Buying Advice Does anyone make real Gas tractors anymore?

[sbct]

Gas engines just don't make the torque of diesel engines and torque is exactly what most people need in tractor applications. Oversimplified but a strong running gas engine will make similar hp and tq numbers while a strong running diesel can make double the torque as it's hp rating.

 

[Roger66]

Gas engines just don't make the torque of diesel engines and torque is exactly what most people need in tractor applications. Oversimplified but a strong running gas engine will make similar hp and tq numbers while a strong running diesel can make double the torque as it's hp rating.

I think the torque argument is nonsense. I used to drag race a '73 Camaro, Towed to the race track of course. I listened for years to the other drivers BS about the superiority of their diesel trucks over my gasser. One day we dropped the trailers and ran the trucks out on the track, I beat most, some beat me slightly. Then they all said well drag racing is not a fair comparison, blah blah blah, Towing, Torque, blah, blah. My truck was an old 82 F250 that i stuffed a mildly built 460 into. Not a expensive race engine, just a mild build with towing as the goal. Years ago when I gave up on the war on rust, I replaced it with a 2003 F350 with a 7.3L turbo diesel. I love it, but it has no more towing power than my old 460 did. The diesel clearly wins on fuel economy, but you more than pay for the fuel with the engine upcharge. Also the repairs on a diesel can be Huge. I blew a turbo down south towing a big camper tp Bristol and the cost to replace the turbo was more that it cost me to buy an build my old 460. Some day when the injectors or injector pump will need service it will easily cost more than a couple of 460's even if the base engine lasts significantly longer, the overall cost will be more than if I burned out a couple of 460's. If your a pro out on the fields all day every day, you will certianly prefer Diesel, but for most COMPACT tractor owners are not real farmers and i bet a Gasser would be overall superior. I think the emissions controls for gassers are more mature and reliable and cheaper. I think the DOC systems are superior to the DPF systems, but they are still electronic fired common rail engines. Perhaps the common rail design will prove to be awesome, but for me the jury is still out. Diesel is very nice, but it's not magic power to weight is power to weight regardless of the exhaust fumes your sniffing. The Diesel is just does it while spinning slower.

 

[Oldpath05]

("I think the torque argument is nonsense.")<<<That's right, Bla Bla Bla................hp is hp and the transmission makes the torque, todays modern gas motors are better than diesel, but my youngest son says just the opposite, isn't fun disagreeing and arguing with people you'll never see or know........

 

[jmc]

Good thread. I like the idea of an electric tractor for my use. It might be the only electric vehicle where the battery weight is an asset rather than a liability. And separate motors on the front wheels instead of a driveshaft...

 

[DavesTractor]

There was another thread about gas vs diesel, and questioning why no new tractors have gas engines. It was a lengthy thread, with a couple guys beating up each other about torque vs hp and so forth. If anyone hasn't seen that thread, it might be worth the search.

Seems it is easier to make torque with a diesel and at a lower RPM. However if the transmission and pto speeds and such were designed for a higher input speed from the engine, I'd think you could just spin the gas engine a little higher for full pto power. Maybe instead of 2400 rpm, make it 3200 rpm. And if you look at the SCUT diesels today, many are already rated at 3200 rpm if their engines are on the smaller displacement end of the spectrum for the size of tractor.

One concern with a modern gas engine as you go up in HP is that it would probably require a catalytic converter, 02 sensors, computer controls and so forth. That will drive up costs and complexity. If costs and complexity are nearly at diesel levels, then we might as well have our beloved diesels.

In the industrial world, I am seeing a lot of gas engine options now that we did not see 10 years ago. We might be seeing a trend.

 

[ericm979]

Yes, a gas engine can make the same power as a diesel if it's spun a little faster. Diesels make more torque because of the higher compression ratio (and to a smaller extent from the higher BTU content of the fuel). But they're limited to low rpm because the parts are heavier to withstand that high compression ratio, and until modern electronic ones came out, the fuel injectors could not keep up.

But it's hp that moves the tractor. Just change the gearing and a gas engine could do as well. It'd be a low revving engine compared to cars and trucks- no need to rev to 6k rpms. 3600 (like generator engines) is probably enough. Pushrods and two valves per cylinder would suffice. (after all look at the power and flexibility that GM can get from pushrods and two valves per cylinder).

They'll need emissions equipment but that's a known quantity since the automotive world has been doing it for years and the requirements for tractors aren't as strict. Catcons are cheaper than DPFs and the FI is commodity. Probably doesn't need direct injection to meet emissions.

It sure seems like it would make sense.... except the market is conditioned to think that "real" tractors have diesels. The BOM cost savings is probably under $2k, plus a big hit for the re-design. The first company to market with a gas tractor would have to discount that much or more to move product. It'd be a huge bet that'd only pay off if the market accepts the gas tractor so well that they can charge the same price as diesel.

 

[DavesTractor]

Great input Eric. What you mentioned about 2 valve GM engines and pushrods is so true. LS engines with factory HP ratings over 500 HP, and pretty easily modded with a keyboard and maybe a cam change to well over 600, and then on towards 1000HP with forced induction. And it uses pushrods and 2 valves! So I think you are right, we would not need an expensive engine, no need for overhead cam, direct injection and so forth. Many modern engines put out somewhere near 100 hp per liter and are reliable. If we put a 2 liter gas engine in a tractor and asked for 40 hp, there would be a lot of margin built in for duty cycle.

 

[lescarpentier]

There was another thread about gas vs diesel, and questioning why no new tractors have gas engines. It was a lengthy thread, with a couple guys beating up each other about torque vs hp and so forth. If anyone hasn't seen that thread, it might be worth the search.

Seems it is easier to make torque with a diesel and at a lower RPM. However if the transmission and pto speeds and such were designed for a higher input speed from the engine, I'd think you could just spin the gas engine a little higher for full pto power. Maybe instead of 2400 rpm, make it 3200 rpm. And if you look at the SCUT diesels today, many are already rated at 3200 rpm if their engines are on the smaller displacement end of the spectrum for the size of tractor.

One concern with a modern gas engine as you go up in HP is that it would probably require a catalytic converter, 02 sensors, computer controls and so forth. That will drive up costs and complexity. If costs and complexity are nearly at diesel levels, then we might as well have our beloved diesels.

In the industrial world, I am seeing a lot of gas engine options now that we did not see 10 years ago. We might be seeing a trend.

These are the specs of the Ford 2600 tractor engine,diesel and gas.Judging by the identical size it appears to be the same block used on both.The gas engine compares favorably to the diesel and appears to develop full torque at a lower RPM.With the DPF and all of the associated problems I wouldn't hesitate to buy a gas tractor.It is easier to meet the current emission requirements with gas engines.I own a B3350 so my bias and frustration is quite understandable.

 

[LD1]

Dont know all the EPA regulations so perhaps that is a holdup. Not to mention the dreaded issues with ethanol.

But the whole torque vs HP is always comical.

You can build either to do exactly what you want.

Size the engine based on the HP that you require. Because HP determines how fast you are gonna complete your work.

Torque at the engine is irrelevant. It can be changed with gearing. Need more torque....add a lower gear. Get by with less torque, add a higher gear.

A 50HP gasoline engine rated for continuous duty is fully capable of doing the exact same work in the exact same amount of time as a 50hp diesel also rated continuous duty. There are advantages and disadvantages to both.....but torque certainly is NOT one of them.

 

[Btown]

These are the specs of the Ford 2600 tractor engine,diesel and gas.Judging by the identical size it appears to be the same block used on both.The gas engine compares favorably to the diesel and appears to develop full torque at a lower RPM.With the DPF and all of the associated problems I wouldn't hesitate to buy a gas tractor.It is easier to meet the current emission requirements with gas engines.I own a B3350 so my bias and frustration is quite understandable.View attachment 524489

The only problem is that new gas engines in cars are coming with GPF (gasoline particulate filters) on them since they are getting to dirty for EPA regulations.