If you don't have one, they are on sale with free shipping. I know Fein is
a superior quality tool but....


http://www.amazon.com/Fein-ASTXE-649...6?ie=UTF8&s=hi

Allen

Allen Roy wrote:
If you don't have one, they are on sale with free shipping. I know Fein is
a superior quality tool but....
http://www.amazon.com/Fein-ASTXE-649...6?ie=UTF8&s=hi


They're out of stock! Must have sold out right away at that price.
Forget it. Oh, well, guess I'll keep the Sawzall after all.
Andy

On Wed, 17 Jan 2007 21:30:04 -0500, "Allen Roy"
wrote:


If you don't have one, they are on sale with free shipping. I know Fein is
a superior quality tool but....


http://www.amazon.com/Fein-ASTXE-649...6?ie=UTF8&s=hi

I'd bet an awful lot that the price tag has *everything* to do with
the fact that it's designed to be used in an environment that must be
spark-free. All that stuff costs a lot of $$$, even the wrenches.

"Prometheus" wrote in message
...
On Wed, 17 Jan 2007 21:30:04 -0500, "Allen Roy"
wrote:


If you don't have one, they are on sale with free shipping. I know Fein
is
a superior quality tool but....


http://www.amazon.com/Fein-ASTXE-649...6?ie=UTF8&s=hi

I'd bet an awful lot that the price tag has *everything* to do with
the fact that it's designed to be used in an environment that must be
spark-free. All that stuff costs a lot of $$$, even the wrenches.

Inquiring minds want to know how carbon brushes and standard commutation
produce no sparks. The area is ventilated to cool it, rather than shielding
from sparks, so must be some exotic beryllium alloy on the commutator bars?

http://www.feinus.com/p/pdf/astx649_..._breakdown.pdf

"George" wrote in message
t...

"Prometheus" wrote in message


Inquiring minds want to know how carbon brushes and standard commutation
produce no sparks. The area is ventilated to cool it, rather than
shielding from sparks, so must be some exotic beryllium alloy on the
commutator bars?

I am convinced that it is magic that prevents sparks!

The same question can be asked and I did ask an Oldsmobile factory rep how
an electric fuel pump submerged in gasoline inside a fuel tank does not
cause an esplosion. He gave me a "totally lost" look.

The fuel pumps actually had gasoline flow through the center of the motor
and past the brushes. Old motors with worn out brushes were spotless
inside. I can understand how there would not be a problem when the motor
is submerged but what changes when you run out of gasoline?

"Leon" wrote in message
t...

"George" wrote in message
t...

"Prometheus" wrote in message


Inquiring minds want to know how carbon brushes and standard commutation
produce no sparks. The area is ventilated to cool it, rather than
shielding from sparks, so must be some exotic beryllium alloy on the
commutator bars?

I am convinced that it is magic that prevents sparks!

The same question can be asked and I did ask an Oldsmobile factory rep how
an electric fuel pump submerged in gasoline inside a fuel tank does not
cause an esplosion. He gave me a "totally lost" look.

The fuel pumps actually had gasoline flow through the center of the motor
and past the brushes. Old motors with worn out brushes were spotless
inside. I can understand how there would not be a problem when the motor
is submerged but what changes when you run out of gasoline?



Perhaps that's why the pump is located in a standpipe well?

"George" wrote in message
...



Perhaps that's why the pump is located in a standpipe well?



The electric pump is attached directly to the tank meter fuel line on one
end and has the primary tank sock/strainer attached to the other end. This
all hangs from the tank unit inside the fuel tank.

As long as the sock is submerged the pump pumps gasoline. The sock is no
longer submerged when you are very low on fuel. The motor/pump is above the
fuel level before the sock is above the fuel surface.

There must be some kind of ground to prevent arcing from the brushes but
when I cut one open to see how it worked I saw no sign of any thing except
worn out brushes. Clean as a whistle inside. Go figure. Its magic I tell
you. ;~)

"Leon" wrote in
t:


"George" wrote in message
...



Perhaps that's why the pump is located in a standpipe well?



The electric pump is attached directly to the tank meter fuel line on
one end and has the primary tank sock/strainer attached to the other
end. This all hangs from the tank unit inside the fuel tank.

As long as the sock is submerged the pump pumps gasoline. The sock is
no longer submerged when you are very low on fuel. The motor/pump is
above the fuel level before the sock is above the fuel surface.

There must be some kind of ground to prevent arcing from the brushes
but when I cut one open to see how it worked I saw no sign of any
thing except worn out brushes. Clean as a whistle inside. Go figure.
Its magic I tell you. ;~)


The part I liked was that, when the pressure dropped below some preset
point, it all shut down, clean as a whistle. And it cost some serious
change to get a new pump installed. But that fixed the problem, I'm told.

Good thing I trust my mechanic.

Patriarch

"Patriarch" wrote in message
. 136...


The part I liked was that, when the pressure dropped below some preset
point, it all shut down, clean as a whistle.

The older units would continue to run, out of fuel or not. That is what
mine would do. I replaced the one on my 1975 Olds Starfire befor going to
work at the Olds dealer. I was sorta woried about connecting all the wiring
back correctly although IIRC there were only 2 wires.


And it cost some serious
change to get a new pump installed.

A lot of trouble if the pump went bad and the tank was full of gasoline.
The tanks had to be dropped so that you could get to the top and remove the
tank unit.

They won't gift wrap it. That's gonna reduce its
popularity as a present.


Prometheus wrote:

I'd bet an awful lot that the price tag has *everything* to do with
the fact that it's designed to be used in an environment that must be
spark-free. All that stuff costs a lot of $$$, even the wrenches.

On Thu, 18 Jan 2007 14:07:12 GMT, "Leon"
wrote:


"George" wrote in message
et...

"Prometheus" wrote in message


Inquiring minds want to know how carbon brushes and standard commutation
produce no sparks. The area is ventilated to cool it, rather than
shielding from sparks, so must be some exotic beryllium alloy on the
commutator bars?

I am convinced that it is magic that prevents sparks!

The same question can be asked and I did ask an Oldsmobile factory rep how
an electric fuel pump submerged in gasoline inside a fuel tank does not
cause an esplosion. He gave me a "totally lost" look.

The fuel pumps actually had gasoline flow through the center of the motor
and past the brushes. Old motors with worn out brushes were spotless
inside. I can understand how there would not be a problem when the motor
is submerged but what changes when you run out of gasoline?


I believe this is because a 12 volt spark will not develop enough
energy to be hot enough to ignite the fuel or vapors.

That's why the easiest way to achieve intrinsically safe rating on
electrical stuff is to keep it below (IIRC) 24 volts.

Paul Franklin

"Allen Roy" wrote in message
...

If you don't have one, they are on sale with free shipping. I know Fein
is a superior quality tool but....


http://www.amazon.com/Fein-ASTXE-649...6?ie=UTF8&s=hi

Allen


I was shocked by the price tag for something that my recip. saw could do.
And yes when is the last time you had a sawzall spark on you? Being that
there is ventilation for the motor, one would have to assume that either it
is made of some real high end materials (gold wiring, some advanced
titanium, carbon fiber body) or that the price is in error. Also I would
like to find the concrete and cast iron cutting blades for it.


I could see this as being spark free..

http://www.amazon.com/Fein-MOT-6-18-...6?ie=UTF8&s=hi



And sorry to our Canadian friends, it can only be shipped in the U.S.

Allen

"Paul Franklin" wrote in message
...


I believe this is because a 12 volt spark will not develop enough
energy to be hot enough to ignite the fuel or vapors.

No, a spark is hot, light emitting hot.

"Allen Roy" wrote in message
...


I was shocked by the price tag for something that my recip. saw could
do. And yes when is the last time you had a sawzall spark on you?

The last time I turned it on.

In article ,
Leon wrote:

"George" wrote in message
et...

"Prometheus" wrote in message


Inquiring minds want to know how carbon brushes and standard commutation
produce no sparks. The area is ventilated to cool it, rather than
shielding from sparks, so must be some exotic beryllium alloy on the
commutator bars?

I am convinced that it is magic that prevents sparks!

The same question can be asked and I did ask an Oldsmobile factory rep how
an electric fuel pump submerged in gasoline inside a fuel tank does not
cause an esplosion. He gave me a "totally lost" look.

The fuel pumps actually had gasoline flow through the center of the motor
and past the brushes. Old motors with worn out brushes were spotless
inside. I can understand how there would not be a problem when the motor
is submerged but what changes when you run out of gasoline?



I'll take a shot at that one. A few shots actually. First, the
submersed electric fuel pumps that I am familiar with, used on some GM
vehicles, don't use brushes. Even if they did, gasoline requires oxygen
to burn (or explode, which is actually pretty rare except in movies & TV)
There is not enough 02 dissolved in gasoline to support combustion,
let alone explosion. I never really thought about it before, but with
fuel system design today, it would be pretty tough to get enough air
inside a gas tank to support a fire inside the tank. Of course,
someone could forget the gas cap, but even so, it would be unlikely.


--
Contentment makes poor men rich. Discontent makes rich men poor.
--Benjamin Franklin
Larry Wasserman - Baltimore, Maryland -

No.

"Paul Franklin" wrote in message I believe
this is because a 12 volt spark will not develop enough
energy to be hot enough to ignite the fuel or vapors.

That's why the easiest way to achieve intrinsically safe rating on
electrical stuff is to keep it below (IIRC) 24 volts.

Paul Franklin

() wrote in
:


I'll take a shot at that one. A few shots actually. First, the
submersed electric fuel pumps that I am familiar with, used on some GM
vehicles, don't use brushes. Even if they did, gasoline requires
oxygen to burn (or explode, which is actually pretty rare except in
movies & TV) There is not enough 02 dissolved in gasoline to support
combustion, let alone explosion. I never really thought about it
before, but with fuel system design today, it would be pretty tough to
get enough air inside a gas tank to support a fire inside the tank. Of
course, someone could forget the gas cap, but even so, it would be
unlikely.



If someone forgot the gas cap, a yellow light with a funny shape comes on
and a little bell dings... Well, at least on my mother's minivan. If
you look in the manual, I'm sure it says to take the vehicle to the
dealer soon when that light comes on. What's wrong with having a "check
gas cap" light?

Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

wrote in message
...
I'll take a shot at that one. A few shots actually. First, the
submersed electric fuel pumps that I am familiar with, used on some GM
vehicles, don't use brushes.

Brushless DC possible with modern electronics, of course. It'd be my
choice.

Just the blade while cutting something. The mototr is a given.


"Leon" wrote in message
. net...

"Allen Roy" wrote in message
...


I was shocked by the price tag for something that my recip. saw could
do. And yes when is the last time you had a sawzall spark on you?

The last time I turned it on.

On Thu, 18 Jan 2007 13:10:41 GMT, "George" wrote:


Inquiring minds want to know how carbon brushes and standard commutation
produce no sparks. The area is ventilated to cool it, rather than shielding
from sparks, so must be some exotic beryllium alloy on the commutator bars?

http://www.feinus.com/p/pdf/astx649_..._breakdown.pdf

Have to ask them, I was just taking this:

Product Description
From the Manufacturer
This is an electric hacksaw for cutting pipe and profile steel when a
spark free environment is required. The saw will cut pipes up to 24"
in diameter and profile steel up to 21 3/4" height and 11 1/2" width.
The saw blade needs 6 inches of clearance to make the cut. A pipe
clamp is also recommended for cutting pipes.

off the website at Amazon at face value.

wrote in message
...


I'll take a shot at that one. A few shots actually. First, the
submersed electric fuel pumps that I am familiar with, used on some GM
vehicles, don't use brushes.

Perhaps not now but they absolutely did back in the 70's and 80's. The
brushes wearing out was a common cause of failure.

Even if they did, gasoline requires oxygen
to burn (or explode, which is actually pretty rare except in movies & TV)
There is not enough 02 dissolved in gasoline to support combustion,
let alone explosion.

Something has to displace gasoline as the tank emptys. Most every one runs
out of gaoline at one time or another and the fuel pump was exposed to air
when the tank was low on fuel.


I never really thought about it before, but with
fuel system design today, it would be pretty tough to get enough air
inside a gas tank to support a fire inside the tank. Of course,
someone could forget the gas cap, but even so, it would be unlikely.

Air displaces gasoline as the tank emptys or the tank would collapse.
Unlikely, very true but what keeps the brushes from causing an explosion?

IT'S MAGIC.. ;~)

"George" wrote in message
t...

wrote in message
...
I'll take a shot at that one. A few shots actually. First, the
submersed electric fuel pumps that I am familiar with, used on some GM
vehicles, don't use brushes.

Brushless DC possible with modern electronics, of course. It'd be my
choice.

The motors inside the pumps indeed had brushes.

"Allen Roy" wrote in message
...
Just the blade while cutting something. The mototr is a given.



Cut through a nail with a bimetal blade while doing demolition. You often
get a spark.

"Puckdropper" wrote in message

If someone forgot the gas cap, a yellow light with a funny shape comes on
and a little bell dings... Well, at least on my mother's minivan. If
you look in the manual, I'm sure it says to take the vehicle to the
dealer soon when that light comes on. What's wrong with having a "check
gas cap" light?

Some do. My LeSabre has a message on the computer that reads "check gas
cap" Once you do, it takes about 15 starts for the code to go away.

Subaru has a "check engine" light. It appears to monitor the gas cap. Light
comes on, check gas cap. If cap is present and tight, replace with new one.
Light goes out. Never seen "check engine" light come on for any other
reason.

"Edwin Pawlowski" wrote in message
om...

"Puckdropper" wrote in message

If someone forgot the gas cap, a yellow light with a funny shape comes
on
and a little bell dings... Well, at least on my mother's minivan. If
you look in the manual, I'm sure it says to take the vehicle to the
dealer soon when that light comes on. What's wrong with having a "check
gas cap" light?

Some do. My LeSabre has a message on the computer that reads "check gas
cap" Once you do, it takes about 15 starts for the code to go away.

On Fri, 19 Jan 2007 19:52:23 -0500, "Edwin Pawlowski"
wrote:


"Puckdropper" wrote in message

If someone forgot the gas cap, a yellow light with a funny shape comes on
and a little bell dings... Well, at least on my mother's minivan. If
you look in the manual, I'm sure it says to take the vehicle to the
dealer soon when that light comes on. What's wrong with having a "check
gas cap" light?

Some do. My LeSabre has a message on the computer that reads "check gas
cap" Once you do, it takes about 15 starts for the code to go away.

2004 Ranger is smarter than I too.

Mark
(sixoneeight) = 618

On Sat, 20 Jan 2007 01:19:43 GMT, "CW" wrote:

Subaru has a "check engine" light. It appears to monitor the gas cap. Light
comes on, check gas cap. If cap is present and tight, replace with new one.
Light goes out. Never seen "check engine" light come on for any other
reason.

Bad emission sensors will do the same thing. ... and the light doesn't
go out until you get them replaced. Unfortunately, if you live in an
emission inspection county, you have to have them replaced in order to pass
inspection.




"Edwin Pawlowski" wrote in message
. com...

"Puckdropper" wrote in message

If someone forgot the gas cap, a yellow light with a funny shape comes
on
and a little bell dings... Well, at least on my mother's minivan. If
you look in the manual, I'm sure it says to take the vehicle to the
dealer soon when that light comes on. What's wrong with having a "check
gas cap" light?

Some do. My LeSabre has a message on the computer that reads "check gas
cap" Once you do, it takes about 15 starts for the code to go away.





+--------------------------------------------------------------------------------+

If you're gonna be dumb, you better be tough

+--------------------------------------------------------------------------------+

In article ,
Mark & Juanita wrote:
...snipped...
Bad emission sensors will do the same thing. ... and the light doesn't
go out until you get them replaced. Unfortunately, if you live in an
emission inspection county, you have to have them replaced in order to pass
inspection.


Or "fortunately" if you happen to breathe air LOL.


--
Make it as simple as possible, but no simpler.

Larry Wasserman - Baltimore Maryland -

In article ,
Leon wrote:

wrote in message
.. .


I'll take a shot at that one. A few shots actually. First, the
submersed electric fuel pumps that I am familiar with, used on some GM
vehicles, don't use brushes.

Perhaps not now but they absolutely did back in the 70's and 80's. The
brushes wearing out was a common cause of failure.

Even if they did, gasoline requires oxygen
to burn (or explode, which is actually pretty rare except in movies & TV)
There is not enough 02 dissolved in gasoline to support combustion,
let alone explosion.

Something has to displace gasoline as the tank emptys. Most every one runs
out of gaoline at one time or another and the fuel pump was exposed to air
when the tank was low on fuel.


I never really thought about it before, but with
fuel system design today, it would be pretty tough to get enough air
inside a gas tank to support a fire inside the tank. Of course,
someone could forget the gas cap, but even so, it would be unlikely.

Air displaces gasoline as the tank emptys or the tank would collapse.
Unlikely, very true but what keeps the brushes from causing an explosion?

IT'S MAGIC.. ;~)





The oldest submersed pump system I am familiar with is from the late
80s early 90s GM vehicles using throttle-body injection. Even
these systems manitained a constant fuel flow with a return line to
the fuel tank. As the return fuel is heated during its round trip,
pressure in the tank tends to rise due to increased fuel vapor
pressure. You have probably experienced the "poof" of escaping vapor
when removing a fuel cap. My understanding is that the pressure inside
the tank is largely from fuel vapor rather than air. The natural
tendency of the system over time is to exclude air from entering.

I do agree, though the idea of the electrically operated fuel pump
being inside the tank used to disturb me, however, either through
serendipity or design, I have yet to hear of a fuel tank fire caused
by an electric pump. And when you think about it (and I realize that
the current is limited to an extremely low value) the fuel gauge
system is electrically operated, with a sending unit inside the tank
that uses a contact that slides over a coil to make a variable
resistor. And that type of setup has been in use since before I was
born, let alone working on trucks.

Just as a possibly interesting story, I have been working in fleet
and mobile equipment maintenance for about 29 years now. I've seen a
few vehicles that caught on fire, some of them literally burning down
to the frame & chassis. I've only seen one fuel tank that had
combustion occur inside it without being damaged first. On this
particular vehicle, a pickup cab & chassis, a tech was doing some
welding in preparation of installing a utility body on the chassis. I
don't know exactly what happened, but there was a flashover of some
kind that caused a brief detonation of some sort inside the tank.
There was no external damage and no fire beyond the momentary "flash"
inside the tank. The interesting part is, that the tank "balooned"
somewhat as a result, but did not leak, and after the incident, it
held about 3 more gallons than when it was new!


--
Make it as simple as possible, but no simpler.

Larry Wasserman - Baltimore Maryland -

wrote in message
...





The oldest submersed pump system I am familiar with is from the late
80s early 90s GM vehicles using throttle-body injection.

This was 1975 GM carbutated. The X bodies in 1980 became some of the first
with fuel injection.


Even
these systems manitained a constant fuel flow with a return line to
the fuel tank. As the return fuel is heated during its round trip,
pressure in the tank tends to rise due to increased fuel vapor
pressure. You have probably experienced the "poof" of escaping vapor
when removing a fuel cap. My understanding is that the pressure inside
the tank is largely from fuel vapor rather than air. The natural
tendency of the system over time is to exclude air from entering.

Agreed, however there would surely be times that a cap would be left off and
at least a few times air would enter.



I do agree, though the idea of the electrically operated fuel pump
being inside the tank used to disturb me, however, either through
serendipity or design, I have yet to hear of a fuel tank fire caused
by an electric pump. And when you think about it (and I realize that
the current is limited to an extremely low value) the fuel gauge
system is electrically operated, with a sending unit inside the tank
that uses a contact that slides over a coil to make a variable
resistor. And that type of setup has been in use since before I was
born, let alone working on trucks.

IIRC the tank sending units had enclosed electrical for the float arm.



Just as a possibly interesting story, I have been working in fleet
and mobile equipment maintenance for about 29 years now. I've seen a
few vehicles that caught on fire, some of them literally burning down
to the frame & chassis. I've only seen one fuel tank that had
combustion occur inside it without being damaged first. On this
particular vehicle, a pickup cab & chassis, a tech was doing some
welding in preparation of installing a utility body on the chassis. I
don't know exactly what happened, but there was a flashover of some
kind that caused a brief detonation of some sort inside the tank.
There was no external damage and no fire beyond the momentary "flash"
inside the tank. The interesting part is, that the tank "balooned"
somewhat as a result, but did not leak, and after the incident, it
held about 3 more gallons than when it was new!

I was in the industry about 23 years and never saw a problem with tanks
either. I am missing something some where. I know that our factory rep
could not explaing how the fuel pump would not cause an explosion.

wrote:
In article ,
Leon wrote:
wrote in message
...
I'll take a shot at that one. A few shots actually. First, the
submersed electric fuel pumps that I am familiar with, used on some GM
vehicles, don't use brushes.
Perhaps not now but they absolutely did back in the 70's and 80's. The
brushes wearing out was a common cause of failure.

Even if they did, gasoline requires oxygen
to burn (or explode, which is actually pretty rare except in movies & TV)
There is not enough 02 dissolved in gasoline to support combustion,
let alone explosion.
Something has to displace gasoline as the tank emptys. Most every one runs
out of gaoline at one time or another and the fuel pump was exposed to air
when the tank was low on fuel.


I never really thought about it before, but with
fuel system design today, it would be pretty tough to get enough air
inside a gas tank to support a fire inside the tank. Of course,
someone could forget the gas cap, but even so, it would be unlikely.
Air displaces gasoline as the tank emptys or the tank would collapse.
Unlikely, very true but what keeps the brushes from causing an explosion?

IT'S MAGIC.. ;~)





The oldest submersed pump system I am familiar with is from the late
80s early 90s GM vehicles using throttle-body injection. Even
these systems manitained a constant fuel flow with a return line to
the fuel tank. As the return fuel is heated during its round trip,
pressure in the tank tends to rise due to increased fuel vapor
pressure. You have probably experienced the "poof" of escaping vapor
when removing a fuel cap. My understanding is that the pressure inside
the tank is largely from fuel vapor rather than air. The natural
tendency of the system over time is to exclude air from entering.

I'm not sure what that last sentence means, but I
suppose that it means that their is pressure in
the tank under normal operating conditions. That
is certainly true since at least the 1960's and
before fuel injection was common. The fuel cap is
made with a valve that prevents fumes from exiting
the tank but allows air to enter. This type of
cap prevents the tank from collapsing and also
results in water in the tank from cooling and
condensation of moisture from the air that enters.


I haven't a clue about the electrical operation of
the in tank pump. But even with a supposedly
empty tank (engine stops running) thee will be
enough gasoline to create a mixture of gasoline
and oxygen that is too rich to burn.

Before any one starts arguing, I and everyone know
that explosions and fires do occur around gas
tanks. But those occur when a tank ruptures, a
spark or open fire is at the mouth of the filling
hole, or a very small amount of gas is in the tank
when it is welded; all of those can provide at
least a pocket of gas/oxygen mixture that will burn.

"George E. Cawthon" wrote in message

I haven't a clue about the electrical operation of the in tank pump. But
even with a supposedly empty tank (engine stops running) thee will be
enough gasoline to create a mixture of gasoline and oxygen that is too
rich to burn.

Before any one starts arguing, I and everyone know that explosions and
fires do occur around gas tanks. But those occur when a tank ruptures, a
spark or open fire is at the mouth of the filling hole, or a very small
amount of gas is in the tank when it is welded; all of those can provide
at least a pocket of gas/oxygen mixture that will burn.

Too rich to burn is real, but with all the possibilities...tough to figure.

Do know that fuelling accidents involving vapor pressure in gas tanks are
the reason we have to have diesel ambulances now. Can't use the "200
treatment" phrase any more- 100% oxygen 100 mph- because they just never
can get there. Used to be a bennie on a rural run.

On Fri, 19 Jan 2007 22:34:19 -0700, Leon wrote
(in article ):



I do agree, though the idea of the electrically operated fuel pump
being inside the tank used to disturb me, however, either through
serendipity or design, I have yet to hear of a fuel tank fire caused
by an electric pump. And when you think about it (and I realize that
the current is limited to an extremely low value) the fuel gauge
system is electrically operated, with a sending unit inside the tank
that uses a contact that slides over a coil to make a variable
resistor. And that type of setup has been in use since before I was
born, let alone working on trucks.

IIRC the tank sending units had enclosed electrical for the float arm.

Not for Ford at least. The float arm ran through a slot directly to the wiper
arm and resistor winding.

-BR

"Bruce" wrote in message ...
On Fri, 19 Jan 2007 22:34:19 -0700, Leon wrote
(in article ):



I do agree, though the idea of the electrically operated fuel pump
being inside the tank used to disturb me, however, either through
serendipity or design, I have yet to hear of a fuel tank fire caused
by an electric pump. And when you think about it (and I realize that
the current is limited to an extremely low value) the fuel gauge
system is electrically operated, with a sending unit inside the tank
that uses a contact that slides over a coil to make a variable
resistor. And that type of setup has been in use since before I was
born, let alone working on trucks.

IIRC the tank sending units had enclosed electrical for the float arm.

Not for Ford at least. The float arm ran through a slot directly to the
wiper
arm and resistor winding.


GM did and or does have the round float arm make a 90 degree turn and go
straight into a small sealed up housing.

Leon wrote:
wrote in message
...
I'll take a shot at that one. A few shots actually. First, the
submersed electric fuel pumps that I am familiar with, used on some GM
vehicles, don't use brushes.

Perhaps not now but they absolutely did back in the 70's and 80's. The
brushes wearing out was a common cause of failure.

Even if they did, gasoline requires oxygen
to burn (or explode, which is actually pretty rare except in movies & TV)
There is not enough 02 dissolved in gasoline to support combustion,
let alone explosion.

Something has to displace gasoline as the tank emptys. Most every one runs
out of gaoline at one time or another and the fuel pump was exposed to air
when the tank was low on fuel.


I never really thought about it before, but with
fuel system design today, it would be pretty tough to get enough air
inside a gas tank to support a fire inside the tank. Of course,
someone could forget the gas cap, but even so, it would be unlikely.

Air displaces gasoline as the tank emptys or the tank would collapse.
Unlikely, very true but what keeps the brushes from causing an explosion?

The mixture of gasoline fumes and oxygen would be
too rich to explode even if the car ran out of
gasoline.

IT'S MAGIC.. ;~)


No, just basic chemistry.

"George E. Cawthon" wrote in message
news
The mixture of gasoline fumes and oxygen would be too rich to explode even
if the car ran out of gasoline.


So the car sits with the cap off for a week or two and someone gets in to
start the car.

There is more to it than a hopefully too rich mixture. Out of millions of
cars with this set up there are going to be a many chances offer the years
for many of them to have the right mixture.

On Thu, 18 Jan 2007 21:32:23 -0500, "Allen Roy"
wrote:


"Allen Roy" wrote in message
...

If you don't have one, they are on sale with free shipping. I know Fein
is a superior quality tool but....


http://www.amazon.com/Fein-ASTXE-649...6?ie=UTF8&s=hi

Allen


I was shocked by the price tag for something that my recip. saw could do.
And yes when is the last time you had a sawzall spark on you? Being that
there is ventilation for the motor, one would have to assume that either it
is made of some real high end materials (gold wiring, some advanced
titanium, carbon fiber body) or that the price is in error. Also I would
like to find the concrete and cast iron cutting blades for it.


I could see this as being spark free..

http://www.amazon.com/Fein-MOT-6-18-...6?ie=UTF8&s=hi



And sorry to our Canadian friends, it can only be shipped in the U.S.

Will your recip saw take a 37 inch blade for cutting over 20 inches of
structural steel?

As for the concrete and cast iron blades, it took me about 30 seconds
of searching to find sources--google "fein hacksaw blades" and you'll
get a link to the part numbers, google the part numbers and you'll get
links to suppliers. The short (20 inch) concrete blade is over 70
bucks.

And there's no indication on the Fein site that either saw is "spark
free".

The price appears to be because this is a honking big saw whose small
blades are about the same size as the biggest blades for a Sawzall,
and it's not intended to cut steel once in a while, it's intended to
cut it all dfay every day.

In article ,
says...

"George E. Cawthon" wrote in message
news
The mixture of gasoline fumes and oxygen would be too rich to explode even
if the car ran out of gasoline.


So the car sits with the cap off for a week or two and someone gets in to
start the car.

There is more to it than a hopefully too rich mixture. Out of millions of
cars with this set up there are going to be a many chances offer the years
for many of them to have the right mixture.



You know, this just cries out, "Mythbusters"