Proping Question

People will say it is technically impossible, but I think it is
wishful
thinking. An engine may not run backwards very well,

During World War II (really!) I worked on a farm in Concord, Mass.
There was a great steel-wheeled tractor that was started with a hand
crank. One time the tractor backfired while the lad was spinning the
crank, and the engine started running backwards. He jumped aboard
and
had a great time wheeling it around the yard, one speed forward and
three in reverse. Blue skies! -- Dan Ford

That was a Diesel engine, correct?

My great uncle Ern was nearly killed by a Model T Ford that he
cranked up
and the engine backfired and ran backward. 'Course, that guy was
nearly
killed so many times...
--
Waddling Eagle
World Famous Flight Instructor

A Model T will not run backwards. Even if it did run backwards it
would in
no way would put your life in danger.

The Model T was notorious for running backwards momentarily and causing
the crank to hit people in the face or it would break an arm. Ern was
knocked unconscious and suffered a broken nose.

It will not run continuously backwards, but it will run for a stroke or
two, just enough to hit you hard.

That is called "kick back" and isn't "running backward" at all.

Matt

Technically true. But "kick back" also makes a propeller a very effective
finger remover.

From what I have heard those old Model T Fords were notorious; although I do
not know how much was a result of people advancing the spark in the hope of
getting the engine to start, or how much was due to overall timing being out
of adjustment such that the markings on the spark advance control were no
longer accurate.

What makes that almost on topic is the fact that magnetos can also be out of
timing for various reasons, including wear of the points and/or the internal
cam followers, and that a failure of the impulse coupling(s) can move the
timing from after TDC to before TDC during the starting sequence. :-(

Actually, this has been a very imformative thread. For example, I had never
known the mechanism by which a four cycle engine can diesel backward beyond
a single kick--even though I have seen older automotive engines do so for a
half dozen strokes!

Peter

"Peter Dohm" wrote

Actually, this has been a very imformative thread. For example, I had
never
known the mechanism by which a four cycle engine can diesel backward
beyond
a single kick--even though I have seen older automotive engines do so for
a
half dozen strokes!


I had an older Oldsmobile that would diesel after the ignition was turned
off, sometimes for 2 minutes or more.

Whether it was running backwards, I don't know. I never thought to look for
that, and I don't own it anymore.
--
Jim in NC

On May 17, 9:00 pm, "Dave Stadt" wrote:
"C J Campbell" wrote in messagenews:2007051720300843658-christophercampbell@hotmailcom...





On 2007-05-17 14:59:44 -0700, "Capt. Geoffrey Thorpe" The Sea Hawk at
wow way d0t com said:

"Cubdriver" usenet AT danford DOT net wrote in message
. ..
On Wed, 16 May 2007 22:00:14 -0700, C J Campbell
wrote:

People will say it is technically impossible, but I think it is wishful
thinking. An engine may not run backwards very well,

During World War II (really!) I worked on a farm in Concord, Mass.
There was a great steel-wheeled tractor that was started with a hand
crank. One time the tractor backfired while the lad was spinning the
crank, and the engine started running backwards. He jumped aboard and
had a great time wheeling it around the yard, one speed forward and
three in reverse. Blue skies! -- Dan Ford

That was a Diesel engine, correct?

My great uncle Ern was nearly killed by a Model T Ford that he cranked up
and the engine backfired and ran backward. 'Course, that guy was nearly
killed so many times...
--
Waddling Eagle
World Famous Flight Instructor

A Model T will not run backwards. Even if it did run backwards it would in
no way would put your life in danger.- Hide quoted text -

- Show quoted text -

Running backwards for any length of time given the timing of the
spark. Usually you would expect the spark between 8-15 degress past
TDC (to allow the rod to move out and be ready to push down). if it
ran backwards, each ignition would be working against the engine.

-Robert

"Robert M. Gary" wrote

Running backwards for any length of time given the timing of the
spark. Usually you would expect the spark between 8-15 degress past
TDC (to allow the rod to move out and be ready to push down). if it
ran backwards, each ignition would be working against the engine.

Are you saying that a Model-T is timed at 8-15 degrees past Top Dead
Center?

I hope so, because that sure is not reality for modern engines.
--
Jim in NC

"C J Campbell" wrote in message
news:2007051806363950073-christophercampbell@hotmailcom...
On 2007-05-17 21:00:36 -0700, "Dave Stadt" said:


"C J Campbell" wrote in message
news:2007051720300843658-christophercampbell@hotmailcom...
On 2007-05-17 14:59:44 -0700, "Capt. Geoffrey Thorpe" The Sea Hawk at
wow way d0t com said:

"Cubdriver" usenet AT danford DOT net wrote in message
...
On Wed, 16 May 2007 22:00:14 -0700, C J Campbell
wrote:

People will say it is technically impossible, but I think it is
wishful
thinking. An engine may not run backwards very well,

During World War II (really!) I worked on a farm in Concord, Mass.
There was a great steel-wheeled tractor that was started with a hand
crank. One time the tractor backfired while the lad was spinning the
crank, and the engine started running backwards. He jumped aboard and
had a great time wheeling it around the yard, one speed forward and
three in reverse. Blue skies! -- Dan Ford

That was a Diesel engine, correct?

My great uncle Ern was nearly killed by a Model T Ford that he cranked
up
and the engine backfired and ran backward. 'Course, that guy was nearly
killed so many times...
--
Waddling Eagle
World Famous Flight Instructor

A Model T will not run backwards. Even if it did run backwards it would
in
no way would put your life in danger.

The Model T was notorious for running backwards momentarily and causing
the crank to hit people in the face or it would break an arm. Ern was
knocked unconscious and suffered a broken nose.

It will not run continuously backwards, but it will run for a stroke or
two, just enough to hit you hard.
--
Waddling Eagle
World Famous Flight Instructor

Funny, I have been driving one for near 10 years and have never heard such a
thing. If your head is so low as to get hit by the crank you have much
bigger problems to deal with or the guy was less than 3' tall. The crank
has a ratchet and will free wheel if the engine pops backwards.

"Morgans" wrote in message
news

"Robert M. Gary" wrote

Running backwards for any length of time given the timing of the
spark. Usually you would expect the spark between 8-15 degress past
TDC (to allow the rod to move out and be ready to push down). if it
ran backwards, each ignition would be working against the engine.

Are you saying that a Model-T is timed at 8-15 degrees past Top Dead
Center?

I hope so, because that sure is not reality for modern engines.
--
Jim in NC

They have manual spark advance. At start up and full retard you are at TDC
give or take a couple of degrees.

The crank has a ratchet and will
free wheel if the engine pops backwards.

How would that work? The engine going backwards against the crank
imparts the same (direction) force as the crank going forwards against a
recalcitrant engine. That would freewheel too, defeating the purpose.

Jose
--
There are two kinds of people in the world. Those that just want to
know what button to push, and those that want to know what happens when
they push the button.
for Email, make the obvious change in the address.

Jose wrote:
The crank has a ratchet and will
free wheel if the engine pops backwards.

How would that work? The engine going backwards against the crank
imparts the same (direction) force as the crank going forwards against a
recalcitrant engine. That would freewheel too, defeating the purpose.

Most hand cranks (I haven't seen a Model T lately, but on old tractors
and such) had a cam design such that the crank handle would turn the
crank shaft only in one direction. If the crank shaft tried to drive
the crank handle (as during a kick-back), it would spit the crank handle
forward and disengage it.

It is like the screw heads you see on some bathroom stalls where the
slot in the screw head has ramps behind it on opposite sides such that
you can tighten with a normal screw driver, but you can't easily remove
it with a normal screw driver.

Matt

Funny, I have been driving one for near 10 years and have never heard such a
thing. If your head is so low as to get hit by the crank you have much
bigger problems to deal with or the guy was less than 3' tall. The crank
has a ratchet and will free wheel if the engine pops backwards.- Hide quoted text -

- Show quoted text -

Sorry Dave,

That (almost) can't be correct. My 1916 Model -T as did all the other
hand cranked Model-T's I am aware of do have clutch on the crank. But
it will only disengage the crank when the engine fires forward. If the
driver forgets to retard the timing or the timing is off it is very
possible for it to back fire and the crank will spin backwards. Once
the crank starts spinning backward and the engine slows it clutch will
disengage the crank but not until it has either bruised the back of
you hand (if you did it right) or broken your arm (did it wrong). My
grandfather taught me to always hold the crank with an open hand
(don't put you thumb over it) So that it would throw your hand clear
if this happened. As for the "almost" part above I am sure there were
all kinds of creative inventions to prevent this from happening.
Perhaps your Model T has a non-standard clutch or starting device on
it.

Jacking up the left rear wheel doesn't hurt anything either if its
cold. But that is another topic.

Brian

Matt Whiting wrote:
Jose wrote:
The crank has a ratchet and will
free wheel if the engine pops backwards.

How would that work? The engine going backwards against the crank
imparts the same (direction) force as the crank going forwards against
a recalcitrant engine. That would freewheel too, defeating the purpose.

Most hand cranks (I haven't seen a Model T lately, but on old tractors
and such) had a cam design such that the crank handle would turn the
crank shaft only in one direction. If the crank shaft tried to drive
the crank handle (as during a kick-back), it would spit the crank handle
forward and disengage it.

Oops, part of above is incorrect. The handle will disengage only if the
crank drives if forward as when the engine starts, not backwards!

Matt