6.4 getting a make over or going away?

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ramffml

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Big trucks are straight six because they have diesels. Straight six is the strongest, best balanced, of all engine architectures. No splayed journal bearings. So they run the cylinder pressures up to the moon. Can't do that on spark-ignited engines. Can only whiz them to high rpm. A straight six is overkill for a gasoline engine - V8's have the most compact architecture to pack more cylinders into the smallest volume.

Which is why I call out Stellantis for trying to put a BMW sport sedan engine into a pickup truck. It's all about fuel mileage now - not about durability or towing.

This is outside my wheelhouse, but I always thought straight six made a lot of sense in trucks? Towing is a big part of truck duty, same with durability, I would sooner suggest the high revving v8's we have now in half tons make more sense in sports cars like the vette, charger, and mustang (which is where all halfton v8's are currently as well).

But what do I know. I just want more towing oomph, don't care about 0 to 60 in the slightest.
 

HEMIMANN

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This is outside my wheelhouse, but I always thought straight six made a lot of sense in trucks? Towing is a big part of truck duty, same with durability, I would sooner suggest the high revving v8's we have now in half tons make more sense in sports cars like the vette, charger, and mustang (which is where all halfton v8's are currently as well).

But what do I know. I just want more towing oomph, don't care about 0 to 60 in the slightest.

What kind of truck, is the question. For consumer pickup trucks, no. The old, frugal Ford 300 cid I6 was a dog that didn't do much, but you couldn't kill it. Well, duh! Cause it had no power and was wasn't over-pressured.

I use the example of top fuel nitro drag engines as an extreme example - you can make north of 8,000 horsepower @ 12,000 rpm for app. 36 seconds of run time. Could tow a lot with that right?

Towing oomph = (1) diesel, or (2) larger displacement gasoline engine

Turbocharging a gasoline engine AND towing frequently will wear it out way before you expect it to wear out. If the turbo is ONLY used to tow occasionally, then it may live. See: Ford "ecoboost" twin turbo engines. They were great....for app. 70,000 miles for contractors towing heavily regularly. And that's it.

The diesel is built for, and expected to be subject to much higher duty cycle, loaded down frequently. The cylinder pressures are much higher (3,000 psi *** compared to 1,000 psi *** for gas), and as such, the engine is built much heavier to stand the higher loads or more hours. The inline 6 engine helps with this because each cylinder is supported by individual journal bearings - not split like a V engine block.
 

SouthTexan

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To be fair about the power levels of the 4.9L, all engines back then didn't make much power. My 1990's F150 inline 6 made 150 hp and my cousins 5.0L made 185 hp. Only 35 more hp yet it had more issues than mine. The 7.3L diesel made 180 hp in those years and the big 7.5L HD gas engine made 230 hp. I remember watching a power nation episode not too long ago where they modernized a 4.9L inline 6. With EFI and better air flow in and out, it made around 300 hp without increasing compression ratio.

There are also other inline 6 engines that are known for holding up to more power than V6 or V8 engine of similar displacement. Two prime example are Toyota's 2JZ and BMW's N and B series engines. The 2JZ is known for handling over 1000 hp at the wheels on stock internals and so far the BMW's are up to over 700 hp on stock internals. Primary reasons is due to their closed deck design (which is nearly impossible to do on gas V8's while keeping them cool) and their primary & secondary balance putting less stress on the crank and other internals.

In regard to the Ecoboost, as I mentioned previously, we have around 300 in our fleet and they get to 200k miles before we send them to auction. Many of them have an enclosed trailer hooked up to them 90% of the time towing upward of 7k lbs and we still get 200k out of the.

Do I think small turbo or NA gas engines (regardless of cylinder configuration) belong in an HD? No, the duty cycle of the HD trucks would create too much heat, however, they do have a place in half tons or even heavy half tons like my old F150HD that ironically had more payload than my Ram 2500. In the flip side, I do believe a large displacement engine, regardless of the number of cylinders or configuration, with a modest amount of boost or even N/A would be a perfect fit.

A large displacement inline 6 would likely not make more horsepower than a V8, but it would be easier to get more low end torque out of the inline 6 due to being able to fit a longer stroke. A longer lever(connecting rod) will always be able to make it easier to apply force to an object(crank shaft) than a shorter lever. You can get a V8 to make more low end torque, but you will have to make adjustments that would sacrifice top end power. The inherent design of an inline engine allows for a longer stroke while still being able to fit it under a hood. This is one reason why a V8 pushrod engine is better than a DOHC engine at making more low end torque. Due to it's design, the pushrod can have a longer stroke while still being compact and able to fit under a hood.
 
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Dusty

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This is the Hurricane he's referring to...
"The Hurricane will be a family of new twin-turbo, 3.0-liter I-6 engines..."

It sounds like there may be more than one HP version of the Hurricane motor.

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Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 79291 miles
 

Dusty

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I guess people forget about the Chevy 292 inline 6. Used in just about every HD truck back in the day. PS: Your Ecoboost Ford is a an over-rated POS, so use something else to compare to.
Just out of high school I drove a C500 for a local lumber company. As already mentioned the 292 was not turbo charged, and the maximum payload was around 18,000 if I recall correctly. Those had the torque, but pretty anemic on hills which often required generous downshifting. They also had split rear-ends.

Regards,
Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 79291 miles
 

HEMIMANN

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Just out of high school I drove a C500 for a local lumber company. As already mentioned the 292 was not turbo charged, and the maximum payload was around 18,000 if I recall correctly. Those had the torque, but pretty anemic on hills which often required generous downshifting. They also had split rear-ends.

Regards,
Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 79291 miles

I drove a Ford F700 ton and a half with dump bed using the same drivetrain set up for a landscape firm. To haul a load of dirt you had to use the low axle. What a bow wow!
 

Dusty

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I remember back in the day I loved those old Ford i6s. They would run forever and at the time made equal torque to the 5.0/302 v8s. The dodge slant 6 was also another one very hard to kill.
As a young person turning wrenches, I had a fair amount of Ford 300 CID experience since we serviced vehicles for the New York Central RR. The 300 was all guts, but very anemic, especially in the medium duty trucks. They were fairly reliable in that during my tenure we never had to replace an engine. But they had a propensity to be poor oilers, especially if you stretched oil changes. The most repeatable problem was cracked exhaust manifolds (sometimes an intake, too), and it was not a pleasant experience to replace. I never weighed them, but the older exhaust 300 CID (the ones with the heat riser valve) manifolds seemed to be heavier than a small block Chevy head.

Regards,
Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 79291 miles
 
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