Ford’s “Godzilla” 7.3-liter pushrod V8 engine is a workhorse. It has played a starring role in the Ford Super Duty since 2020, and also appeared in the Ford E Series vans and the F-650 and F-750, too. But its most vital role for America’s youth? It’s the engine that’s hauling them to school!
Blue Bird Corporation is a manufacturer that deals in buses, with almost a century of history in the industry. It’s best known for building school buses that deliver students to lessons they don’t want to go to all over the country.
Blue Bird’s current triumph is that it is presently the only school bus manufacturer in the US with gas and propane-powered buses that can meet new 2027 emissions standards. That’s thanks in part to its exclusive partnership with Ford. If you want a school bus powered by Godzilla, you can only get it from Blue Bird.
In 2021, the bus manufacturer announced that its fleet would get propane and gasoline power using the mighty Godzilla V8 as a base.
The relationship between the two companies has been a long one. A Ford chassis underpinned the first Blue Bird school bus, built all the way back in 1927. “We are delighted that Ford’s powerful 7.3L engine will be at the heart of Blue Bird’s next-generation, alternative-fuel-powered school buses in North America,” said Douglas Chase, director of OEM sales at Ford Component Sales.
Propane is a really big deal for Blue Bird. The company claims that its propane-powered buses can save school districts up to $3,700 per bus per year, mostly down to lower fuel and maintenance costs. You might not have noticed school buses making the switch, but over 1,000 school districts rely on propane transportation today.
While Ford supplies the gasoline version of the Godzilla to Blue Bird, it doesn’t build a propane version in-house. Instead, Roush CleanTech is the company behind the alternative fuel version. Performance is largely comparable. Where the gas engine in the Blue Bird Vision makes 350 horsepower, the propane version from Roush makes 335 hp. Both types use the Ford 6R140 six-speed transmission.
Here are the specs on how well the propane version performs in terms of noxious emissions:
Ultimately, it makes a lot of sense for Blue Bird to partner with Ford. The 7.3-liter Godzilla is a popular engine with great specs and great parts support.
There’s one side benefit that I want you to remember, though. Imagine it’s the playoffs. Your kid’s team is all set for the big game, but the bus won’t start. If you’ve got a Godzilla under the hood of your own F-250, you might just be able to pull some parts off and save the day.
You’ll look like a goddamn hero when you do.
[Mercedes’ Note: Gas buses also make a lot of sense for school districts that don’t have huge budgets. A gas bus costs less to buy than a diesel bus and significantly less than an electric bus. Plus, while the gas engine has higher fuel costs, it has lower maintenance costs than a diesel. That’s why gas buses are still being made in an era where everything is going electric. – MS]
Story image credits: Blue Bird, Ford
Top graphic Godzilla: AmeriCantaro/stock.adobe.om
Blue Bird may offer a better powertrain option, but here in Alabama Freightliner/
Thomas still dominates the scene. I still don’t understand the fetish over these rolling junkpiles. Having dealt with school bus fleets, I would never recommend anyone to buy a Freightliner school bus.
The local sales rep is also a pompous ass. There’s another reason to stay away from Freightliners.
The 7.3 godzilla is a excellent choice for a school district the gas engine just makes more sense than diesel ,when you factor in fuel cost ,Def fluid cost ,and emissions systems replacement cost ,and engine cost itself I’d say it puts a bus well north of 100k if not 150k And not only that, but these new diesels require a lot of specialized tools and the bus garages don’t have the specialized mechanics to work on them. Buses and I Think that the gas engine makes more sense Instead of the diesel Engine
Most school districts Only get 1 or 2 buses at a time.
Another factor when selecting fuels, at least where it gets /cold/ is cold weather performance. During one of the really cold days here, where they canceled school, the superintendent sent out a rather lengthy and detailed email about all the things they take into account when making the decision to cancel school. He pointed out that one local district has diesel buses and therefore will sometimes have to cancel classes, where the gas and propane powered buses in our district would still work.
For school busses, they would be amortized over a very long period of time. Implying that maintenance and fuel costs are a substantial portion of their operating budget – these are rife for EV/Hybrid with legitimate real-life payoffs for operators.
Go, go, Godzilla
I also suspect the higher price of diesel fuel, the cost of DEF and the trouble diesel emissions systems cause have resulted in some moving away from diesel.
But really what I’d rather see is schoolbuses moving to some sort of gasoline hybrid powertrain. Schoolbuses spend a lot of time sitting around idling. A hybrid powertrain would eliminate that.
I can understand why Ford developed the 7.3L Godzilla… it replaced the 6.2L V8 and the old 6.8L V10.
But I would rather have seen Ford develop some sort of heavy duty hybrid powertrain meant for trucks. Something like a derivative of the PowerBoost hybrid used in the F150.
Ah, let’s park this monstrously agricultural diesel with a 6″ diameter tailpipe in front of a school (at head-height for the average 5yo, mind you).
Didn’t think my Friday would have me pondering the fleet economics of school buses versus transit buses, but here we are.
Heavy vehicles with low usage seem to be bad bets from an electrification/hybridization standpoint. A lot of total cost is in the capital expenditure of purchase with school buses, not the operating costs as they don’t accumulate much mileage.
So, a lower maintenance gasoline engine – even if somewhat more thirsty – probably is more suited to this role. Indeed, Ford’s whole strategy with the Godzilla V8 design seems to be built around such fleet customers: U-Haul, school buses, Super Duty trucks. Low maintenance cost and low engine cost relative to a diesel engine. Sure, the fuel economy isn’t great, but one isn’t accumulating much mileage.
Whereas transit buses tend to have much higher fuel costs as a percentage of total operating cost. They run loops around cities continuously, stopping and starting repeatedly. A diesel-hybrid (or in lower-use routes, electric) bus likely makes sense for large municipal operators.
TL;DR:
School bus = gasoline engine is likely best option
Transit bus = diesel or diesel-hybrid
Playing devil’s advocate, school buses spend a hell of a lot of time idling.
Another counterpoint
I know they’re heavy, and take a lot to get moving, but they also take a lot of energy to stop (something that buses do a lot), so regenerative braking should be factored into any discussion about a hybrid powertrain.
> Heavy vehicles with low usage seem to be bad bets from an electrification/hybridization standpoint.
One of the things that some school districts that have adopted electric buses have found is that the buses themselves can be a revenue source when sitting idle. After all, in the middle of the day (when there’s a surplus of solar energy in solar-intensive grids that can recharge them), and during evenings (when there’s a demand spike right as solar generation is falling off)/nights (where base load power sometimes has to pay customers to use power) and on weekends, they’re not being used, and therefore can participate in grid stabilization markets with the big batteries. As the rest of the vehicle is fairly cheap, all things considered, this can help the economics a lot.
To me its a sad realization that our emissions rules are so backwards that a fuel that gets basically double the economy, cant be used because the air is 10% dirtier. Sad the accepted solution is to just skip the emissions requirements of diesel and dump loads of gasoline at the problem.
I am pretty sure double the fuel burned REGARDLESS of emissions differences of gasoline to diesel mean that the air is worse off for using gas in this application.
Remember, the rules care not about efficiency, they assume a 70mpg car over 70 miles has to match the air quality of a 7mpg truck over 7 miles or its banned.
The reason bus fleets are switching to gas, just like the many other fleets doing so, is for cost, not emissions.
Also I’d be surprised if diesel got double the economy of gas.
Well argue with Mercedes herself who said exactly that in her comment below. And she owns a bus… do you?
I’d welcome a discussion.
Everything I’ve read and experienced about heavy towing and Class A RVs puts the difference at <50%, let alone 100%. If there’s a major difference between those heavy vehicles and buses, I’d be curious to know what it is and why.
Depends on the bus, the engines you’re using for comparison, and the route. A big gas V8 bus might get 6 mpg on a route while something like a DT466E might get 10 mpg. At least, that’s what mine was claimed to get when loaded. I observed 12 mpg when empty. Not exactly double, but also not insignificant. Adjust for variations like lots of stops or fewer stops.
The bigger deal is the fact that the gas bus is cheaper upfront than diesel, cheaper to maintain, and the fuel is often cheaper than diesel. A district on a tight budget may be willing to buy more gasoline than diesel because the bus itself was cheaper. Of course, at that point, an EV bus isn’t even on the menu because those are still crazy expensive without some sort of grant to help pay for them.
Edit: Keep in mind that I’m talking about buses predating this Godzilla engine. Haven’t seen many reports yet on its fuel economy, so there’s that.
It seems to be universally reported as higher than the V10 that it replaced in RV/cutaway applications, so I have no reason to doubt it would do comparatively well for a gas engine in the larger buses as well.
That shouldn’t be surprising given that the V10 was mostly engineered in the 1990s, and no one else had designed a true big block between then and the the 7.3 in 2020. In that sense, we are sometimes comparing a modern diesel with a much older gas engine.
That’s a good sign! Bringing gas fuel economy closer to parity with diesel would mean even one less reason to choose a diesel bus in the first place.
I do wonder if the diesel engine use case mostly comes down to engine longevity for vehicles that endure many many miles of hard use: tractor-trailers, transit buses, and the like.
For vehicles that accumulate less mileage or have less demanding lives, a gasoline engine seems like the lower-cost, lower-maintenance option. Doubly so in the case of the advanced emissions systems on newer diesel engines.
While some boast of old Mercedes diesel car engine longevity, my anecdotal observations is that the lifespan of a gasoline engine often exceeds the lifespan of the vehicle itself. The engine isn’t the limiting factor to lifespan usually, and an overbuilt engine in an underused application seems mostly a waste.
Yeah I’m with you on this.
I think a modern gas engine like the Ford 7.3 can stand up to hard use over a lot of miles too, and the use cases for diesel are shrinking.
I would love for a school bus mechanic to chime in, but it seems like the typical school bus mileage is well within the lifespan of a good gas engine. I’ve seen some districts toss buses at around 100,000 miles and others at around 200,000 miles or so. And those are miles built up over a decade or two. A gas engine should be able to handle that.
I have 2 cars from the same carmaker (VW), of the same generation with the same displacement (2.0L), one gas (mk7 GTI) and one diesel (mk7 TDI).
I get about 25mpg with gas and about 45mpg diesel, so not quite ‘twice’ but not far from it (also the diesel is a wagon, so longer & heavier).
And the additional cost of the diesel is, in large part, due to the required emissions equipment…
That is part of it, but diesel engines were $5-6000 options on HD trucks even before any emissions equipment was required.
Now they are $10-12K of course, but it’s not all DPF and such.
That’s a bit of an oversimplification though. In the comparison from the article there are at least 8 emissions of concern; although the EPA is really focusing on NOx, PM, NMHC and now CO2.
Burning half the fuel will roughly work out to half the CO2, but it could easily match or exceed all the other emissions. Fuel Efficient != Clean. Diesel are a prime example of this with their fuel economy being neutered to keep NOx and PM in check. Primarily the battle really seems to be NOx, but different strategies to address this have different draw backs.
For instance, EGR can be used to battle NOx, but can increase PM. SCR (Urea Injection) can reduce NOx without any downsides to the engine operation, but adds an additional fluid cost and hurts reliability thanks to the frailty of the after-treatment system. Lowering compression ratio can also reduce NOx, but hurts the Carnot efficiency of the engine.
The old saying, “there’s no free lunch” really rings true here and up until the recent Tier IV and Tier V standards the difference in allowable emissions between gas and diesel was actually quite broad. Gas engines can easily hit emission targets that diesels have been struggling to reach as of the last ten years. Pretty much across the board with exception to CO2.
That’s… not really how this works, until you get deep into heavy duty vehicles.
14,000 lbs GVWR and below, the rules are set by vehicle category, with per-mile targets regardless of how much fuel is used.
So, light duty stuff (mostly 8500 lbs GVWR and less) tends to have similar targets regardless of class (with light duty trucks allowed to have *slightly* worse bins for the criteria pollutants). A 70 MPG car, a 15 MPG pickup, and a 10 MPG passenger van classified as a “medium duty passenger vehicle” have basically the same unburned hydrocarbon, nitrogen oxide, particulate matter, and carbon monoxide standards *per mile*, not per gallon or whatever.
Then, there’s medium duty and the lightest heavy duty class – 8501 to 14,000 lbs GVWR. There, per mile targets still exist, but are higher.
And then, finally, there’s heavy duty, where emissions figures are instead per horsepower-hour, instead of per mile. This is the closest to what you’re asserting, but it’s still not directly tied to the per-gallon-of-fuel emissions you’re asserting, it’s tied to the horsepower output of the engine (because heavy duty can have very wide variance in engine output needed for a given weight to do various jobs).
Fewer sick kids and staff from diesel fumes too. My local district runs LPG buses. They have zero odor when behind them. It likely helps at the transfer points when all the students switch buses to not breathe in all those diesel fumes, plus the teachers who got hosed with bus duty.
Wouldn’t a hybrid setup work pretty well in a bus due to all that flat space on the bottom yet still having space up front for a motor to charge it?
They may have somewhat the same problem someone brought up recently about hybrid semis, which is that a hybrid large vehicle has to have huge batteries and electronics in order to recover all the energy from the regenerative braking system. If you don’t have appropriately sized parts, you lose a lot of the benefits of hybridization.
I realize buses aren’t as heavy as semis, but they’re still much larger than your average Prius so I suspect the same problem applies, even if to a lesser degree.
The biggest problems are the engineering costs of upsizing the hybrid transmission and electric motor. That huge battery isn’t cheap, either.
It’s much cheaper and easier to convert to propane, or redesign as 100% electric to serve those whose use cases match those options, and who want better product right away.
The delay with hybrids is mostly because the market is thousands of units per year, not hundreds of thousands.
Hybrid busses will be popular, it’s just taking some time to get the engineering and economics worked out.
Ok, long propane-related story here:
My uncle was fairly high up in the Royal Canadian Air Force (he personally made the case to Trudeau the Elder to buy the F18 Hornet). At one point in his career, he was stationed in North Bay.
They had a large underground garage where the base’s trucks and vehicles were maintained. The people working in this facility were getting headaches and missing a lot of work. They figured out it was because of emissions.
The staff presented my uncle with a solution: move everything over to propane. He agreed and tried to get the OK. The RCAF said no.
My uncle, however, believed that rules were just guidelines to be skirted when suitable. So, he applied to do a study on the effects of switching everything over to propane. This got approved and he was off.
What happened? Fewer sick people, no one was getting carbon monoxide-related headaches, no change to operations — a grand success.
Then the RCAF said “Hrmf…results are interesting. We’ll review them further. Shut it down.”
At which point my uncle presented the (perhaps slightly exaggerated) cost to switch everything back.
As he expected, the Air Force balked at the cost, and the propane fleet stayed.
He always smiled when he told that story. RIP.
Fond memories of living in North Bay myself and sometimes dodging bureaucracy is an art form unto itself, especially with government. I find myself smiling at his story too. Cheers!
Back when I sold parts, one of our customers was the local school district. They were slowly transitioning over to gasoline buses when the diesels were due for replacement, as the newer diesels were such nightmares for maintenance. I know emissions controls are important but DAMN are they not fussy on diesels.
My boss dreads the repair bills when we need emissions work on our semi trucks. And boy, do they need it alot.
The challenge for school buses to transition to EV’s is not operational (save for some truly rural runs) it’s financial.
These numbers are a few years old, but the math still works.
A low cost, basic diesel school bus sells for 90-100K.
An EV school bus similarly equipped is about 300K.
For most owners, the total cost of ownership of the EV bus is lower to similar with an EV.
Many school districts finances can not accommodate such large capital purchases and they are forced to stick with diesel buses if if they want to change.
If the gov’t really wants to transition school buses to EV, the lowest cost way would be to guarantee the financing of the buses with the manufacturer, not up front grants.
There is one downside that happens with the rapid transition to EV schools buses. It puts mechanics out of work faster than normal attrition due to the much lower maintenance required on them.
I’m curious about the actual fuel economy on this. My dt466e bus gets 7-9 mpg at best and is loud and on average $3.95 a gallon. That’s at best $.44 a mile. If it got 8mpg or better average, it would cost the same per mile at 3.67 a gallon.
Gas buses get more or less half the fuel economy of their diesel counterparts. Propane ranges, but I’ve seen them get a tick less than a gas bus. That’s atrocious fuel economy, but the districts math it out through cheaper acquisition and maintenance costs.
That’s something along the lines of what I had expected, but short of my $300 meth-a-bego I bought on Facebook marketplace, I’ve never dealt with big block gassers and that had no fuel gauge. Or odometer.
isn’t propane much cheaper than regular gas? In CA a gallon of propane is $2.50 – $2.80 while a gallon of Regular 87 is at least $5
Our diesel transit buses burn, on average, 3mpg. Which seems atrocious until you factor in carrying 100 people at a time. Then, all of a sudden, the diesel engine is the lowest carbon footprint per body moved. Which is why I feel mass transit vehicles (barring trains) should be the last vehicles we focus on in the carbon shift.
Given how street cars/trollies/subways started out electric over a hundred years ago and how many bus lines are already electric or hybrid it seems to me non train mass transit was long ahead of the curve.
The train I took to work today runs on biodiesel. They are studying electrifying the lines (over the next 20 or so years) but the right of way is shared with freight so they can’t use overhead power or third rail. One of the options in the study is diesel/battery hybrid locomotives. My understanding is almost all modern trains are technically hybrids due to combining a prime mover with traction motors.
I’m glad propane has gotten some traction in this segment. Of course the “all or nothing” people without the knowledge on the benefits of the relatively clean fuel will say it’s no good unless it’s got a 2-ton battery underfloor..
I’ve worked a lot of years teaching in my school district where I’ve ridden a lot of busses. Mostly you think of the excellent ride quality in those nice hard seats. It never crossed my mind that they might be powered by propane. You learn something every day.
I think some kids like school, right? Right??
IC Bus built gas and propane buses for several years with a GM derived 8.8L big block. PSI copied the big block architecture and bought a lot of engine management parts from Delphi. I am waiting for the day a YouTuber gets ahold of one of the gas versions and throws the Summit Racing catalogue at it. I bet a lot of GM big block parts, including superchargers, will work on it.
Cummins is working on a fuel agnostic engine. Basically, the short block stays the same (minus pistons) but the heads change for the fuel chosen. They hope to get into the propane, gasoline and CNG markets.
Forget a schoolbus. This engine needs to be in a sub-2,500 lb mid-engined 2-seat streamliner.
😀
Now I am all excited and no relief in sight….
Imagine it with a supercharger running 12 psi of boost with an ECU remap, making about 650 horsepower, with low stress on that giant lump of an engine. And give the car AWD to boot.
It would be a tiny thing, about as long as, but a foot lower and one and a half feet more narrow than, a Miata. Manual transmission, of course. The body would ideally be designed with a CdA value comparable to a VW XL1, so that you can get 40+ mpg cruising 70 mph on the highway, and top out at like 250 mph.
To quote Pam Poovey: “SPLOOSH!”
The best part about this comment is there is more than one possible context to interpret it.
The thing splooshing is exactly what you think it is. RIP Archer.
Nah! Its almost 200 lbs heavier than the Coyote. Don’t put that porker in anything sporty.
I thought gasoline was pretty much eliminated from school buses after that devastating crash in Kentucky that killed 27 people. Although I’m sure the gas tank is much better protected now. On that crash the end of the leaf spring on the front axle was driven through the front of the tank by the impact of the oncoming vehicle.
Gas was dead on school buses for many years after that. After 2010 emissions, the cost of diesels went up because of the DEF system, DPF and the electronics to make it work. Downtime also became an issue as early emissions systems weren’t all that reliable. That’s what kicked off the resurgence of gasoline as a school bus fuel.
The root issue isn’t gasoline, it’s the woeful crash performance of school buses – but hey, it’s easier to just change the fuel than make buses actually safe.
Another feature to these gas engines over the traditional diesel the busses around me use: No more “cold days”. As a kid we usually had 2 days a year where the busses couldn’t start because of the cold.
Sucks for the kids, but I am sure everyone else see that as a win.
Propane (LPG) systems don’t like cold either.
I had to spill lukewarm water very slowly and carefully many times on the frozen reducer to get my car started.
Maybe modern conversions have some kind of reducer pre-heating system.
I think these may be liquid propane injection systems, so minimal cold start issues.
What, they don’t just stick a pan of burning kerosene under the sump?
Sir, I live in Massachusetts, they would never do such a horrible thing like that!
A friend of mine used to place a lit charcoal BBQ (with legs removed) under his (rural) home heating propane tank when the weather got too cold for the propane to vaporize. Then he’d tent it in with insulated tarps. It looked sketchy as hell but it kept the propane flowing and the house warm.
Our kids had “cold days” in that absences were excused below -40 degrees, but class was still held and the diesel buses still ran. I actually don’t think anyone ever utilized these excused absences; it made them look like lightweights.
The buses were also equipped with Webasto diesel heaters to heat the interior (and presumably engine coolant). Never heard of one breaking down or not starting. On the east side of Alaska, the town of Tok ran an electric bus. It ran okay, but sucked a lot of energy in the winter.
I don’t think our busses had the heaters, we normally don’t run into any issues here. But every once and a while we hit -30 or so, more so with windchill, and they just can’t do it.
While I really like propane as an ICE fuel and as a refridgerant I really don’t understand having standard School busses be ICE powered in 99% of places.
The only time where it’s really necessary is when School busses are used for road trips for sports and such, and propane sure as shit won’t work for that.
I don’t know if you are campaigning for BEV buses or not, but if you are, I think the initial cost is the main inhibitor to BEV bus adoption.
Initial cost is a concern, but the cost savings from less maintenance have to offset it quite a bit. L2 charging is most likely plenty for the busses and L2 charging is cheap.
There must be a lot of cost savings to recoup ~$200,000 difference in initial cost. I just did a quick search, and it seems that a traditional diesel bus costs about $100,000, and an EV bus costs $300,000+. I know from previous work experience that many school bus companies don’t keep their big buses for longer than five years, meaning they would need to save over $40,000 per bus annually. My numbers may be wrong, but if it made financial sense, we would see profit-driven companies choose the EV route. Also, while yes L2 charging is cheap, it still costs something versus an empty parking lot and using the gas station down the road. I agree EV buses would be cool, I’m just saying there’s a reason I’ve never seen one.
Because electric busses are 3x more expensive than ICE busses, and that’s just for the bus, not the related infrastructure (the school bus depot near me is just a gravel lot surrounded by a chain link fence, with a 3 bay pole barn and a construction office trailer, I question if they even have enough electric service coming from the street to support more than a couple of chargers, at most)
And most states also set a hard age limit on school busses – in mine, its 10 years, so that triple cost expense would be repeated every decade, even though the bus itself would likely still be in perfectly fine condition (as the ICE buses usually are at retirement, but at least they’re comparatively cheap)
The busses can probably get by with L2 charging which isn’t expensive or that demanding for the grid.
“There’s one side benefit that I want you to remember, though. Imagine it’s the playoffs. Your kid’s team is all set for the big game, but the bus won’t start. If you’ve got a Godzilla under the hood of your own F-250, you might just be able to pull some parts off and save the day.”
Or the bus can save the day for you. You think those kids will complain if they miss school because you swiped some parts from their bus to fix your truck? Hell, you’ll be a bigger hero to them than Spiderman.
https://www.youtube.com/watch?v=4RKZ_6x-KRU
This vid of someone going 0 – 90 with that engine alone makes me want something with one. Alas, it’s unlikely.
Maybe Blue Bird is a big name in buses, but where I grew up was a Thomas Built Buses area.
If propane is akin to LNG, one major benefit from running it is how absolutely spotless the inside of the engines remains.
Propane is dirtier than LNG, but still burns very cleanly compared to regular gas. It’s also hard on the valve seats, but these days there are aftermarket valve lubrication systems available.
I used to drive an old propane powered fork lift and that thing belched the stinkiest black smoke. Kind of soured my opinion of that fuel.
Sounds to me as if there was something seriously wrong with the engine of that forklift, probably bad piston rings allowing it to burn oil or something along those lines. All the LPG forklifts I’ve been around don’t smoke at all.