can see here that it stops the engine briefly and instantly re-fires
it in reverse: http://www.youtube.com/watch?v=opwQ15uic_g


I first saw this on an old Mercury snowmobile, around the early 70's:

"In 1969 the Model 220 was unveiled, with the 250 debuting shortly
thereafter. Both were based on the 150 cowl style, with the belly pan
thankfully being a separate unit, allowing easier hood removal.
Comparing these to the 150, they look a lot like the 150 on steroids.
Both models were available with electric start (220E, 250E) and reverse
(220ER, 250ER). The reversing mechanism was simple, the driven clutch
was designed to operate in both directions, and the engines had two
separate starters mounted over the toothed flywheel. To put the units
in reverse, one would shut the engine off, flip a toggle switch and
start the motor in reverse! This design was borrowed from their early
"dock banger" outboards, which had no neutral gear but were started in
forward or reverse from the control console."

From not quite halfway down this page:

http://www.mercurysnowmobiles.com/early%20story.htm

I was pretty impressed at the time. My buddy didn't have a clue how it
worked but I pretty much surmised how while watching him shut it off,
flip a switch and start it up again. I recall that it ran "rough" but
it did indeed go backwards...

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On Sun, 30 Oct 2011 15:11:54 +1100, John G
wrote:

Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are commression ignition (just like other diesels)
and hence do not rely on ignition timing. (I believe)
No, the depend on INJECTION timing, which, from what I remember, is
even MORE critical

On Sun, 30 Oct 2011 11:29:40 +0100, Robert Roland
wrote:

On Sun, 30 Oct 2011 00:23:49 -0400, "Ed Huntress"
wrote:

I started a lot of model airplane engines backwards when I was a kid,
unintentionally.

Backwards starting is even more likely on 4-stroke model glow engines.
Amazingly, even the throttle works. I asked my fellow modelers how
that is even possible, but nobody knew and nobody cared. The
explanation is quite simple: Since there is no fuel pump, model
engines feed pressure from the exhaust into the tank to help fuel
feed. When the engine starts backwards, fuel is slurped from the tank
through the pressure hose into the exhaust. The carburetor valve now
acts as an exhaust restriction valve to control engine power.

They had reed valves (my little Cox engines) or rotary type
(McCoy Red Head). My recollection of the McCoy, though, is that it would
start backwards, so it may have been fairly symmetrical.

Some rotary valve engines had the option to rotate the front part of
the crank case 90 degrees to enable backwards running. I think some
Enya engines have this feature. Here you can see how the crank case is
made from two parts screwed together:
http://ruwatches.com/thestore/images/Enya%20engine.jpg

The Coxes did it
all the time, if you weren't careful.

I seem to remember the Coxes had a spring system on the prop shaft
that would automatically stop and restart the engine the right way.
Here's a picture where the system can be seen:
http://lh6.ggpht.com/-NYNdjF-hKbs/SU...9468476785.jpg

The primary use of this spring is to start the engine. The reverse
protection is a nice bonus.

Those engines were glow-plug ignition and, like compression ignition
engines, didn't care which way they were running from an ignition
standpoint.

I am not very familiar with diesels, but on normal car engines, I am
quite sure the ignition timing is controlled by the fuel injectors.
The engine compresses only air, and the fuel is injected into the hot
air at just the right time. Since there is no risk if early ignition
or detonation (only air is compressed), a turbo is an attractive
option for a diesel.
And on a 2 stroke diesel a blower of some sort is not only an
attractive option, but a necessity.

"engineman" wrote in message
...
John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.

Bill

From Engineman

In addition to the problems already mentioned there is the issue of the
oil pump running backwards and not lubing the engine. I had a few bikes
where the gas & oil went into separate tanks and a mechanical pump fed
the oil to the engine.
Art

On Sun, 30 Oct 2011 15:53:08 -0400, wrote:

And on a 2 stroke diesel a blower of some sort is not only an
attractive option, but a necessity.

I know even less of two stroke diesels than diesels in general. Can
you explain why a blower is necessary? Could you not build the engine
just like a gasoline one, except with a fuel injector in the cylinder
head?

Is it about lubrication? You'd need to inject the lubrication oil into
the intake air, but that can't be too difficult.

I understand that if you want to have the crank case oil filled, and
avoid having lubrication oil in the exhaust, you certainly need a
blower.
--
RoRo

On 10/30/2011 11:51 AM, Bruce L. Bergman (munged human readable) wrote:
On Sun, 30 Oct 2011 15:11:54 +1100, John
wrote:

Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are commression ignition (just like other diesels)
and hence do not rely on ignition timing. (I believe)

Wrong. They still have timing, just no ignition.

They have to time the squirt of fuel into the combustion chamber at
the right moment (5 or 10 degrees before TDC) so the main flame front
goes off right after TDC. If you squirt the fuel in way early and
it's hot enough to light off, the engine tries to run backwards.

Which isn't going to be pretty if it was full speed ahead (lots of
inertia built up) and one cylinder goes way early.

-- Bruce--
I seem to recall the old John Deere 2 cylinder engines that were being
run on Diesel and were hot from being worked hard would sometimes run
backwards when you shut them down.

Paul

Since it is 2 stroke there is only the compression and power stroke.
a blower is necessary to blow the exhaust out of the cylinder and blow
fresh air in when the piston drops below the ports.

Engineman

On Oct 30, 4:19*pm, Robert Roland wrote:
On Sun, 30 Oct 2011 15:53:08 -0400, wrote:
And on a 2 stroke diesel a blower of some sort is not only an
attractive option, but a necessity.

I know even less of two stroke diesels than diesels in general. Can
you explain why a blower is necessary? Could you not build the engine
just like a gasoline one, except with a fuel injector in the cylinder
head?

Is it about lubrication? You'd need to inject the lubrication oil into
the intake air, but that can't be too difficult.

I understand that if you want to have the crank case oil filled, and
avoid having lubrication oil in the exhaust, you certainly need a
blower.
--
RoRo

On Oct 30, 5:19*pm, Robert Roland wrote:
On Sun, 30 Oct 2011 15:53:08 -0400, wrote:
And on a 2 stroke diesel a blower of some sort is not only an
attractive option, but a necessity.

I know even less of two stroke diesels than diesels in general. Can
you explain why a blower is necessary? Could you not build the engine
just like a gasoline one, except with a fuel injector in the cylinder
head?

Is it about lubrication? You'd need to inject the lubrication oil into
the intake air, but that can't be too difficult.

I understand that if you want to have the crank case oil filled, and
avoid having lubrication oil in the exhaust, you certainly need a
blower.
--
RoRo

No valves, just ports, you need a blower to clear the exhaust. No
exhaust stroke after all and crankcase induction is a nogo with
monster engines and multiple cylinders. These are not Lawnboys, they
have a pressure lube system and probably a dry sump. Since they turn
so slowly, they can have longer stroke/bore ratios than automotive
diesels, adds to the efficiency. Probably closer to Diesel's original
engine concept than a lot of the engines they call "diesel" these
days. archive.org has some older books for download on diesels. Not
a lot has changed to the basics.

Stan

On Sat, 29 Oct 2011 22:37:34 -0700, Bob La Londe wrote:

"engineman" wrote in message
news:9e9bce26-f50f-442b-
...
John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2 cycle
engines will run backwards or not? Inquiring minds want to know.

I imagine it will depend on the specific engine, but I seem to recall an
old outboard that had no reverse. You just started it in reverse or
something like that.

I had a neighbor with a story about that. For a while he had a boat with
such a motor. He and a friend were out fishing, and had to navigate
through some logs, or something. So there was a lot of backing- and
forthing. They got out into the open river, and Lee made some comment
about being happy they threaded their way through.

To which his friend replied "yup. And boy, the way the motor kept
stalling had my heart in my throat, too".

--
www.wescottdesign.com

On Sat, 29 Oct 2011 18:20:28 -0700, engineman wrote:

John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put it
in 1st gear. Then four of your not so bright friends, two on each side,
pushed you and the bike BACKWARDS!! Remember there are two each side so
they should be able to keep you from falling over. After the bike gains
some momentum you pop the clutch. Now, the question is: WILL THE BIKE
START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why not? The reason
that it comes up is that I read about a new class of ULCCs
(UltraLargeCrudeCarriers -- Way big mutha oil tankers) that have 2
cycle diesel engines with NO transmission, clutch or reduction gears of
any sort. The drive shaft comes out the back of the engine and goes out
the back of the hull and the propeller is bolted directly to the end of
it No gears, no clutch, no nothing. The way that they reverse it is by
shutting of the engine and then restarting it BACKWARDS!!?! It is
designed to do this, I'm wondering if all 2 cycle engines will run
backwards or not? Inquiring minds want to know.

Bill

From Engineman

It depends on the engine. Most model airplane two strokes (which is what
I'm mostly familiar with) have crank-timed crankcase induction. So while
the exhaust and transfer (from crankcase to cylinder) work the same
forward and back, the intake into the crankcase is "one way" (some hot
motors will run -- poorly -- backwards).

There are some itty-bitty reed valve engines that run quite happily in
either direction -- in fact, a Cox 049 reedie will generally start the
opposite of the direction you flip it, when you're trying to flip it
forward. Flipping it backward, it generally starts in the same direction
as the flip. Go figure.

Note that model airplane engines are mostly glow ignition -- that's a
"sorta diesel" cycle where the ignition timing doesn't care about crank
rotation.

Most chainsaw and weed-whacker engines, on the other hand, have a piston-
timed crankcase induction (the piston uncovers a port between carburetor
and case). These have less ultimate power potential than a crank-timed
engine, but they're simpler to make. As mentioned elsewhere, even though
the induction, transfer, and exhaust timing is the same forward and
reverse, the spark will be off.

Scooter engines are probably mostly like chainsaw engines (if not
entirely so). Large motorcycle two strokes often use reed valve
crankcase induction, on the same principal as the little reedies for
model airplanes, but considerably different mechanics. They would still
run crappily, if at all, in reverse, because of spark timing.

Bigger engines start doing wacky (to me) things like running two pistons
in one cylinder with offset cranks (Junkers Jumo), or running ports in
the cylinder and valves in the head (I think it's usually transfer ports
and exhaust valves), or other creative means of improving gas flow. Most
of these are also going to run considerably less well in the reverse
direction.

But my entire experience with bigger engines than weed whacker engines
runs to reading Wikipedia pages.

So, the bottom line is: maybe it will, maybe it won't, and either way a
motorcycle is a stable system moving forward but not back -- so you'd
just fall off anyway.

--
www.wescottdesign.com

The reason
that it comes up is that I read about a new class of ULCCs
(UltraLargeCrudeCarriers -- Way big mutha oil tankers) that have 2
cycle diesel engines with NO transmission, clutch or reduction gears of
any sort. The drive shaft comes out the back of the engine and goes out
the back of the hull and the propeller is bolted directly to the end of
it No gears, no clutch, no nothing. The way that they reverse it is by
shutting of the engine and then restarting it BACKWARDS!!?! It is
designed to do this, I'm wondering if all 2 cycle engines will run
backwards or not? Inquiring minds want to know.

Bill

I am amazed that the engines are designed to be stopped, then restarted
backwards. This, I believe, would take at least some time on the larger
engines, but perhaps not. I have been on a lot of motor vessels in the open
sea, but none as large as I believe you are talking about. Starting and
stopping the engines would take too much time to do some of the delicate
maneuvering required using multiple props to get the vessel to do the
intended maneuver. I do not doubt that this may be the case on longer ships
that take a very long time to stop or turn or even slow down. I just can't
imagine that would be the safest and best way to maintain control over the
vessel, and to get it to respond in a timely and safe manner when
maneuvering. There is a lot of jockeying the throttles and gearing by the
captain during maneuvering a boat for docking, or negotiating tight spaces.
I'm wondering if the response times are adequate for the intended result.

I've spent probably more than 1,000 days on various boats in the open sea,
in the 150 - 250 foot class.

Steve

On Sun, 30 Oct 2011 12:01:16 -0400, "Ed Huntress"
wrote:



"Bob La Londe" wrote in message ...

"engineman" wrote in message
...
John,

Here is a question for you and your metalhead group.

Q: Say you had a 2 CYCLE motorcycle and you wanted to push start
it. Suppose that you got on it and turned on the ignition but didn't
hit the start button. Instead you depressed the clutch lever and put
it in 1st gear. Then four of your not so bright friends, two on each
side, pushed you and the bike BACKWARDS!! Remember there are two each
side so they should be able to keep you from falling over. After the
bike gains some momentum you pop the clutch. Now, the question is:
WILL THE BIKE START WITH THE ENGINE RUNNINGBACKWARDS??!? If not, why
not? The reason that it comes up is that I read about a new class of
ULCCs (UltraLargeCrudeCarriers -- Way big mutha oil tankers) that
have 2 cycle diesel engines with NO transmission, clutch or reduction
gears of any sort. The drive shaft comes out the back of the engine
and goes out the back of the hull and the propeller is bolted directly
to the end of it No gears, no clutch, no nothing. The way that they
reverse it is by shutting of the engine and then restarting it
BACKWARDS!!?! It is designed to do this, I'm wondering if all 2
cycle engines will run backwards or not? Inquiring minds want to
know.

I imagine it will depend on the specific engine, but I seem to recall an
old outboard that had no reverse. You just started it in reverse or
something like that.

Some old *inboards*, too, like the Acadia make-and-break engines used on
fishing boats in the Canadian Maritimes. You reversed them by waiting for
the open flywheel to stop and then kicking it in reverse with your foot.

"Simplify, simplify. We fritter our minds away with detail." g


If you are really dextrous you can catch them with the "spark lever"
just as they come up on compression that last time and they bounce
right back the other way.

They were also used in Maine where I saw one converted to a stationary
engine and used to power an old fellow's boat building shop.


--
John B.

On Sun, 30 Oct 2011 23:16:58 -0700, "Steve B"
wrote:


The reason
that it comes up is that I read about a new class of ULCCs
(UltraLargeCrudeCarriers -- Way big mutha oil tankers) that have 2
cycle diesel engines with NO transmission, clutch or reduction gears of
any sort. The drive shaft comes out the back of the engine and goes out
the back of the hull and the propeller is bolted directly to the end of
it No gears, no clutch, no nothing. The way that they reverse it is by
shutting of the engine and then restarting it BACKWARDS!!?! It is
designed to do this, I'm wondering if all 2 cycle engines will run
backwards or not? Inquiring minds want to know.

Bill

I am amazed that the engines are designed to be stopped, then restarted
backwards. This, I believe, would take at least some time on the larger
engines, but perhaps not. I have been on a lot of motor vessels in the open
sea, but none as large as I believe you are talking about. Starting and
stopping the engines would take too much time to do some of the delicate
maneuvering required using multiple props to get the vessel to do the
intended maneuver. I do not doubt that this may be the case on longer ships
that take a very long time to stop or turn or even slow down. I just can't
imagine that would be the safest and best way to maintain control over the
vessel, and to get it to respond in a timely and safe manner when
maneuvering. There is a lot of jockeying the throttles and gearing by the
captain during maneuvering a boat for docking, or negotiating tight spaces.
I'm wondering if the response times are adequate for the intended result.

I've spent probably more than 1,000 days on various boats in the open sea,
in the 150 - 250 foot class.

Steve

I think that you'll find that most of the larger ships (VLCC, the big
box boats, etc) are all direct drive reversing engines. I believe that
a combination of the giant size of pistons, rods, etc. means that they
can't be designed to run at very high revs, say 100 RPM perhaps, and
the size of any reversing gear and the power they would have to absorb
make the direct drive setup cheaper and less complicated to build.

Yout 150 - 250 ft. boats were something different and likely far more
maneuverable then the "big boats".

An interesting aside I read, was that using a box carrier like the
Emma Maersk it is cheaper to ship a container from China to a West
Coast port then the cost of freight for the box from the port to its
final distention inside the U.S. Obviously internal freight varies
with the distance delivered it does give a good picture of why these
big boats. (and incidentally, part of the reason for moving your
industry off shore)


--
John B.

On 10/29/2011 9:23 PM, Ed Huntress wrote:


"John G" wrote in message
. au...

Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are commression ignition (just like other diesels)
and hence do not rely on ignition timing. (I believe)

--
John G.

The motorcycle hypothetical caused me not to reply initially, because
there are two issues the the ignition, as previously mentioned, and
the type of intake valve used.

Battery and spark-coil ignition, as the previous poster said, will be
off on timing but may allow it to run. Electronic ignition may be
closer. Magneto ignition probably won't allow it to run backwards at all
because the pulse to create the spark won't occur until well after TDC.

On the valves, reed-type or piston-port, yes. Rotary-valve, probably not.

I started a lot of model airplane engines backwards when I was a kid,
unintentionally. They had reed valves (my little Cox engines) or rotary
type (McCoy Red Head). My recollection of the McCoy, though, is that it
would start backwards, so it may have been fairly symmetrical. The Coxes
did it all the time, if you weren't careful.

Those engines were glow-plug ignition and, like compression ignition
engines, didn't care which way they were running from an ignition
standpoint.

Is anyone familiar with the old drag-saws used to buck up logs. I
remember the engine could be started either way, depending on the way
you spun the flywheel.

Paul

On 10/31/2011 5:43 AM, John B. wrote:
On Sun, 30 Oct 2011 23:16:58 -0700, "Steve
wrote:


The reason
that it comes up is that I read about a new class of ULCCs
(UltraLargeCrudeCarriers -- Way big mutha oil tankers) that have 2
cycle diesel engines with NO transmission, clutch or reduction gears of
any sort. The drive shaft comes out the back of the engine and goes out
the back of the hull and the propeller is bolted directly to the end of
it No gears, no clutch, no nothing. The way that they reverse it is by
shutting of the engine and then restarting it BACKWARDS!!?! It is
designed to do this, I'm wondering if all 2 cycle engines will run
backwards or not? Inquiring minds want to know.

Bill

I am amazed that the engines are designed to be stopped, then restarted
backwards. This, I believe, would take at least some time on the larger
engines, but perhaps not. I have been on a lot of motor vessels in the open
sea, but none as large as I believe you are talking about. Starting and
stopping the engines would take too much time to do some of the delicate
maneuvering required using multiple props to get the vessel to do the
intended maneuver. I do not doubt that this may be the case on longer ships
that take a very long time to stop or turn or even slow down. I just can't
imagine that would be the safest and best way to maintain control over the
vessel, and to get it to respond in a timely and safe manner when
maneuvering. There is a lot of jockeying the throttles and gearing by the
captain during maneuvering a boat for docking, or negotiating tight spaces.
I'm wondering if the response times are adequate for the intended result.

I've spent probably more than 1,000 days on various boats in the open sea,
in the 150 - 250 foot class.

Steve

I think that you'll find that most of the larger ships (VLCC, the big
box boats, etc) are all direct drive reversing engines. I believe that
a combination of the giant size of pistons, rods, etc. means that they
can't be designed to run at very high revs, say 100 RPM perhaps, and
the size of any reversing gear and the power they would have to absorb
make the direct drive setup cheaper and less complicated to build.

Yout 150 - 250 ft. boats were something different and likely far more
maneuverable then the "big boats".

An interesting aside I read, was that using a box carrier like the
Emma Maersk it is cheaper to ship a container from China to a West
Coast port then the cost of freight for the box from the port to its
final distention inside the U.S. Obviously internal freight varies
with the distance delivered it does give a good picture of why these
big boats. (and incidentally, part of the reason for moving your
industry off shore)


--
John B.

I spent 3 years maintaining engines on a 92 foot ship, These engines had
a camshaft that could shifted so that a second set of cams could operate
the valves. And they had a distributor for the air starts. They were
made by Winton (sp).

And maneuvering the ship required some planning. Full speed on the
engines was 1200 to 1500 RPM. maneuvering speed was 500 to 600 RPM.
That was 1948 time frame so my memory on the RPMs my be not correct
on the details.

Bill K7NOM

On Mon, 31 Oct 2011 09:15:13 -0700, bill wrote:

On 10/31/2011 5:43 AM, John B. wrote:
On Sun, 30 Oct 2011 23:16:58 -0700, "Steve
wrote:


The reason
that it comes up is that I read about a new class of ULCCs
(UltraLargeCrudeCarriers -- Way big mutha oil tankers) that have 2
cycle diesel engines with NO transmission, clutch or reduction gears of
any sort. The drive shaft comes out the back of the engine and goes out
the back of the hull and the propeller is bolted directly to the end of
it No gears, no clutch, no nothing. The way that they reverse it is by
shutting of the engine and then restarting it BACKWARDS!!?! It is
designed to do this, I'm wondering if all 2 cycle engines will run
backwards or not? Inquiring minds want to know.

Bill

I am amazed that the engines are designed to be stopped, then restarted
backwards. This, I believe, would take at least some time on the larger
engines, but perhaps not. I have been on a lot of motor vessels in the open
sea, but none as large as I believe you are talking about. Starting and
stopping the engines would take too much time to do some of the delicate
maneuvering required using multiple props to get the vessel to do the
intended maneuver. I do not doubt that this may be the case on longer ships
that take a very long time to stop or turn or even slow down. I just can't
imagine that would be the safest and best way to maintain control over the
vessel, and to get it to respond in a timely and safe manner when
maneuvering. There is a lot of jockeying the throttles and gearing by the
captain during maneuvering a boat for docking, or negotiating tight spaces.
I'm wondering if the response times are adequate for the intended result.

I've spent probably more than 1,000 days on various boats in the open sea,
in the 150 - 250 foot class.

Steve

I think that you'll find that most of the larger ships (VLCC, the big
box boats, etc) are all direct drive reversing engines. I believe that
a combination of the giant size of pistons, rods, etc. means that they
can't be designed to run at very high revs, say 100 RPM perhaps, and
the size of any reversing gear and the power they would have to absorb
make the direct drive setup cheaper and less complicated to build.

Yout 150 - 250 ft. boats were something different and likely far more
maneuverable then the "big boats".

An interesting aside I read, was that using a box carrier like the
Emma Maersk it is cheaper to ship a container from China to a West
Coast port then the cost of freight for the box from the port to its
final distention inside the U.S. Obviously internal freight varies
with the distance delivered it does give a good picture of why these
big boats. (and incidentally, part of the reason for moving your
industry off shore)


--
John B.

I spent 3 years maintaining engines on a 92 foot ship, These engines had
a camshaft that could shifted so that a second set of cams could operate
the valves. And they had a distributor for the air starts. They were
made by Winton (sp).

And maneuvering the ship required some planning. Full speed on the
engines was 1200 to 1500 RPM. maneuvering speed was 500 to 600 RPM.
That was 1948 time frame so my memory on the RPMs my be not correct
on the details.

Bill K7NOM

Try
http://www.tugboatenthusiastsociety....ancient-01.htm

1200 - 1500 was really high speed for that type of engine :-) I worked
on a Gardener 6 cyl. that was supposed to have a max continuous rpm of
1500 but was set to run at 1,000 with about 500 RPM idle. I offered
to reset the governor but the Chinese guy that owned it said the boat
did 7 K so leave it alone :-)


--
John B.

On Mon, 31 Oct 2011 08:41:14 -0700, Paul Drahn
wrote:

On 10/29/2011 9:23 PM, Ed Huntress wrote:


"John G" wrote in message
. au...

Gardner has brought this to us :
On 29-Oct-2011 21:20, engineman wrote:
I'm wondering if all 2
cycle engines will run backwards or not?

Most can. The ignition timing will be off -- the spark will be late --
and the engine will not develop much power.

__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

Ship board diesels are commression ignition (just like other diesels)
and hence do not rely on ignition timing. (I believe)

--
John G.

The motorcycle hypothetical caused me not to reply initially, because
there are two issues the the ignition, as previously mentioned, and
the type of intake valve used.

Battery and spark-coil ignition, as the previous poster said, will be
off on timing but may allow it to run. Electronic ignition may be
closer. Magneto ignition probably won't allow it to run backwards at all
because the pulse to create the spark won't occur until well after TDC.

On the valves, reed-type or piston-port, yes. Rotary-valve, probably not.

I started a lot of model airplane engines backwards when I was a kid,
unintentionally. They had reed valves (my little Cox engines) or rotary
type (McCoy Red Head). My recollection of the McCoy, though, is that it
would start backwards, so it may have been fairly symmetrical. The Coxes
did it all the time, if you weren't careful.

Those engines were glow-plug ignition and, like compression ignition
engines, didn't care which way they were running from an ignition
standpoint.

Is anyone familiar with the old drag-saws used to buck up logs. I
remember the engine could be started either way, depending on the way
you spun the flywheel.

Paul
Or the motor buggy used by maintenance crews on the railway?
Gerry :-)}
London, Canada

Tim Wescott wrote:

(...)

There are some itty-bitty reed valve engines that run quite happily in
either direction -- in fact, a Cox 049 reedie will generally start the
opposite of the direction you flip it, when you're trying to flip it
forward. Flipping it backward, it generally starts in the same direction
as the flip. Go figure.

Ah! That explains why my long-lost 0.049 Cox 'Vette
always ran backwards! The recoil starter rotated
the wheels forward.

--Winston

"Gerald Miller" wrote


Is anyone familiar with the old drag-saws used to buck up logs. I
remember the engine could be started either way, depending on the way
you spun the flywheel.

Paul
Or the motor buggy used by maintenance crews on the railway?
Gerry :-)}
London, Canada

I saw a really interesting single cylinder engine in Round Top, Texas, the
world's largest yard sale. It was originally used for grinding corn, IIRC.
It had a belt that went to the grinder.

The motor was original, and had been running now for about a hundred years,
just not continuous. It has two exhaust valves. It has a governor with the
two spinning balls that controls one of the valves. When the rpm gets too
high, the governor kicks in, and a cam keeps one exhaust valve open, but the
spark still fires. When it does, it gives if a distinguishing sound firing
out through the open valve, and is called a popcorn machine, or something of
the sort.

Of course, you could buy a bag of kettle corn, which was doing a brisk
business. You could hear it from a distance, as it had a very unusual
sound.

Steve