Cummins 6.7 Gas

[Captainp4]

28 minutes ago, silvrsvt said:

The problem is that you have all that extra weight in the engine block that isn't necessary for gas engine due to the lower compression ratios. I'd also venture to guess that the setup for the heads for a Diesel and Gas engine could be quite different also, depending on what they use. 

Weight would certainly be a drawback, but I imagine it's not of much consequence in the class truck they're building them for. Few hundred extra pounds is a drop in the bucket paid off with higher dependability and longevity. I think it's more about making these things survive in this weight class, all that extra weight aids in cooling and rigidity under heavy load.
Diesel heads are usually pretty limited air flow wise at higher rpm (where gas engines usually live), but looks like they are mimicking the same or very close rpm range between gas and diesel with this one. All conjecture on my part, but it is an interesting engine.

[7Mary3]

51 minutes ago, GearheadGrrrl said:

IIRC Cummins tried the same thing a half century ago when they converted their small diesel V8 to a "Giesel". Didn't hear any complaints about them, but that might be because they didn't sell many!

 

Oh yeah!  That was done at the request of White Motors.  When White spun off Diamond Reo in 1972 the Reo gas engines were included, that left White without a gasoline option.  For a year or two White offered the GMC V-6's in some 4000 series trucks until they introduced the 'Giesel'.  The 'Giesel' or 'Mustang VIII' as it was sometimes called was basically a Cummins 470 V-8 re-engineered into a gasoline engine.  Lower compression pistons, spark plugs where the injectors were, a distributor and a 2bbl. Holley carburetor.  I know few were made, but I never heard anything bad about the Giesel either.  It was bound to be better than any of the small Cummins V-6 and V-8 diesels!

[jpd80]

The ball ripping thing here is that OPEC is desperately trying to raise the price of crude to $100/barrel

and the US needs to fight this hammer and tong as it’s just the oil nations trying to bleed us all again.

 

If that Price jumped to $100/ barrel, I think diesel becomes more in play but it needs advanced modern

emission technology to drop emissions to super low levels. Bosch found the key after dieselgate but 

it wasn’t able to be retrofitted to existing diesels. It basically uses all existing emissions equipment but

requires diesels to be run hotter and more importantly, the temperature controlled in a lot narrower range.

 

https://www.bosch.com/stories/new-diesel-engine-technology/

 

 

 

Wondering if smaller diesel Gen set and battery setup would work better in semi trucks but that’s another topic..

Edited April 9 by jpd80

[silvrsvt]

5 hours ago, jpd80 said:

The ball ripping thing here is that OPEC is desperately trying to raise the price of crude to $100/barrel

and the US needs to fight this hammer and tong as it’s just the oil nations trying to bleed us all again

 

the US is more or less energy independent from the rest of the world at this point.

 

 

[Flying68]

12 hours ago, silvrsvt said:

 

CVT don't work for towing applications like this engine would be required to be doing...that is my response to that. It might work in a light duty application, but it won't for vehicle that needs to tow or haul things. 

What does a CVT have to do with hybrid applications in large vehicles (trucks)?  The F-150 hybrid is most definitely not a CVT, and I wouldn't expect a CVT in any other large truck application.  I would expect a similar setup to the F-150 hybrid with an EM inline between the ICE and the transmission.

[Flying68]

N/M

Edited April 9 by Flying68
double post

[Rick73]

11 hours ago, Captainp4 said:

Weight would certainly be a drawback, but I imagine it's not of much consequence in the class truck they're building them for. Few hundred extra pounds is a drop in the bucket paid off with higher dependability and longevity. I think it's more about making these things survive in this weight class, all that extra weight aids in cooling and rigidity under heavy load.
Diesel heads are usually pretty limited air flow wise at higher rpm (where gas engines usually live), but looks like they are mimicking the same or very close rpm range between gas and diesel with this one. All conjecture on my part, but it is an interesting engine.

There can be quite a bit of weight difference when comparing similar power levels.  The diesel Cummins 6.7L is just under 1,000 pounds, which makes it very close to Ford Power Stroke.  By comparison, the gasoline 7.3L Ford V8 is “about” 400 pounds lighter.  Adding emissions equipment and other mass to mitigate diesel differences makes a similar diesel pickup up to 700 ponds heavier.  Granted, diesel has higher GCWR even when gasoline has equal power rating, suggesting diesel engines are designed to work at higher percentage of rated power for long periods.

 

Regarding engine speed, part of reason large diesel engines run much slower than gasoline is that they often have much longer stroke.  When comparing engines, piston speed can often be more useful than RPM.  The Cummins has a 124 mm stroke (4.88 inches) which is considerably longer than Ford 7.3L gasoline at 101 mm (3.98 inches).  Basically, the Cummins at 3,200 RPM (max shown on chart) is equivalent in piston speed to Ford 7.3L gasoline at 3,900 RPM, which happens to be where commercial power rating was limited.  Obviously piston speed is just one limitation in that diesel fuel injection, relative to gasoline engines, can also limit RPM, particularly in smaller engines.  Anyway, it’s not unusual for diesels to have a lot more torque than power compared to gasoline engines.

[silvrsvt]

2 hours ago, Flying68 said:

What does a CVT have to do with hybrid applications in large vehicles (trucks)?  The F-150 hybrid is most definitely not a CVT, and I wouldn't expect a CVT in any other large truck application.  I would expect a similar setup to the F-150 hybrid with an EM inline between the ICE and the transmission.

 

They don't-I was taking issue with adding a hybrid to large truck would automatically make it so much more efficient when things like the F-150 powerboost show it really doesn't make a huge impact like it does in other products that are smaller/lighter and use a CVT. 

 

Its the application of scale-larger vehicles are going to need a bigger motor and larger batteries, which in turn add more weight, which impacts performance and FE, amoung other things.

 

I also think if it made that big of an improvement. manufactures in the HD market would be rolling it out sooner then later. 

Edited April 9 by silvrsvt

[Flying68]

2 minutes ago, silvrsvt said:

 

They don't-I was taking issue with adding a hybrid to large truck would automatically make it so much more efficient when things like the F-150 powerboost show it really doesn't make a huge impact like it does in other products that are smaller/lighter and use a CVT. 

 

Its the application of scale-larger vehicles are going to need a bigger motor and larger batteries, which in turn add more weight, which impacts performance and FE, amoung other things.

 

I also think if it made that big of an improvement. manufactures in the HD market would be rolling it out sooner then later. 

I don't think gross efficiency is the goal.  The goal is to increase usable power and torque without increasing emissions.  Diesel emissions are the big target and currently technology and scrubbing is pretty well maxed out.  The logical next step would be hybridization where your diesel engine can be set to run at its min emissions level and you make up the peak torque with a hybrid setup.  The other option that may be promising and might make its way into heavy trucking would be diesel-electric systems where you use high torque EM's as your only direct drive (much like a train) and you utilize a much small diesel generator and battery pack (to act as a buffer and capture regen energy).  The diesel could then be sized to deliver only the power required during constant load highway power resulting in much more efficient operation (constant power).  A diesel-electric train doesn't use a battery, instead driving the electric motors directly from the diesel engine, however the torque control is much more precise with the electric drive and you eliminate failure points on the drive train.

A series hybrid gas truck could also replace a diesel setup, providing much better emissions with similar power and torque, while having much lower emissions and maintenance costs.

[Rick73]

41 minutes ago, Flying68 said:

A series hybrid gas truck could also replace a diesel setup, providing much better emissions with similar power and torque, while having much lower emissions and maintenance costs.

Agree that’s direction heavy trucks may be headed, though for over the road applications, I think a modified series hybrid system may be used where a clutch will connect diesel engine directly to drive wheels once truck reaches cruising speed.  That greatly reduces generator and electric-motor losses.  A similar approach is being used in some hybrid automobiles which further increases highway fuel effficiency.

[SoonerLS]

4 hours ago, silvrsvt said:

 

the US is more or less energy independent from the rest of the world at this point.

 

 

Although we're not technically energy independent, we are a net exporter, at least as of the last numbers published.

[Bob Rosadini]

23 hours ago, 7Mary3 said:

 

Oh yeah!  That was done at the request of White Motors.  When White spun off Diamond Reo in 1972 the Reo gas engines were included, that left White without a gasoline option.  For a year or two White offered the GMC V-6's in some 4000 series trucks until they introduced the 'Giesel'.  The 'Giesel' or 'Mustang VIII' as it was sometimes called was basically a Cummins 470 V-8 re-engineered into a gasoline engine.  Lower compression pistons, spark plugs where the injectors were, a distributor and a 2bbl. Holley carburetor.  I know few were made, but I never heard anything bad about the Giesel either.  It was bound to be better than any of the small Cummins V-6 and V-8 diesels!

Wow-forgot about that one!

[jpd80]

18 hours ago, silvrsvt said:

 

the US is more or less energy independent from the rest of the world at this point.

North American crude is mostly the light sweet, low sulphur type which is also very easy to refine.
The unfortunate part is that most  of the refineries are set up to process the heavier less sweet crude

oil that’s normally imported from the Middle East.
 

We all hope for true oil independence but I fear it’s still a ways off…..

Edited April 10 by jpd80

[GearheadGrrrl]

And even though we have the capability to produce our own oil, the world market sets the prices...

[Rick73]

On subject of energy independence, we presently have a good supply of natural gas, and Cummins is making engines available for various single fuels.  The B6.7 will run on diesel, natural gas, gasoline, and propane.  It would seem the large X15N natural gas engine could compete with battery-electric semi on long haul applications, and or reduce dependence on oil.

 

Below is from new X10 engine line that will replace the L9 and X12 engines, intended for medium and heavy duty trucks.
 

ABOUT THE FUEL AGNOSTIC PLATFORM 

The engine is built on Cummins’ fuel agnostic platform. These new fuel-agnostic engine platforms feature a series of engine versions that are derived from a common base engine, which means they have some parts commonality. Below the head gasket of each engine will largely have similar components and above the head gasket will have different components for different fuel types. Each engine version will operate using a different, single fuel. 

Cummins is offering a full portfolio of products in 2026 to cover the medium-duty and heavy-duty customer needs, including the new 15-liter natural gas engine, the X15N. Additionally, the B6.7 will be offered in diesel, natural gas, gasoline and propane. 
 

 

[7Mary3]

Interesting topic, but it is ironic that Ford will probably be the LEAST likely truck manufacturer to offer the B6.7 Gas.  The engine is attracting considerable interest, particularly from the manufacturers currently offering the B6.7 Diesel.  Freightliner has already confirmed to their dealers, International is likely, Isuzu/Chevy a strong possibility in their class 6/7 LCF, and Mack would be silly not to in their medium duty.  Good thing for Ford is they should still maintain a substantial price advantage over those potential gasoline medium truck competitors.  

[Bob Rosadini]

On 4/13/2024 at 12:00 PM, 7Mary3 said:

Interesting topic, but it is ironic that Ford will probably be the LEAST likely truck manufacturer to offer the B6.7 Gas.  The engine is attracting considerable interest, particularly from the manufacturers currently offering the B6.7 Diesel.  Freightliner has already confirmed to their dealers, International is likely, Isuzu/Chevy a strong possibility in their class 6/7 LCF, and Mack would be silly not to in their medium duty.  Good thing for Ford is they should still maintain a substantial price advantage over those potential gasoline medium truck competitors.  

Commercial truck guy at local dealer just told me if you want a 650/750 PS you are looking at a year wait.  Apparently profitability/demand for 250-350, and probably 450,550 leave OAP with low allocation.  You would think this would now make air brakes on a gas 650/750 a top priority but probably not in their infinite wisdom.

 

On another note, one of biggest mulch suppliers in Mass/RI has about 10 satelite locations that are fed from main facility that processes the logs.  These locations have a 750 with bodies that are probably capable of 15 yds.  I went by the main facility the other day and looked like they had a bunch of new trucks in.  A couple of days later I stopped at one of the satelites and one of these new trucks was there.  Big heavy rubber, aluminum wheels and no V-8 or PS badge.  so I went around to  other side and there was the DEF tank.  No reason PS badge would not have been on this truck as it would not have interferred with wrap/decals.  Could these be running some test engine??

[7Mary3]

1 hour ago, Bob Rosadini said:

Commercial truck guy at local dealer just told me if you want a 650/750 PS you are looking at a year wait.  Apparently profitability/demand for 250-350, and probably 450,550 leave OAP with low allocation.  You would think this would now make air brakes on a gas 650/750 a top priority but probably not in their infinite wisdom.

 

On another note, one of biggest mulch suppliers in Mass/RI has about 10 satelite locations that are fed from main facility that processes the logs.  These locations have a 750 with bodies that are probably capable of 15 yds.  I went by the main facility the other day and looked like they had a bunch of new trucks in.  A couple of days later I stopped at one of the satelites and one of these new trucks was there.  Big heavy rubber, aluminum wheels and no V-8 or PS badge.  so I went around to  other side and there was the DEF tank.  No reason PS badge would not have been on this truck as it would not have interferred with wrap/decals.  Could these be running some test engine??

 

Does it have anything to do with emissions?  The 6.7L Powerstroke appears to be non-compliant for 2025 CARB.  Since Ford has already started the 2025MY for the 650 and 750, the trucks are gas only now here in California.  Diesels are not available in 2025 650's and 750's.  Isn't Mass. a CARB state?

[Bob Rosadini]

5 hours ago, 7Mary3 said:

 

Does it have anything to do with emissions?  The 6.7L Powerstroke appears to be non-compliant for 2025 CARB.  Since Ford has already started the 2025MY for the 650 and 750, the trucks are gas only now here in California.  Diesels are not available in 2025 650's and 750's.  Isn't Mass. a CARB state?

I am aware that like sheep, this state is following Calif.  But does a state have to  follow all provisions?  Plus wouldn't a dealer know that it is not a matter of availability and a wait of a year but rather  it is well known that a PS will not be available in CA and Oregon in 25, wouldn't that be common knowledge here?

 

Again my biggest question is why the continued BS given as reasons for unavailability of air brakes??

The  utilities around here  all run heavy single axles-be they dump trucks towing a tandem tag axle usually carrying  a Deere or Cat loader/backhoe or a heavy bucket/polecat towing a big cable reel- I would assume those have cable trailers have air brakes?  I would assume 7M you have similar needs??

[twintornados]

On 4/10/2024 at 3:19 AM, jpd80 said:

North American crude is mostly the light sweet, low sulphur type which is also very easy to refine.
The unfortunate part is that most  of the refineries are set up to process the heavier less sweet crude

oil that’s normally imported from the Middle East.
 

We all hope for true oil independence but I fear it’s still a ways off…..

 

Don't forget Venezuela....their crude needs more refining due to it's higher sulfur content.

[silvrsvt]

5 hours ago, twintornados said:

 

Don't forget Venezuela....their crude needs more refining due to it's higher sulfur content.

 

I was under the impression that they have serious issues with their energy producing market because they don't have anyone to take care of it and its output is shrinking. 

[7Mary3]

16 hours ago, Bob Rosadini said:

I am aware that like sheep, this state is following Calif.  But does a state have to  follow all provisions?  Plus wouldn't a dealer know that it is not a matter of availability and a wait of a year but rather  it is well known that a PS will not be available in CA and Oregon in 25, wouldn't that be common knowledge here?

 

Again my biggest question is why the continued BS given as reasons for unavailability of air brakes??

The  utilities around here  all run heavy single axles-be they dump trucks towing a tandem tag axle usually carrying  a Deere or Cat loader/backhoe or a heavy bucket/polecat towing a big cable reel- I would assume those have cable trailers have air brakes?  I would assume 7M you have similar needs??

 

As for the gas 650/750 air brakes, my hunch FWIW is that it ended up requiring some expensive engineering and Ford doesn't see enough demand to justify it.

 

We use a lot of large single-axle dumps, but they are 33,000 GVW with a Cummins L9N and Allison 3000 series transmission.  Don't even look at Fords for that application, GCW is too light.  

[twintornados]

2 hours ago, silvrsvt said:

 

I was under the impression that they have serious issues with their energy producing market because they don't have anyone to take care of it and its output is shrinking. 

 

Don't know of that, but Venezuela's state oil company owns CITGO