How much would a good gasoline motor cost compared to a diesel?

[MossRoad]

The topic of making a swap to gasoline equipment comes up occasionally mostly because of recent emissions equipment. A Kohler air cooled motor and a diesel is a far cry from the same thing. How much would making a gas motor with comparable durability as a diesel cost in comparison? Likely features would include a cast iron block, liquid cooled, lower rpm more toque than the average gasser, quieter, than the average gasser, and fuel injected. I知 thinking building a good gasser wouldn稚 be as big of a cost savings as some claim.

It's not that hard. Take a look at a 70's International 2500b, available with gas or diesel engines. Compare the specs. Very similar using the exact same transmissions. I don't know how much longer the diesel engine would last compared to the gas engine. My gas version had well over 4000 hours when I bought it with the hour meter broken. I worked it hard for a few years then light for about 7 more. So maybe 1000 hours more. It was still running strong when we got rid of it.

And lets face it, HP is HP and torque is torque. Doesn't matter what's making the HP or torque, if the numbers are the same, they are the same. A diesel will hold the torque curve longer than a gas engine in general, so that's one reason they would be preferable under varying loads like a tractor pulling a plow through varying soil conditions. Running a tractor loader around a yard (mine was a tractor loader), moving piles of material, maintaining a torque curve isn't as important. And the diesel will generally consume less fuel than the gas. To many small hour operators, fuel consumption is not a significant cost. To high hour operators, it all comes down to the bottom line, and every penny you can squeeze out is more potential profit.

For my little PowerTrac PT425, I run the Kohler gas engine at 3600rpms constantly. It's all hydraulic and functions best that way. My IH2500b manual said specifically to run the machine at least at PTO RPMS at all times to provide adequate hydrostatic pressure, cooling, and braking.

Anyhow, you can build a strong gas engine and gear it properly to provide the same power as a diesel engine. But I think you're going to have to provide a wider range of gears or gearing to allow the gas engine to be kept within it's torque curve under load compared to a diesel engine. I have no idea of the costs associated with engine building.

TractorData.com International Harvester 25B industrial tractor information

 

[Tennsawdust]

Emission weren稚 a big problem until 5 or so years ago. A pickup isn稚 as simple as bolt in a gas motor at the end of the assembly line so I think that痴 an over inflated cost.

The emissions equipment is a big cost on road going diesels. In a Sprinter van, for instance, there is about $2500 in equipment involved after the exhaust leaves the manifold. The cost of the engines themselves are not that far apart (although the pricing usually is - the car companies figure a diesel is something people will pay more for so they charge more). Look at a Ford 2.7 Ecoboost verses Ram's Ecodiesel V6. Both are compacted graphite crank bases with die cast aluminum cylinders. Both have similar fuel injection systems. Both have two turbos with intercoolers. The crank and rods in the gas engine don't have to be quite as strong as the diesel, but do have to be strong enough to handle the pressures of the turbo. Structurally there really isn't a whole lot of difference between the two other than the crank and rods. I would think from a manufacturing cost standpoint there probably isn't $250 difference between the two, if that.

To make a gasoline engine for a tractor you would need to either make it with either more displacement or have it be turbocharged in order to get the torque you would need. A turbocharged gasoline engine can produce the same torque as a diesel. Ford's Ecoboost engines typically build full torque by 1800 rpm, which would be appropriate performance for a tractor. A larger displacement, normally aspirated engine could be more efficient however. Using the Ford analogy again, the normally aspirated 5.0 Coyote V8 returns better fuel economy while towing than the Ecoboost engines. The problem with both approaches is that a diesel is substantially more efficient under load than either style of gasoline engine.

 

[MossRoad]

The emissions equipment is a big cost on road going diesels. In a Sprinter van, for instance, there is about $2500 in equipment involved after the exhaust leaves the manifold. The cost of the engines themselves are not that far apart (although the pricing usually is - the car companies figure a diesel is something people will pay more for so they charge more). Look at a Ford 2.7 Ecoboost verses Ram's Ecodiesel V6. Both are compacted graphite crank bases with die cast aluminum cylinders. Both have similar fuel injection systems. Both have two turbos with intercoolers. The crank and rods in the gas engine don't have to be quite as strong as the diesel, but do have to be strong enough to handle the pressures of the turbo. Structurally there really isn't a whole lot of difference between the two other than the crank and rods. I would think from a manufacturing cost standpoint there probably isn't $250 difference between the two, if that.

To make a gasoline engine for a tractor you would need to either make it with either more displacement or have it be turbocharged in order to get the torque you would need. A turbocharged gasoline engine can produce the same torque as a diesel. Ford's Ecoboost engines typically build full torque by 1800 rpm, which would be appropriate performance for a tractor. A larger displacement, normally aspirated engine could be more efficient however. Using the Ford analogy again, the normally aspirated 5.0 Coyote V8 returns better fuel economy while towing than the Ecoboost engines. The problem with both approaches is that a diesel is substantially more efficient under load than either style of gasoline engine.

Again, I point out the 70s IH2500b. The gas engine is smaller in displacement than the diesel, yet makes similar power.
TractorData.com International Harvester 25B industrial tractor engine information

200 cubic inches gas VS 239 cubic inches diesel.

 

[Industrial Toys]

The technology exists to build amazing, long lasting, high quality engines. But, what manufacturer would have any interest in that?

I had a V4 Wisconsin on a stump grinder. Sixty something HP. Got rid of it, because the carburator started to get difficult. Fuel injected, that would have been a nice engine. Often used in irrigation.

 

[nards444]

The technology exists to build amazing, long lasting, high quality engines. But, what manufacturer would have any interest in that?

I had a V4 Wisconsin on a stump grinder. Sixty something HP. Got rid of it, because the carburator started to get difficult. Fuel injected, that would have been a nice engine. Often used in irrigation.

Not a good business model, lol. But there is some logic, have to figure in price. Could produce a bullet proof engine that last 50 years, but if it cost say 5k or more than the average engine would it get sold? Another thing is everything around that engine. Logically keeping a vehicle around much more than 10 years up here where there is salt just doesnt happen, and if it does its just flat out junk. So sometimes over building something that just wont get the use doesnt make sense. But then again we are also in throw away economy.

 

[4570Man]

Not a good business model, lol. But there is some logic, have to figure in price. Could produce a bullet proof engine that last 50 years, but if it cost say 5k or more than the average engine would it get sold? Another thing is everything around that engine. Logically keeping a vehicle around much more than 10 years up here where there is salt just doesnt happen, and if it does its just flat out junk. So sometimes over building something that just wont get the use doesnt make sense. But then again we are also in throw away economy.

The 6.0 in my suburban has 291,000 miles, 9300 hours and still runs perfect. I still drive it. How much more durable do you want?

 

[Industrial Toys]

Why were carbs on tractors always so simple and I'm guessing "low performance", while on cars, where it's just for fun, you had all kinds of wild, high performance, carb variations?

You look at old 2x4s, wood plank flooring, or old 18 gauge telephone wiring as opposed to some modern 26 AWG, and one is amazed at both the quality, but also the waste of materials.

 

[Agvg]

Again, I point out the 70s IH2500b. The gas engine is smaller in displacement than the diesel, yet makes similar power.
TractorData.com International Harvester 25B industrial tractor engine information

200 cubic inches gas VS 239 cubic inches diesel.

And how was the fuel efficiency on that has engine?

 

[MossRoad]

The 6.0 in my suburban has 291,000 miles, 9300 hours and still runs perfect. I still drive it. How much more durable do you want?

291,001


:laughing:

 

[Agvg]

Not a good business model, lol. But there is some logic, have to figure in price. Could produce a bullet proof engine that last 50 years, but if it cost say 5k or more than the average engine would it get sold? Another thing is everything around that engine. Logically keeping a vehicle around much more than 10 years up here where there is salt just doesnt happen, and if it does its just flat out junk. So sometimes over building something that just wont get the use doesnt make sense. But then again we are also in throw away economy.

Well, most engines today is of much higher quality than it was in the old days, it's easy to fall in to the nostalgia trapp