Cummins 6.7 gas motor

[WildBill138]

They have HLAs just like pushrod V8s, they're just smaller and in a different location.

But what do lifters have to do with anything?

Well new ram and chevy are having major lifter issues, for one. A dohc engine like the coyote or 1uz would solve that. HLA lash adjustment seems to me more robust. Though l do prefer shims.

 

[flan]

Well new ram and chevy are having major lifter issues, for one. A dohc engine like the coyote or 1uz would solve that. HLA lash adjustment seems to me more robust. Though l do prefer shims.

I follow the ford 7.3s and they do as well.

 

[thecastle]

I for one am interested in seeing what Cummins releases. I run Hemis because they're gas. I no longer have needs driving the extra outlay for the Cummins diesel, or the extra maintenance cost, driving more to meet the diesel's minimum needs, or the government DEF requirement. A gas Cummins with competitive specs and pricing sounds pretty intriguing. I don't have a problem with turbos if implemented well. I've run a fair amount of turbo equipment over the years, cars, trucks (diesel), tractors both gas and diesel, and more. It's hard to imagine Cummins producing something that wouldn't be useful.

I remember pulling big loads with old Chevy 2500s with both 6-cyl and 8-cyl engines back in the day. They were solid workhorses. I remember the heated discussions at a local bar, old-school social media, when Chevy released the 396 for its trucks. Discussions about who needs all that 310hp and 410lbft of torque? How much extra you want to pay when your truck already meets your needs? How reliable is that thing going to be? Isn't it just going to overheat in that engine bay? You going to be able to fix it yourself? Times really haven't changed as much as some think.

BTW, this attached PDF is from the Cummins site. Some impressive torque curves. And there's a bit of Cummins discussion on this page: https://www.cummins.com/engines/octane

Agreed, a gasoline turbo-charged engine can be just great if done right and very reliable. However, the current trend of turbo-charged downsized engines that are compliance engines designed to meet the NHTSA CAFE standards hasn't been a good match for large vehicles. In the real world they often don't deliver an improvement in fuel economy and the car makers I suspect to keep costs low don't build a lot of durable gasoline-turbo engines. Look at how often ford turbo gas engines fail. Though my twin-turbo gas v8 has been flawless in over 100K miles.

Me I think that RAM has a real market opportunity with the 6.7 gas-turbo motor. There has always been a big performance gap between the base v8's and the turbo dieseles that leaves plenty of room for a turbo gas engine. With gasoline engines being fundamentally cheaper to produce due to easier emissions compliance and no need to achieve very high torque ratings at very low rpm's as they can rev. The only thing that really keeps me from gas, is fuel tank capacity. With a diesel its very easy to add a bigger fuel tank, or an in-bed tank. Gasoline not so much and I like having big range for when I'm towing out in the middle of nowhere. But given that its what 12,000K to upgrade to a 6.7 diesel HO from a 6.4, that is a ton of money.

 

[justpassinthru]

Agreed, a gasoline turbo-charged engine can be just great if done right and very reliable. However, the current trend of turbo-charged downsized engines that are compliance engines designed to meet the NHTSA CAFE standards hasn't been a good match for large vehicles. In the real world they often don't deliver an improvement in fuel economy and the car makers I suspect to keep costs low don't build a lot of durable gasoline-turbo engines. Look at how often ford turbo gas engines fail. Though my twin-turbo gas v8 has been flawless in over 100K miles.

Me I think that RAM has a real market opportunity with the 6.7 gas-turbo motor. There has always been a big performance gap between the base v8's and the turbo dieseles that leaves plenty of room for a turbo gas engine. With gasoline engines being fundamentally cheaper to produce due to easier emissions compliance and no need to achieve very high torque ratings at very low rpm's as they can rev. The only thing that really keeps me from gas, is fuel tank capacity. With a diesel its very easy to add a bigger fuel tank, or an in-bed tank. Gasoline not so much and I like having big range for when I'm towing out in the middle of nowhere. But given that its what 12,000K to upgrade to a 6.7 diesel HO from a 6.4, that is a ton of money.

While I agree somewhat about the fuel economy constraints, I think the ability to generate 400lb-ft of torque at 700 RPM, and 600+lb-ft at 1500 RPM is a potential major selling point to folks that want it. They'll probably allow a bit of fuel economy loss. I'm less sure about your discussion of diesel vs gas tank size. I suspect that with the right motivations, Ram could find a way to get a larger tank into the HDs to extend the range a bit.
It's all about if and how they implement.

 

[Riccochet]

My problem with this 6.7 gas engine is:

1) weight. It weighs as much as the diesel engine, that's going to chew in to payload.
2) Horsepower. The high output version is only rated for 325 HP, with the standard at 250 HP. After driveline loss you'd be lucky to see 230-240 to the wheels, and like 180 for the standard output

The weight, plus lower HP is going to make this thing a slow dog.

I'll trade some of that 660 ft/lbs of torque for more horsepower. Balance it out. Give me 450'ish HP and 500 ft/lbs.

 

[WildBill138]

Ya those numbers would be pretty awful. It needs to be better than the 6.4 at 420/480. My 3.0 turbo makes 500 easily, a 6.7 should make 800 hp.

 

[56ram2500]

My problem with this 6.7 gas engine is:

1) weight. It weighs as much as the diesel engine, that's going to chew in to payload.
2) Horsepower. The high output version is only rated for 325 HP, with the standard at 250 HP. After driveline loss you'd be lucky to see 230-240 to the wheels, and like 180 for the standard output

The weight, plus lower HP is going to make this thing a slow dog.

I'll trade some of that 660 ft/lbs of torque for more horsepower. Balance it out. Give me 450'ish HP and 500 ft/lbs.

Why are so many hung up on HP being 325 HP is more than the HP out put of a 350 Cummins that was in a semi I drove back in 1985, many times I drove that thing hauling just under 101K gross weight around WA, OR, ID, NV & UT

 

[flan]

Why are so many hung up on HP being 325 HP is more than the HP out put of a 350 Cummins that was in a semi I drove back in 1985, many times I drove that thing hauling just under 101K gross weight around WA, OR, ID, NV & UT

What was the torque, number of transmission speeds, displacement and gearing on the 350hp Cummins motor? There’s more to a vehicles capabilities than HP.

 

[56ram2500]

What was the torque, number of transmission speeds, displacement and gearing on the 350hp Cummins motor? There’s more to a vehicles capabilities than HP.

It was only 300 HP, no idea of TQ number, trans was a 13 speed road ranger with gears 4.33, IIRC it had around 1200 tq at 2100 rpms about the same as the big cam 2 400..

 

[jsalbre]

You can drag a building with a hand crank if the gearing is low enough.

I’m sure that old truck moved that weight just fine, but I also bet it took 5 miles to get up to 60mph.

 

[HarryN]

I wonder if the HP rating is limited by the goal of using low octane rated fuel ?

For almost 45 years, BMW has had variable cam engines that can gain performance and range from higher octane fuel but still also run lower octane fuel for those too cheap to buy decent gasoline. There is a gas station not that far away that sells fuel all the way up to ~ 97 - 98 octane, and for run we tested 95. Definitely gained in mpg, don't have a real way to test performance. 91 is common here and that is what we normally use.

I am "assuming" that the octane engine does not have variable cam capability, but is there another way to accomplish a similar thing - still able to run on cheap / low octane gas, but still able to gain performance from running higher octane fuel ?

 

[H3LZSN1P3R]

I wonder if the HP rating is limited by the goal of using low octane rated fuel ?

For almost 45 years, BMW has had variable cam engines that can gain performance and range from higher octane fuel but still also run lower octane fuel for those too cheap to buy decent gasoline. There is a gas station not that far away that sells fuel all the way up to ~ 97 - 98 octane, and for run we tested 95. Definitely gained in mpg, don't have a real way to test performance. 91 is common here and that is what we normally use.

I am "assuming" that the octane engine does not have variable cam capability, but is there another way to accomplish a similar thing - still able to run on cheap / low octane gas, but still able to gain performance from running higher octane fuel ?

87 is decent gas and the cost difference will never net you MPG to make up the cost difference between 87 and 91. Here the difference between 87 and 91 is 1.139/gallon so a full tank at say 30gal is 34$ more you would need to gain a ton of MPG to be worth the extra cost going from 4.77/gal for 87 to 5.91/gal for 91. Thankfully diesel is down to 4.65/gal now

 

[HarryN]

87 is decent gas and the cost difference will never net you MPG to make up the cost difference between 87 and 91. Here the difference between 87 and 91 is 1.139/gallon so a full tank at say 30gal is 34$ more you would need to gain a ton of MPG to be worth the extra cost going from 4.77/gal for 87 to 5.91/gal for 91. Thankfully diesel is down to 4.65/gal now

Here, the difference between the low end gas and premium is < 50 cents per gallon,often less. Sometimes range is more important than mpg - it is in my mind, that is the primary reason I am spending so much time learning about diesel. Locally, diesel varies from being ~ the same price as premium fuel to 20 -30 cents more, mostly due to government manipulation.

Diesel would easier outside of California, but reality is that this is where I am.

We are talking about $100K truck, and paying big bucks for a premium engine, to me that means using a premium fuel, premium oil, etc. This is not a $5K clunker mobile that you just ignore and pour in some oil if it leaks out too much.

Perhaps they can manipulate it with the amount of boost pressure, that would help in the mountains where no boosted engines really suffer.

I guess we will see what happens - if the Octane engine really hits the RAM 2500 / 3500 platform in the next year or not.

 

[H3LZSN1P3R]

Here, the difference between the low end gas and premium is < 50 cents per gallon,often less. Sometimes range is more important than mpg - it is in my mind, that is the primary reason I am spending so much time learning about diesel. Locally, diesel varies from being ~ the same price as premium fuel to 20 -30 cents more, mostly due to government manipulation.

Diesel would easier outside of California, but reality is that this is where I am.

We are talking about $100K truck, and paying big bucks for a premium engine, to me that means using a premium fuel, premium oil, etc. This is not a $5K clunker mobile that you just ignore and pour in some oil if it leaks out too much.

Perhaps they can manipulate it with the amount of boost pressure, that would help in the mountains where no boosted engines really suffer.

I guess we will see what happens - if the Octane engine really hits the RAM 2500 / 3500 platform in the next year or not.

It wont be in the pickups any time soon if at all. Also MPG directly relates to range you cant have high range with low MPG lol

 

[HarryN]

This is the most recent news that I have found on the octane engine and how cummins is positioning it in the market.

https://www.fleetequipmentmag.com/cummins-b67-octane-gas-engine/