Why is tractor's Diesel instead of gas?
- Thread starter JohnBoy45
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Bird
Epic Contributor
Re: Why is tractor\'s Diesel instead of gas?
Nope, Terry, not all tractors are diesel powered. There are still lots of older tractors, perhaps most commonly the Fords and Farmalls but some John Deere and several others as well, that are gasoline powered. And some are propane powered. Someone else will have to tell you which newer ones, if any, are gasoline powered.
As to why most are diesel now, I can't say for sure. I'd imagine it's because of longer life, more power or torque at lower RPM, less maintenance (except for oil changes), lower cost of diesel (in the past), etc. I'm old enough to remember when the vast majority of trucks on the road were gasoline powered, but now many big trucks do you see now-a-days with a gasoline engine?
Nope, Terry, not all tractors are diesel powered. There are still lots of older tractors, perhaps most commonly the Fords and Farmalls but some John Deere and several others as well, that are gasoline powered. And some are propane powered. Someone else will have to tell you which newer ones, if any, are gasoline powered.
As to why most are diesel now, I can't say for sure. I'd imagine it's because of longer life, more power or torque at lower RPM, less maintenance (except for oil changes), lower cost of diesel (in the past), etc. I'm old enough to remember when the vast majority of trucks on the road were gasoline powered, but now many big trucks do you see now-a-days with a gasoline engine?
TonyV
Silver Member
Re: Why is tractor\'s Diesel instead of gas?
I agree with Bird. Diesel engines provide more torque, and are longer lasting. But come to think of it, my old 1952 Ford 8N that I traded in was gas powered, ran great, and never had an engine rebuild. Its funny though...as much as I enjoy my new tractor, I find myself missing that old Ford...sorta the way one misses that first car that they had.
....Tony
I agree with Bird. Diesel engines provide more torque, and are longer lasting. But come to think of it, my old 1952 Ford 8N that I traded in was gas powered, ran great, and never had an engine rebuild. Its funny though...as much as I enjoy my new tractor, I find myself missing that old Ford...sorta the way one misses that first car that they had.
....Tony
Re: Why is tractor\'s Diesel instead of gas?
Terry43,
There are still a lot of gas powered tractors out there. the advantage of diesel is strong low-end torque. Two advantages of high low end torque: lower RPMs equal longer engine life and better pulling power at low speeds/RPMs. Although peak torque is a nice spec, what is also important is that the engine torque curve be flat across a good range of rpms so that the engine has a wider working range (i.e without requiring constant transmission shifts).
Good low end torque can be found in a gas engine. The Ford straight six was famous for its "torquey-ness" and was used for years in pickups and other vehicles.
VA_Joe
Terry43,
There are still a lot of gas powered tractors out there. the advantage of diesel is strong low-end torque. Two advantages of high low end torque: lower RPMs equal longer engine life and better pulling power at low speeds/RPMs. Although peak torque is a nice spec, what is also important is that the engine torque curve be flat across a good range of rpms so that the engine has a wider working range (i.e without requiring constant transmission shifts).
Good low end torque can be found in a gas engine. The Ford straight six was famous for its "torquey-ness" and was used for years in pickups and other vehicles.
VA_Joe
RobertN
Super Member
Re: Why is tractor\'s Diesel instead of gas?
Diesel has more BTU per unit than gas. You can get more work out of a gallon of diesel than a gallon of gasoline.
Diesel engines have a broad, flat torque curve typically, and make that torque at lower rpms. Gas engines tend to be "peaky" on the torque curve, making best power in a small rpm range. That's why you can lug a diesel, but not a gas engine(not good to lug either engine though).
A gas engine can be made to have a wide torque curve, and last a long time. My Farmall-A is 22hp, and has a pretty flat curve. But, it is nearly twice the displacement of my similar powered Kubota. And, since diesel has more btu than gas, the Kubota gets better fuel economy than the Farmall. The Farmall engine, like the Ford 8N engine mentioned in this thread, last a long time. A lot of that has to do with them being low rpm engines. Big bore, long stroke, heavy crank and flywheel. That is what gives them thier power, but also holds the rpms down; you don't want to spin all that weight up fast.
Bird mentioned many trucks even used to be gas engines. The move away from that was the flatter torque curve with better economy. And, more power could be had as trucks grew in size and load. As an example, the last fire engine I worked off of, was 350hp, with about 1400ft/lb torque. It would be easy to get 350hp out of a big-block V8. But, try to get big torque numbers like that. You would need a HUGE gas enigne. The Cummins in the fire engine was 8.9 litre, or about 530ci. Lots of gas engines can be built in the 500ci range with lots more than 350hp. But, they will not have the hgh torque numbers. And, they will rev higher to get the HP and torque, resulting in shorterr relative engine life. And, fuel economy under load will be terrible.
Diesel has more BTU per unit than gas. You can get more work out of a gallon of diesel than a gallon of gasoline.
Diesel engines have a broad, flat torque curve typically, and make that torque at lower rpms. Gas engines tend to be "peaky" on the torque curve, making best power in a small rpm range. That's why you can lug a diesel, but not a gas engine(not good to lug either engine though).
A gas engine can be made to have a wide torque curve, and last a long time. My Farmall-A is 22hp, and has a pretty flat curve. But, it is nearly twice the displacement of my similar powered Kubota. And, since diesel has more btu than gas, the Kubota gets better fuel economy than the Farmall. The Farmall engine, like the Ford 8N engine mentioned in this thread, last a long time. A lot of that has to do with them being low rpm engines. Big bore, long stroke, heavy crank and flywheel. That is what gives them thier power, but also holds the rpms down; you don't want to spin all that weight up fast.
Bird mentioned many trucks even used to be gas engines. The move away from that was the flatter torque curve with better economy. And, more power could be had as trucks grew in size and load. As an example, the last fire engine I worked off of, was 350hp, with about 1400ft/lb torque. It would be easy to get 350hp out of a big-block V8. But, try to get big torque numbers like that. You would need a HUGE gas enigne. The Cummins in the fire engine was 8.9 litre, or about 530ci. Lots of gas engines can be built in the 500ci range with lots more than 350hp. But, they will not have the hgh torque numbers. And, they will rev higher to get the HP and torque, resulting in shorterr relative engine life. And, fuel economy under load will be terrible.
Bird
Epic Contributor
Re: Why is tractor\'s Diesel instead of gas?
Tony, my first tractoring experience was with a John Deere L in the early '50s. Dad said it was supposed to be rated at 11hp but spent its whole life left out in the weather and apparenlty had been used hard before he bought it, so he did have the engine overhauled on it. Like a lot of small tractors, there were things it couldn't pull, but it would sure spin its wheels trying. /forums/images/graemlins/laugh.gif
Tony, my first tractoring experience was with a John Deere L in the early '50s. Dad said it was supposed to be rated at 11hp but spent its whole life left out in the weather and apparenlty had been used hard before he bought it, so he did have the engine overhauled on it. Like a lot of small tractors, there were things it couldn't pull, but it would sure spin its wheels trying. /forums/images/graemlins/laugh.gif
Dargo
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Re: Why is tractor\'s Diesel instead of gas?
Hey Mr. Bird, I have several old (relative term) farmers around here that used older gas powered tractors on their small farms up until bout 10 years ago. According to them, it will now only take a few seasons to make up the difference in price (between the gas engine and diesel engine) from fuel useage. A very wise old (not relative term - he is in his upper 80's) neighbor told me that his gas powered tractors are now only worth something to someone who wants to collect them. He said that nobody can afford to actually operate a very strong gas powered tractor with fuel prices reaching $3.00 per gallon.
He told me that with 12 hours in the field on a gas tractor that has around 60 hp, he will burn nearly 40 gallons of gas. That's roughly $100 a day in gas! With the same hp diesel tractor, he burns around 16 gallons of fuel. That's $40 per day assuming the same cost for fuel. It doesn't take too many $60 dollar days to get the old gas powered tractor permanently parked. Also, even though he is a really laid back old fella, just try to tell him that it costs as much to keep up with a diesel engine as it does a gas engine. First, you'd get a look like you've escaped from the looney bin, then you'll get a lecture on 60 years worth of hands on experience telling you otherwise. /forums/images/graemlins/tongue.gif
Even though that is what he grew up with, and loved, he bluntly states that gasoline tractors are definitely a relic of the past.
Hey Mr. Bird, I have several old (relative term) farmers around here that used older gas powered tractors on their small farms up until bout 10 years ago. According to them, it will now only take a few seasons to make up the difference in price (between the gas engine and diesel engine) from fuel useage. A very wise old (not relative term - he is in his upper 80's) neighbor told me that his gas powered tractors are now only worth something to someone who wants to collect them. He said that nobody can afford to actually operate a very strong gas powered tractor with fuel prices reaching $3.00 per gallon.
He told me that with 12 hours in the field on a gas tractor that has around 60 hp, he will burn nearly 40 gallons of gas. That's roughly $100 a day in gas! With the same hp diesel tractor, he burns around 16 gallons of fuel. That's $40 per day assuming the same cost for fuel. It doesn't take too many $60 dollar days to get the old gas powered tractor permanently parked. Also, even though he is a really laid back old fella, just try to tell him that it costs as much to keep up with a diesel engine as it does a gas engine. First, you'd get a look like you've escaped from the looney bin, then you'll get a lecture on 60 years worth of hands on experience telling you otherwise. /forums/images/graemlins/tongue.gif
Even though that is what he grew up with, and loved, he bluntly states that gasoline tractors are definitely a relic of the past.
Buck
Platinum Member
Re: Why is tractor\'s Diesel instead of gas?
If that is the case, makes me wonder why more cars aren't diesel.
If that is the case, makes me wonder why more cars aren't diesel.
beenthere
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Re: Why is tractor\'s Diesel instead of gas?
Maybe speed, weight of the engine, and smell of the diesel /forums/images/graemlins/confused.gif /forums/images/graemlins/tongue.gif
Maybe speed, weight of the engine, and smell of the diesel /forums/images/graemlins/confused.gif /forums/images/graemlins/tongue.gif
DocHeb
Veteran Member
Re: Why is tractor\'s Diesel instead of gas?
Add noise, difficulty finding diesel, and the smell that never comes off your shoes from walking near the pump and stepping on the prior spills.
Add noise, difficulty finding diesel, and the smell that never comes off your shoes from walking near the pump and stepping on the prior spills.