"Cerumen" wrote in message
...

"Ted Bell" wrote in message
...
When it's very cold I have a hard time cranking my diesel. I was
wondering if I put Tilley wicks saturated in meths around the
injectors and lit them if it would warm up the injectors enough to
vaporize the fuel better. Anybody ever try it?

No but I have warmed a reluctant deisel with a blow lamp before now,
heat inlet manifold and then crank. Another tip is to cover, if you
can, the inlet port which can make the engine spin a lot faster,
remove the blockage and inertia helps to start it.


--
Chris, West Cork, Ireland.


If I've read it right a diesel compresses the air to a very great
extent. The compression heats the air so much that fuel self-ignites
when injected into the hot air. Even if it's very cold it's my
understanding the compressed air is still hot enough to ignite the fuel.
So it seems to me if the fuel doesn't ignite maybe it's because it's so
cold and thick that the injectors don't spray it in properly. Maybe just
dribbles of larger droplets that are reluctant to burn. So heating the
injectors seems like it would take care of that problem. Sort of the
same principle that a pressure diesel stove uses to pre-heat the fuel.
Meths don't burn all that hot so although it might blacken the paint I
can't see where it would damage the injector. I think I'll give it a go.
.. .

Thanks to all who responded.

I'm Ted Bell!

Ted Bell wrote:

If I've read it right a diesel compresses the air to a very great
extent. The compression heats the air so much that fuel self-ignites
when injected into the hot air. Even if it's very cold it's my
understanding the compressed air is still hot enough to ignite the fuel.
So it seems to me if the fuel doesn't ignite maybe it's because it's so
cold and thick that the injectors don't spray it in properly.

It is more common, particularly on engines well past their youth, that
compression is not as good as it should be. The result is that the
compressed air doesn't get hot enough quickly enough at low revs in
a cold engine block. This seems a likelier scenario than the fuel
being too viscous at low temperature to disperse properly.

Maybe just
dribbles of larger droplets that are reluctant to burn. So heating the
injectors seems like it would take care of that problem. Sort of the
same principle that a pressure diesel stove uses to pre-heat the fuel.
Meths don't burn all that hot so although it might blacken the paint I
can't see where it would damage the injector. I think I'll give it a go.

Many engines are fitted with electric glow-plug preheaters. I don't think
they heat the injectors, but part of the combustion chamber. On some
engines, electric heater coils are located within the air intake. This
is an easy option to retro-fit (unlike glowplugs which really need to
be designed in from the start), and Bukh, for instance, offer this option
and I can vouch for how well it works. They basically preheat the air, so
that it's already warmer before it gets heated by being compressed. The
result is that the compression heats the air up to an even higher
temperature, making it more likely that the engine will fire sooner.

I would recommend that if you want to have a go, it would be a better idea
to heat up the air intake than the injectors.

Ronald Raygun wrote in
. uk:

Many engines are fitted with electric glow-plug preheaters. I don't
think they heat the injectors, but part of the combustion chamber.

Glow plugs are situated in the path of the spray pattern of the injector,
usually in a pre-combustion chamber which not only makes the engine much
easier to start, but much quieter to run.

http://www.kenrockwell.com/190d/images/lvp.gif
Here's the precombustion chamber of a Mercedes Benz 190D diesel. The
glowplug is the gold pin right under the spray head. It heats red hot
just before the engine starts, causing the fuel to explode reliably as
soon as it is injected, by the injector directly above it. It continues
to glow, as does the grey resonator under it while the engine is running,
not by the electrical current, but by the last time the fuel exploded.

The explosion happens in the precombustion chamber and an immense
pressure pushes the explosion into the air charge down in the cylinder
through those tiny holes, maybe 1/8" diameter, in a radial pattern on top
of the piston to balance the pressure on the piston top. After 25 years
of constant use, my '73 220D sedan's little 57hp diesel piston had 5
little tracks across the top of the piston showing where the explosion
went by it at TDC on ever other stroke. I couldn't get over how small
these holes are and how clean they stayed all those years when we
overhauled it at about 250,000 miles. It really only needed new rings.

Notice in MB cars, the whole chamber screws out so it can be easily
replaced if it cracks under the pressure. Smart, very smart.

All this is done to reduce the compression necessary to start it cold and
run it QUIETLY in a nice car. It ran fine on vegetable oil going to
breakfast with my old friends, this very morning...(c;


Larry
--
Have a little fun in the checkout line....
Ask the nearest American, "Did you see the ICE
agents chasing those Mexicans out the back door?"
....Shortens that checkout line right up...(c;

"Ted Bell" wrote in news:eshhk2$mji$1
@aioe.org:

Even if it's very cold it's my
understanding the compressed air is still hot enough to ignite the
fuel.

As long as there is proper compression, you're absolutely right. Test
the compression on a COLD engine, not hot, to see if it has enough
pressure on ALL cylinders.

So it seems to me if the fuel doesn't ignite maybe it's because it's so
cold and thick that the injectors don't spray it in properly. Maybe
just
dribbles of larger droplets that are reluctant to burn.

Well, this sounds good but is very hard to achieve. If diesel fuel is
NOT properly "winterized" by mixing it with light elements, WAX CRYSTALS
form in the diesel fuel making it impossible to pump. It doesn't
"thicken", it turns to a SOLID! You can heat the whole fuel system and
keep it from waxing up. In boats, the problem is the cheapskate sailors
use so little fuel, they only buy it in SUMMER when it's not winterized,
which costs the fuel companies extra money. Winter comes, the tanks are
full of unwinterized diesel he "saved" by not burning it. It turns to
wax in the cold and the engine won't crank as it has no fuel...the fuel
system blocked by the wax until Spring. He's ****ed and needs someone to
blame.

What he SHOULD have done was to burn the tank dry before it got too cold
and refilled it in the Fall with WINTERIZED diesel fuel, which doesn't
turn to jelly in the cold. Cheapskate didn't. Hell, he never fills his
tanks and has water ingestion problems, too, storing it 1/4 full. Oh,
the WATER in the tanks he never fills ALSO causes fuel starvation as IT
freezes in the tanks, filters, low points of the lines, etc....another
problem easily fixed.

So heating the
injectors seems like it would take care of that problem. Sort of the
same principle that a pressure diesel stove uses to pre-heat the fuel.
Meths don't burn all that hot so although it might blacken the paint I
can't see where it would damage the injector. I think I'll give it a
go.

No, because he can't pump solid fuel into where the heated pump is as
it's waxed up in the lines. The cure is WINTERIZED DIESEL FUEL,
available after a certain date in that area. His tanks have summer
diesel fuel in them full of wax crystals....cloudy on cool days, solid on
cold.

Please don't light any open fires in the engine compartment with the
battery fumes, ok? We don't need any MORE excitement on boat newsgroups
than the usual groundings....


Larry
--
Have a little fun in the checkout line....
Ask the nearest American, "Did you see the ICE
agents chasing those Mexicans out the back door?"
....Shortens that checkout line right up...(c;

On Mon, 5 Mar 2007 11:48:05 -0500, "Ted Bell"
wrote:


If I've read it right a diesel compresses the air to a very great
extent. The compression heats the air so much that fuel self-ignites
when injected into the hot air. Even if it's very cold it's my
understanding the compressed air is still hot enough to ignite the fuel.
So it seems to me if the fuel doesn't ignite maybe it's because it's so
cold and thick that the injectors don't spray it in properly. Maybe just
dribbles of larger droplets that are reluctant to burn. So heating the
injectors seems like it would take care of that problem. Sort of the
same principle that a pressure diesel stove uses to pre-heat the fuel.
Meths don't burn all that hot so although it might blacken the paint I
can't see where it would damage the injector. I think I'll give it a go.
. .

Thanks to all who responded.

I'm Ted Bell!

I don't think heating the accessible parts of the injectors will do
much good - the nozzle is deep inside the head, and the body of the
injector passes through metal immersed in the cooling water, so very
little heat will make it to the injector nozzle.




--
Peter Bennett, VE7CEI Vancouver BC, Canada
peterbb4 (at) interchange.ubc.ca
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