primitives debate gasoline, diesel

[franksolich]

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=389x4509836

I dunno why my fellow alum keeps this bonfire in "General Discussion" on Skins's island; it seems more appropriate for the automotive forum over there.

And as God knows, the automotive forum over there needs some action.

burythehatchet  (1000+ posts)        Fri Nov-21-08 02:33 PM
Original message
 
What is the difference between gas and diesel?

and what is different in the combustion chambers of engines that use each type of fuel?

MookieWilson  (1000+ posts)      Fri Nov-21-08 02:36 PM
Response to Original message
 
2. Flash point of diesel is MUCH lower. Safet to handle, etc.

LostinVA  (1000+ posts)      Fri Nov-21-08 02:52 PM
Response to Reply #2
 
11. Yeah, it's the exact same thing as heating oil (just with a few additives)

You can put it in your oil tank for your furnace. I've put a few gallons in before myself.

As a non-expert on fuels, I have to ask.

Is this a safe, or wise, thing to do?

Winterblues  (1000+ posts)      Fri Nov-21-08 02:36 PM
Response to Original message
 
3. About $2.00 per gallon

phantom power  (1000+ posts)        Fri Nov-21-08 02:38 PM
Response to Original message

4. In a gasoline engine...

the fuel/air mixture has to be ignited with a spark-plug. In a diesel engine, the fuel/air mixture is ignited purely by temperature increase from adiabatic compression.

What's "diabetic compression"?  I reasonably assume the primitive misspelled it.

LostinVA  (1000+ posts)      Fri Nov-21-08 02:50 PM
Response to Reply #4
 
9. glowplugs

TheWraith  (1000+ posts)      Fri Nov-21-08 02:40 PM
Response to Original message
 
5. Diesel is a thicker, more simplistic type of fuel

It's easier to refine than gas, can be produced from a variety of sources, and provides better torque and fuel efficiency. It's also less prone to explosion than regular gas. However, it's rather prone to gelatinizing in low temperatures, making it difficult to use in northern climates, and traditionally it's contained a lot of sulfur, though that's been changing.

Doesn't adding something called "Rotella" to #2 diesel fuel convert it into #1 diesel fuel, thus making diesel suitable for Nebraska in winter?  I've noticed people around here do that a lot.

BobRossi (1000+ posts)      Fri Nov-21-08 02:40 PM
Response to Original message
 
6. I'll try.

Gasoline engines have low compression ratio combustion chambers, on the order of 8:1 whereas diesel engines are high compression ratio. > 10:1. Gas engines require a spark to ignite the air/fuel mix in the chamber, diesel engines relay on the mixture self-igniting due to the high compression. (All things heat up when under great pressure). Diesel fuel has a higher energy density than gasoline so in theory it is more efficient.

slackmaster  (1000+ posts)      Fri Nov-21-08 02:42 PM
Response to Original message
 
7. Diesel = bigger molecules, requires much higher compression

And no spark to make it go off once the correct temperature is reached.

Selatius  (1000+ posts)      Fri Nov-21-08 02:43 PM
Response to Original message
 
8. Diesel engines don't need spark plugs to ignite fuel that is injected into the chambers.

Petrol engines do need spark plugs. The high compression ratio in diesel engines is what causes the fuel to ignite. A side-effect of the high compression is better fuel economy, typically 30% or better compared to a petrol engine of the same size. It's one reason why now 50% of all cars sold in Europe are diesel-based. It's sensible to meet rigorous fuel efficiency standards in Europe.

LostinVA  (1000+ posts)      Fri Nov-21-08 02:51 PM
Response to Original message
 
10. The difference is I get 45-55 mpg with my VW

[Miss Mia]

I drive a diesel and I love it.  It's more fun to drive.  Today I did drive around in my boss' demo, a Tiguan with the 2.0T engine, and it's a peppy little ride.  I put it on my Christmas wish list.   

[Peter3_1]

4 GAL home heating oil plus 1 gsl kero. makes 5 gal of "diesel". Add some anti gel and some  head/ upper cyl lubricant, and it is every bit as useful. pERFECTLY SAFE. Vegetable/nut oil can be used as diesel too.



http://finance.yahoo.com/q/pr?s=synm

read here for the future of natural gas use.

Gasoline is much more volitale than diesel.  It wuill explode at very low tempatures with tghe correct fuel/air misture, but has about 20% less energy than diesel. It has a better flame front when it burns, and burns cooler.

[Chris]

I drive a diesel and I love it.  It's more fun to drive.  Today I did drive around in my boss' demo, a Tiguan with the 2.0T engine, and it's a peppy little ride.  I put it on my Christmas wish list.   

I want a VW with an Audi twin turbo, some fat wheels, and racing stripes.  Enough torque to turn the Beetle into a Pretzel.

[Peter3_1]

Yes, Chris, and after a few minuites of your loving attention, it would go BANG and run no more. 

[Carl]

They are more or less correct in their answers although some are reaching a bit.

A compression ratio much lower then 14:1 and you will need to have a lot of ether around to start it.
We do this for tractor pulling if turbocharged or multi turbocharged simply to keep the combustion pressures down and because the injection timing is so advanced....40 + degrees before TDC.
Gives a head gasket a fighting chance as boost pressures run from 80-200 psi depending.

Normal is around 16:1 with turbocharged engines sometimes slightly lower even for stock usage.

The usual thing to cut diesel fuel with in the north is kerosene,typically a 50/50 mix.
A diesel can run on straight kerosene but because it is more refined and thus a lighter fuel it has less BTUs/gallon so not as efficent or having the same power output.

[Chris]

Yes, Chris, and after a few minuites of your loving attention, it would go BANG and run no more. 

 

[franksolich]

They are more or less correct in their answers although some are reaching a bit.

Does this Rotella stuff do the same thing that kerosene does?

Man, that's expensive stuff, Rotella.

One day, when I was headed to town, the old guy asked me to pick him up a couple of gallons of it (Rotella), and gave me a twenty to buy it.  I thought probably a five would do it, but I was wrong.

There MUST be places that sell it, but I've never seen kerosene sold around here.

[Miss Mia]

Does this Rotella stuff do the same thing that kerosene does?

Man, that's expensive stuff, Rotella.

One day, when I was headed to town, the old guy asked me to pick him up a couple of gallons of it (Rotella), and gave me a twenty to buy it.  I thought probably a five would do it, but I was wrong.

There MUST be places that sell it, but I've never seen kerosene sold around here.

There's another additive you can use made by Power Service.  Basically it helps prevent the diesel fuel from gelling overnight in the cold weather.  Plus like my car has glowplugs to warm it up before I actually turn on the car.  If I lived somewhere that it got really cold, you can use a block heater on your engine as well. 

[Carl]

Does this Rotella stuff do the same thing that kerosene does?

Man, that's expensive stuff, Rotella.

One day, when I was headed to town, the old guy asked me to pick him up a couple of gallons of it (Rotella), and gave me a twenty to buy it.  I thought probably a five would do it, but I was wrong.

There MUST be places that sell it, but I've never seen kerosene sold around here.

Not sure Frank,the only thing I know of by that name is diesel engine oil by Shell.
They may use the name Rotella for a variety of diesel engine products.

As Mia said in her post we sell Power Service fuel suppliment for adding back the lubricity that has been lost as the sulpher has been removed.
It is very important in older off road engines using a Stanadyne (Roosa Master) or CAV rotary injection pump but also now with inline ones.
The GM and Ford diesel pickups of the 80s and 90s also used these pumps,don`t know about now,guessing they may be using more of a common rail system then a plunger pump.

Trans fluid or Marvel Mystery Oil will work fine too but the red color is a problem if found in a vehicle.
Those don`t do anything for the fuel gelling so would only be useful in warm areas and off road usage.
The Power Service fuel conditioner does both so is a preferred product.

Power Service also has a product called 911 and it will reliquify fuel that has gelled or waxed in the filter.
It is about the only thing I know except for a heater that will get one going again if it is dead.

There are two types of diesels since Mia also mentioned the glow plugs.
Those using them are considered indirect injection...they have a small area called a pre combustion chamber or pre cup off the the side of the main one at the top of the piston.
The glow plug is threaded into this area and the fuel is ingected there.
It flashes from the glow plug and then burns out and down into the cylinder.
They are less efficient then a direct injection one which injects the fuel directly into the bowl of the piston.

The glow plug makes it possible for an average motorist to start the diesel in the cold without having to have a block heater or use starting fluid.
Glow plugs and ether never should mix....very bad.

[Peter3_1]

amsoil makes additives, but I don't know about price?:

http://www.premiumdieseloil.com/additives

rotella seems to be a Shell product:

http://www.imakenews.com/rotella/e_article000158464.cfm?x=b3yWWCK,b2cHcqb5,w


Here's a test, for what it is worth:

http://www.johnfjensen.com/Diesel_fuel_additive_test.pdf

[Wineslob]

Rotella is a standard engine oil for diesel engines.
Most diesels have a C/R (compression ratio) of around 18-22:1 quite high and needed to auto combust (no sparkplugs). Most comsumer diesels have preheaters as was mentioned before. My buddys Dodge w/a Cummins has this option. Turn the key, let it tell you when it's ready to start, and away you go.
The engines are completely different from a gasoline engine. The internal pressures are very high. A "normal" 8:1 C/R gas engine will be around 140 psi. When I had a 11:1 C/R engine in my Camero the static (just starter cranking it) pressure was in the 215 psi (lbs) range. Now imagine almost double that. That they are built "beefy" is an understatement.

[Peter3_1]

And the reason the GM conversion of the small block 350 to diesel failed so badly. The engines just were too thinwalled to stand the pressures put on them, and, they were not that "powerful" an engine either.

[JohnnyReb]

And the reason the GM conversion of the small block 350 to diesel failed so badly. The engines just were too thinwalled to stand the pressures put on them, and, they were not that "powerful" an engine either.

150,000 trouble free miles on 2 of them.......but then, I didn't add "gas" to make them crank better, "transmission fluid" to clean the injectors, "fuel conditioners" for whatever reason, etc.. I bought clean fuel, serviced them on time and drove hell out of'em. I'd buy another if they still offered them.

Been around diesel engines all my life and loved them......that is until the government got to requiring all the B.S. they have to put on'em now. If it ain't broke, let the government take a whack at it.

[Thor]

Was it 1979 when GM first introduced the diesel engines?? I bought a vehicle that HAD a diesel in it when I test drove it. It drove nice, but I noticed a strange "rattle". Turns out that one of the main bearing holders had broken. It seems that this was a common issue in the 79 & 80 model GM diesels. I spoke with the dealership and we made an agreement. They would put a gas 350 Olds engine it and I would buy it. I was able to watch they guy rebuild that engine. He did an awesome job. Turns out that he rebuilt a 1969 Olds Rocket engine and did a couple of tweaks on it. I sure liked that car.

[Peter3_1]

Johnny, and I have 265,000 on my in line 6 Jeep Cherokee engine and never a major repair on it. Just because we know how to preserve an engine and get work out or it reliably, doesn't mean every one does.

The average guy / gal blew the old gas based diesels like a kid blows a runny nose.

[JohnnyReb]

Johnny, and I have 265,000 on my in line 6 Jeep Cherokee engine and never a major repair on it. Just because we know how to preserve an engine and get work out or it reliably, doesn't mean every one does.

The average guy / gal blew the old gas based diesels like a kid blows a runny nose.

Peter3_1, after owning the diesel '78 Olds cutlass, I got the diesel '82 Olds 98 and then the 6.2 liter '85 GMC 4-door dually pickup. The GMC pickup had 285,000 miles on it when it got totaled in a terrible wreck. It still didn't use oil and ran just fine, never had any problems with it. Before it was wrecked, I had already bought a '92 Ford diesel 4-door dually. The ford has over 450,000 miles on it now and needs it's first fuel injection pump. About the only complaint with the Ford I've got is that I couldn't keep glow plugs in it. I bought ovesized batteries (High amp) to use for jump starting heavy equipment and the dealer said that was what kept burning out the glow plugs...baloney. So for the last 350,000 miles I've just used starting fluid to crank it in the mornings....no problems.

I'm retired now and am driving a Chevy gasser pickup. I don't put the miles on them like I used to.     

[JohnnyReb]

It drove nice, but I noticed a strange "rattle".

That "rattle" is probably what got me my first Olds diesel. A customer ordered a plain jane Cutlass with a diesel. When it came in he wouldn't take it because it "rattled" and smoked. When people were paying a thousand dollars over sticker price to get a diesel Olds, I bought that one for a thousand off sticker. It had none of the fancy stuff and no one wanted it. It suited me to a "T".

The funny thing about my 2 olds. The Cutlass got 25 mpg around town and 28 mpg on the road. The Olds '98, much bigger with everything on it, got 28 mpg around town and 34 mpg on the road.

[Thor]

That "rattle" is probably what got me my first Olds diesel. A customer ordered a plain jane Cutlass with a diesel. When it came in he wouldn't take it because it "rattled" and smoked. When people were paying a thousand dollars over sticker price to get a diesel Olds, I bought that one for a thousand off sticker. It had none of the fancy stuff and no one wanted it. It suited me to a "T".

The funny thing about my 2 olds. The Cutlass got 25 mpg around town and 28 mpg on the road. The Olds '98, much bigger with everything on it, got 28 mpg around town and 34 mpg on the road.

I know that diesels rattle. This wasn't a common diesel "rattle" or "knock". Inspection showed it was the main bearing cap that had broken. I saw the broken main bearing cap. I'm pretty sure that the dealer already knew that this was the case. This was a common problem in the early GM 350 diesels. The gas engine that GM used just wasn't built well enough to handle that kind of compression. At least everything I've heard and read on the issue  goes back to that premise. I believe that it was 81/ 82 that they did a little redesigning and made them better.

[Peter3_1]

Johnny, when I was racing FF, by former brother in law was too, and used a GM diesel S/W as his tow vehicle. I used a Ford Bronco 2 gas v-6. On a long uphill on the way to Limerock CT, I breesed past him , and had my pit setup by the time he gor there.....

The Ford F-350 Diesel is the old INT'L Loadstar diesel, a workhorse and a powerful one too, and known to be long lived.  The earliest 350 diesel Fords still had the "loadstar" decals on the rocker covers.