Why do Semi-Trucks Use Inline-Six Engines?

[@Dustrunnersauto]

If you guys enjoyed the video, please SMASH THAT LIKE BUTTON. It helps the channel out a huge amount and helps KZbin put the video in front of more people. Thanks for watching 😬

[@warkal868]

Keep up the content. Thank you for amazing videos.

[@duncandmcgrath6290]

Great Channel 👍 this topic usually ends up a hornets nest stirred but worth it .

[@MyFabian94]

When people say that a i6 is more torquey or powerful or "has better power delivery" they mean that the even 120° between Cylinders makes for the smoothest Power Output on the fewest Cylinders. The first 30° after TDC and the 30° before BDC produce basically no Power as the Piston barely moves in the upper and lower 60°s. That means meaningful power delivery happens for 120° for every 720°. On a Single Cylinder this means that the Engine relies on inertia to rotate 600° for every 120° Power Stroke On a Two Cylinder this becomes 480° for 240° of Power On a i3 Cylinder this is 360° for 360° of Power And on an i6 it is 0° for 720° of Power. The Load on the Crankshaft and thus on the Clutch and Gearbox is far more even, there are no Interruptions in the Power Delivery. On a V6 you will often have two Cylinders firing within 60° and then 180°. This is uneven and felt in the Driveline. The i6 is thus the best in smooth Power Delivery for the smallest Size, as a V12 with the same Displacement will take up 50% more Space and weigh more as well while being less efficient all due to the Law of Cubes. These Engines are also running quite considerable Boost Pressures to make up for the low RPMs.

[@zweisteinya]

Fascinating. Wondering about rod length used

[@ryanrudd855]

In Europe we have v8 semi truck engines made by scania 500bhp to 770bhp

[@scrapperstacker8629]

I still drive a V8 Detroit. While I understand and appreciate everything you stated about an inline 6. I just love the sound of a two stroke V8 Detroit. The sound inspires me to go to work everyday. I always joke that I will retire the day that engine dies. It will probably out live me.

[@cliffordzellner5917]

What make and model is your vehicle that has a V8 Detroit?

[@HuugTuub]

Cam't have shit in V8 detroit.

[@mr_bear6362]

@@HuugTuub You’ve Exhausted your puns for the day

[@christophercain7343]

Two stroke Detroit’s are the single best device that turns fuel into noise

[@timnossem5538]

@@cliffordzellner5917 alot of boats use the v8 8v-71TA in single and twin configuration

[@bullettube9863]

As a former truck mechanic I preferred to working on straight sixes. You can reach everything from the sides without having to climb over the engine. The six is narrow so the frame rails are closer together without interfering with anything plus they allow more room for bigger tires and a tighter steering angle.

[@WISHBONEL7]

What do you believe is / was the best semi truck engine for longevity . Also , what do you believe is / was the best car engines ever made in terms of longevity ?.

[@bullettube9863]

@@WISHBONEL7 The Cummings 855 is a clear favorite, with a long record of reliability. The Caterpillar V-8s and straight sixes are also very reliable. The Detroit family are reliable as long as the temperature is above 40F. LOL they can be very hard to start when it's cold! Auto engines, Ford V-8s have direct oil lubrication to all moving parts. The GM 350 V-8 is probably the worse engine ever made! Any American made 4 or 6 cyl engine will be very reliable as after 50 years they have the design down pat.

[@WISHBONEL7]

@@bullettube9863 Wow , I am surprised to hear you take on the GM three fifty . Where does the early four cylinder or straight 6 Datsuns or Toyotas from the nineteen seventy's rank on your list ?? , as well as the Dodge / Plymouth slant or V 6 ?

[@bullettube9863]

@@WISHBONEL7 The Dodge slant sixes were very good motors, but mechanics found it difficult to adjust the valve tappets. The Japanese basically copied American and European designs, then improved them. They also copied American management practices, but American management soon corrupted itself with bean counters in the late 60s and as a result quality control soon became a joke. Example of this was the GM 348, which was intended to be a truck motor but with a 4 barl carb was used in the Corvette. For reliability it had four bolt main bearing caps and direct oil lubrication. When you see a 350 with four bolt mains, you are seeing a 348 block engine. The 350 was designed to be cheaper to manufacture. It's cam wore out at 50k miles, valve tappets wore out regularly and the timing chains just failed just when you least expected them to. They even made a GM tune-up kits which included the cam, lifters, gaskets, seals, timing chain and plastic coated sprocket, and oh yeah the spark plugs!

[@WISHBONEL7]

@@bullettube9863 How about the Ford straight six , and the Toyota twenty two R ? , or the older Volvos ? , in which I just wish that they had a timing chain rather than a timing belt .

[@drewncars9505]

As a heavy duty diesel tech I’ve never once in my life heard someone say that a paccar is their favorite engine lol. Paccars are for people who want a Peterbilt or Kw but can’t afford a Cummins or fleet companies who want to cut costs and run a cheaper (unreliable) engine. All of our KWs in the fleet unfortunately have paccars and they’re all significantly less reliable than a freightliner with a Detroit or an international with a Cummins. Other than that great video for teaching the basics to people that may not otherwise know much about big trucks!

[@rdsii64]

When I drove for Prime Inc. My T600 KW had a Detroit diesel. I'm not a mechanic so I can't speak to what is better than what. With that said, My truck was on time every time and never broke down.

[@B0RN2RACE100]

Only people who buy paccars are desk drivers that look at numbers of cost vs breakdown time and make a decision on how much the company is going to make and discard the possibility of a stranded driver by the side of the road as long as it makes sense mathematically to fleet.

[@wizard_of_poz4413]

@rdsii64 detroit got acquired by Mercedes in the early 2000s followed soon after by freightliner. Before that you essentially had the pick of the big three engines in all trucks

[@gailgrove]

As another diesel tech I agree 100%. DD15s and ISX15s are the two most reliable engines on the market right now. Volvo/Mack also make a good engine with more electronic issues. Paccar is the worst on the market, at least since the Maxxforce went away... Gotta love the older engines when I see them though, C15s and Series 60s are still very good engines.

[@JayElement13]

@@gailgrove lol I don't know about reliability I've worked on shit loads cummins isx15 cummins isx isl and isb have kept me well paid for many years they keep cummins back for repairs

[@kalle5548]

Scania (a Swedish truck manufacturer competing with Volvo) does still develop and mass produce their V8 lineup, they are euro 6 compliant and produce 770hp and 3700Nm (2730 ft-lb), but most importantly they sound absolutely amazing, they have most likely survived because of the requirement for powerful engines whilst hauling logs in the somewhat mountainous north of Sweden

[@brianmcauley3450]

They also sound ungodly cool when u put a straight pipe on it

[@gpsx]

I saw a video about a truck study Scania did years ago. If I remember they concluded trucks are safer if they move faster with the flow of traffic (Or something to that effect). I'd guess that is why they produce such a high horsepower engine. In some of the most demanding applications, especially road trains in the hot Australian outback, they usually use engines rated at a lower horsepower for reliability.

[@johnnyhun1]

scania only making v8 for marketing reasons, there is really no need for v8, Volvo has the same HP and Torque ratio with an inline6.

[@kalle5548]

@@johnnyhun1 Yeah, but they sound cool as heck and easily produce 1150hp (stock for marine applications) and they somehow managed to burn 8 L/100km with a 30t load (perfect conditions)

[@johnnyhun1]

@@kalle5548 Its still not about how many cylinder it has or its a V or Inline, in that case bmw had 1,4 liter 4 cylinder engine with 1200 horsepower (m12) ... :D So technically V8 today is still pointless, but yea they sound cool :D

[@alsaunders7805]

For the same reasons my favorite engine in older Ford trucks was the 300 straight 6. Dependability, ease of maintenance, and lots of low end torque. 🤓🍻

[@petersipp5247]

Yes, I have been using the 240 cid Ford six motor for 31 yrs. No trouble, Easy getting to dist, plugs, water pump, alt. Am going to the 300 cid Ford six motor in Jan'y 2023. Brgs getting too loud.

[@juansarabia7530]

My Chevy 250 has max torque at 1600, versus big rig 1500. Not very fast, but if you want go fast, get a freaking sports car.

[@efrainzavala1919]

and how you said it

[@slysithejuicegy]

One point I would add to the list of advantages to inline engine's in trucks is being a narrower package provides more room for the large front wheels at full lock. For manoeuvering you often need all the steering angle you can get.

[@Stale_Mahoney]

this is also why we love cab overs in Europe, sure the nose trucks may look great but put that nose under the cab and not only are you sitting taller and have bether overview, but also the frame becomes allot shorter so the turning radius increase by quite allot

[@slysithejuicegy]

@@Stale_Mahoney same here in New Zealand. Slightly differently configured. Tractors have one or 2 steering axils with dual driving axils with locking differentials. A popular configuration is truck and trailer. Again twin steering axils and dual driving axils, 9m deck.. Pulling a 4-5 axil trailer. 2+2 or 2+3. With 12m deck.

[@clasher3355]

not really the wheels only barely stick above the top of the frame rails so it would take a pretty extreme engine design to block space that isn't already blocked by the frame or drag link

[@tntfreddan3138]

We have 385/65/22.5 on the front axles of all our trucks at the company I work for (315/70/22.5 on the driving axles and 385/65/22.5 on the trailing axle). Doesn't matter if it's a Volvo DC13K (13L I6) or Scania DC16 (15.6L V8) we still have a 13 meter turning circle. Btw, on our trailers we either have: 8x 385/65/22.5 8x 435/55/22.5 16x 245/60/19.5 We use 4-axle trailers with 2 axles in the front (these are fitted like a dolly onto the trailer) and 2 in the rear (fixes axles)

[@cliffordzellner5917]

@@Stale_Mahoney I do a lot of expediting here in the US and I saw a old black and white photo of a truck stop parking lot and they were all cabovers? And I saw an old photo of trucks in Europe and they were all conventional? Thought that was interesting.

[@barrymorrisss]

Back in the mid to late '70s, the drivers where I worked were bummed out that their 350 horse V8's were being replaced by 300 horse straight sixes. Their tunes changed when the sixes stepped out and passed them pulling up a local long hill.

[@cravinbob]

gasoline engines.

[@TheLionAndTheLamb777]

@@cravinbob What makes you say gasoline? barrymossisss is correct.

[@josephsteffen2378]

I remember my stepfather tow-truck at his repair shop. It had a 349 straight 6, and a super low differential ratio. I remember the mechanical whine that it made. My stepfather said it guzzled fuel. And that was in 1973, during the oil embargo. Hey sold it after the 1978 oil embargo.

[@984francis]

@@cravinbob Eh?

[@nojunkwork5735]

Besides, maybe Cat who was making 350 horse V8s in the 70s?

[@creedence1819]

When your pistons weigh as much as early WWII tank rounds, engine balance is super important.

[@Chris-hx3om]

Why does everything get compared to something about a gun? Are Americans penis's THAT small?

[@creedence1819]

@@Chris-hx3om who said I'm American? I can show you my dong if you're really that interested.

[@qx4n9e1xp]

You had a picture of the best BMW to illustrate your point for the i6 consumer car engines. 👍🏼👍🏼 My heart is warm, and my brain is nourished from watching this video.

[@steven44799]

one thing overlooked in the video is that the forces on the crankshaft main caps in an inline engine are mostly straight up and down, in a V engine the power strokes are on a 30-45 degree angle meaning you have much more side loading on the main caps that requires additional strength.

[@scottleggejr]

yea and intake runners, valve angles, and piston quench are better on a v8 design which all add to efficiency. The harmonic pulse of the power stroke of a 6 cyl hammers harder than sharing it over a bigger bore count. This is why tractor pulls use turbines.

[@JTA1961]

On a...side note...

[@justbinhumbled8207]

Very good point. I was along the thought that i6 engines run smooth and diesels by nature have a lot of vibration.

[@MrPizzaman09]

The inline 6 allows for big bearings, which helps when you have 200+ bar cylinder pressures. Forged cranks, rods and steel pistons are all a must. As a result, you get better thermal efficiency and thus higher fuel economy. Also, larger pistons and bores are more thermally efficient than having many small ones.

[@turbojoe9554]

yes but there is also parasitic losses that grow with bore size, and there has to be a balance between those losses and thermal efficiencies. As such, I-6 is still the least expensive overall option.

[@johnphillips222]

I am not aware of an OEM diesel engine calibration that has peak cylinder pressure of 200 or more bar. 150 bar is more realistic. High performance cals can be different, but OEMs keep peak cylinder pressures

[@MrPizzaman09]

@@johnphillips222 A lot of manufacturers are above 200 bar, especially in Europe. The US semis are already there too in the last few years. Once tier 4 hit, a lot of these engines kept going higher with cylinder pressures. The race is still on to go higher.

[@MrPizzaman09]

@Santa Claus No, 200 bar. Close to 3000 psi

[@hexagonosaurus5848]

@Santa Claus 2 bar is rougly the pressure of a car tire. Its a fucking combustion cycle dude. Its 200bar.

[@scotcoon1186]

Packaging is an issue for a v8 in a truck. A 3408's exhaust manifolds are outboard of the frame rails, which means the turbo has to go on top, all the accessories have to go on front, and the oil filters need to be remote mounted. An inline 6 has plenty of space on the sides to mount everything and still not try occupying the same space as the hood.

[@kalle5548]

In cab over engine configurations it’s a non issue, Scania still makes v8 for their truck lineup

[@orlandomoreno5326]

@@kalle5548 Scanias are small cabovers. Different stuff

[@sneakybohemiancreature2970]

.. Cabovers mean shorter wheelbase = Better Turning Radius Euro & Asia drivers don't live in their trucks Their point a to point b is not a continent Coast to Coast San Francisco Delaware Pennsylvania would benefit from cabovers with older narrower neighborhoods street designs like the older eons older Asian and Euro establishments ...

[@Carla-tz7qw]

Cab overs suck. Rough riding bastards.

[@Britspence381]

So interesting. I'm not a mechanic or truck driver but learned quite a bit about how engines work from this video. Thanks for posting!

[@switchinggears9389]

Dont forget. Big bores have removal sleeves for easy in frame rebuilds. Sleeves come matched with pistons as a set.

[@LionheartedDan]

In-line 6 are one of the few dynamic balanced engine designs. Other engines have to use counter weights to minimize vibration.

[@kevinm1734]

Boxer engines? Kinda the only thing they have going for them besides low COG in cars

[@peterdarr383]

@@kevinm1734 Boxers have a slight "rocking couple" the width of a rod bearing. BMW even added a "dummy piston" to get rid of this in their later models.

[@beckoningjinx1119]

@@peterdarr383 What about flat plane V8s or I4s. I know they have vibrations at high revs, but these big diesels aren't high revs. In fact some V8s use a flatplane crank over a crossplane crank to achieve higher revs without the losses from the counterweights.

[@peterdarr383]

@@beckoningjinx1119 From what I read about Stock Car Racing the Flat Crank weighs less so you can accelerate out of turns when on "short" tracks. On Super Speedways you use the Crossplane for smoothness and reliability. There's also an exhaust advantage to Flatplane, so, completely different headers. The l4 has all 4 pistons coming to a stop every 180* and the RATE of acceleration of the 2 falling pistons is FASTER than the rising pistons, maxing out at 72* instead of 90* which creates a tingling buzz on a motorcycle.

[@genesmith4019]

@@peterdarr383 I haven't noticed that in my 911S. The dummy piston in BMWs is behind the steering wheel.

[@anthonysgarage]

I'm not a big "diesel guy", as I really don't have the need for one, but I enjoy your videos, and I always learn something new when I watch one.

[@Avinadav205]

Unless you’re living off grid you do have plenty needs for rigs. You need parts, groceries, tires, fuel, furniture, building supplies, water, and so on right?

[@anthonysgarage]

@@Avinadav205 I'm talking personally.🙄 If I was pulling a skidsteer every day for work, I'd have a diesel. If I pull one occasionally, my gasser is just fine. I have zero need in my PERSONAL use of vehicles for a diesel. It would be a huge waste. I would be doing 13 quart oil changes on a truck I use to grab lumber from the hardware store occasionally. But don't worry, there plenty of weirdos out there obsessed with owning a diesel who do just that.

[@A_Cowboy_called_JackRabbit]

@Santa Claus bio, and ULS, are available here in the States. I use either at any given daily fill.

[@globalautobahn1132]

I thought I knew stuff about automobiles, but this was the first I ever heard that semi trucks have us in-line 6 engine… Learn something new every day! 👍👍

[@joegotz1971]

I used to run a Case 1370 with an inline 6 that ran at 2150 RPM. I also ran an Allis Chalmers with a Cummins V8 that ran at 2800 RPM. The Case ran a lot happier at low RPM and pulled better in tough conditions.

[@abrahamedelstein4806]

I've always thought the I-6 was theoretically the perfect engine configuration with the exception of space.

[@catinthehat5140]

Bmw 340i

[@vxsr33]

yes I-6 engine has perfect primary and secondary balance which is why they are so good and smooth. the only real drawback is the length of the engine which is why many manufacturers prefer to use V6

[@mikldude9376]

A bit nicer for doing maintenance on a truck too , for that reason alone a 6 would be my pick for a truck power unit . V8`s sound nice and are good until you have to work on them .

[@andrewdavis6012]

noisy

[@hanzen5174]

I6 have superior fuel economy compared to V8

[@gglen2141]

Be-yootifully explained. In-line 6 engines are simply the best. Speaking of 3 cylinders, I had a rental with a 3 cylinder and was amazed at how smooth it was. I bounced it off the rev limiter a couple of times by accident (not because it was a rental)

[@ItsKing32]

Sureee it wasn’t because it was a rental

[@theboyisnotright6312]

Ya just like I" accidently" did a bootlegger turn in a rental car once 😁. Fun as all get out but pretty rough on the car.

[@devonrosa4414]

@@theboyisnotright6312 forgive my ignorance, but what is a "bootlegger turn"? 180 degree e-brake turn?

[@ctretta]

​@@devonrosa4414 Also known as the "Starsky and Hutch 180"

[@mitchburk5112]

Just saw where Dodge/Ram/Jeep are going to replace the Hemi V8 engines with turbo in-line six engines in the next few years. Inline sixes with 7 main bearings are extremely strong engines. Had a couple of the old Jeep 4 liters based on the old AMC design. They ran forever.

[@turbo8454]

Interestingly the GM Atlas inline 6 was cancelled because of main bearing area. Being greater than the main bearing area of a similar size V6, the extra fuel required to overcome drag of the extra area was the main consideration. I got this info from a GM insider over 10 years ago.

[@vpotteriiixxx]

Till the cam broke the distributor drive gear and oil pump quit working

[@keithkuckler2551]

Ford used to make a 300 cubic inch in line 6, I had two F150's with this engine, with a four speed with overdrive. They were terrific, lots of power, and, good on gas, they were simple and ran forever, and, were easy to work on.

[@rickinoakville1549]

@@keithkuckler2551 We had an early 80's Econoline with the 300, pulled an equipment trailer etc.with no problems. When we went to an 89 econoline with the v8 302, didn't seem to have the same grunt power as the 300,

[@keithkuckler2551]

@@rickinoakville1549 Yup, I agree, that Ford six was also used in indusrial applications, in farm equiptment, ect. My current F150 has the 5.0 Coyote, and, it is great, but, an inline six with modern fuel injection, and, a 10 speed automatic would be a wonderful combinatiion. I just have no faith in those small displacement engines with turbos, too complicated, and, way too much to go wrong.

[@andrewt248]

I'm not sure that I would characterize the difference between high and low RPM motor designs by saying that there is "less stress" with the lower RPM design. Stresses exist in both, but are simply different. Lower RPM operation is likely slower to wear on components vs high RPM, but high torque output puts a different demand on parts and high torque, low RPM engines are generally designed with components made to handle that demand (much more robust than a high RPM engine).

[@wizard_of_poz4413]

Most diesel engines always benefit from low rpms because it's a slow burning fuel which means that longer stroke allows it to extract more work from that load of fuel before it goes out the exhaust. And with bigger bearings and pumps, you really multiply parasitic losses in a hurry as you climb rpms

[@edgarrodriguez5436]

@@wizard_of_poz4413 yes especially in the 6 in line engines have a low rpm compared to a v8 Diesel engine with higher rpm

[@jonasstahl9826]

Many force increase in square not linear means double the RPM you have four times the forces.

[@michaelf.2449]

@@edgarrodriguez5436 and their is limits to what the fuel can actually do. It burns at a certain rate and higher rpms and diesel just don't mix well without alot of bandaids

[@pauld.fisher8461]

@@edgarrodriguez5436 ... , heh, heh ! The Cummins 903 V-8 from long ago cranked 2,800 r.p.m.'s from the factory . . ... .

[@Bogie3855]

These engines were originally used in tractors because of the bottom end torque. That and they are pretty much indestructable. Not fast but reliable and loads of bottom end. Fit in a small space too.

[@stevelarson1236]

Cool. I wondered about this for a long time. It seems that the in line 6 gas engines of the 1950s lasted a long time. I think the V-8s came along for more horse power and the Muscle cars.

[@sootmann]

I would guess that an inline engine is also quite a bit cheaper to manufacture than a V, and easier to design. One set of pistons all in a straight line, one exhaust, one intake, and fewer space constraints on the intake and exhaust sides. You don't need to make the intake manifold fit into the valley of the V. Also, since heat rises, an intake manifold (and associated parts) are probably under more thermal stress in a V, whereas if it's off to the side of an inline engine, there's a little less, plus you have more room to cool it. Some of that might be totally off base but I'm sure at least half of it is correct. :-)

[@sneakybohemiancreature2970]

.. Marathon not quarter mile qualifier ...

[@mjwbulich]

It was my understanding that they were more expensive to produce than a V8. The machining of the block and head and the need for longer stronger crank and cam shafts more than offset any savings on other components This was something a GM engineer told me many years ago. With advances in technology it may not hold true today.

[@rtwice93555]

I think you pretty well covered it. The majority of the trucks in our fleet spend their day idling to drive the PTO. Torque and horsepower aren't nearly as important since they only drive to and from the jobsite. Its not uncommon for some of our ten year old trucks to have only 20,000 miles but have a grip of hours. You summed it up best when you said they are easier to work on. Since I generally work alone, setting a cylinder head on an inline six does take time guiding it on straight with a hoist. But at least the block is level. I couldn't imagine trying to do it on a V configuration where the head would have to be angled 45 degrees. Also, driving pistons into a 6 is nice because the rod hangs straight down. Doing it on a V engine would be difficult to do alone because the rod would tend to fall to the outside of the cylinder.

[@kfelix2934]

So true I scan my cat c7 computer it dranked over 60k gallons of diesel in it's life time and most of that was at idle. 😀

[@Mywhtjp]

More fuel efficient, but less productivity. That sounds like over engineering to me.

[@TA_Plus_Hemi]

I don't know anything about diesel engines and I'm not going to pretend I do but when it comes to 6 cylinder gas engines I am more of a fan of the Jeep 4 L inline 6 or the Ford 4.9 L inline 6. Basically all of the characteristics that you described other than a full rebuild seem to apply to both. As far as the torque I feel I6s tend to deliver it more smoothly than a V6. It might be personal preference though.

[@Mywhtjp]

Yep and with less rpm's. My '99 Wrangler had that inline 6.. quite torquey for offroading.. She now has a small block 318 magnum.. Still torquey.

[@shelliecarlson7015]

Chrysler's slant 6 was an efficient, high mileage beast.

[@jimjamauto]

The carb'd versions of the Ford 4.9L made peak torque at 1500-1600rpm which is totally absurd. PowerNation has a video series where they build one and dyno it several times, the torque curve is super linear and always much higher than hp even when they add a turbocharger. The big difference is that the 4.9L likes to be at a medium-high RPM when doing work.

[@wesleygray5349]

You guys just hit 3 inline 6 banger engines on the head for me. Learned to drive on a 1966 Fargo (Dodge) A100 window van, with the 225ci slant 6, sporting a 3 on the tree standard transmission. I still own a 1979 Ford E150 Econoline van, with the 300ci (4.9L) inline 6. Currently I am searching for a replacement for my 1989 XJ Jeep Cherokee, which I was able to save its engine, a 4 litre MPI inline 6. Looking for leads on XJ with good body, in Toronto area!

[@benharris7358]

the Ford Australia Barra I-6 is also a distance beast with many taxi's using cars with the engine racking up over 1 million km

[@brucemoberley3355]

lighter crank and camshafts, less heat rejection with larger cylinder volumes, no counterbalancers, potential for reduced turbocharger back pressure ( optimal pressure wave overlap with proper turbo type and sizing) All lead to a hard to beat BSFC unless opposed pistons are used- even less heat rejection and potential longer expansion for given size engine. Rotary sleeve on intake ports could take this expansion even further.

[@ObservationofLimits]

A straight six is going to have a heavier crank than an equal displacement V6. The fuck are you people going on about incorrectly with weight.

[@scottleggejr]

@@ObservationofLimits All that cam twist got their timing thrown off... Or maybe it's the intake/exhaust runner lengths? Or maybe valve angle?

[@ObservationofLimits]

@@scottleggejr who knows

[@stacyp4534]

The Detroit 8-V92 with a super charger and 2 turbos will never be beat. That was the most awesome motor ever made. We had 2 of them on the farm to haul hay on double trailers. They were 675 horsepower and this was in the 1980’s.

[@struedel25]

2 cycle Detroits did not have superchargers. They had roots type blowers. They were "scavenger" blowers, meaning they pushed the exhaust out the exhaust valve. They provided no boost. That's why they are not called "superchargers"

[@Carla-tz7qw]

They still can't be beat. No computer no plastic no def. Just you might go deaf. Lol love Detroit

[@Sam-ls6sl]

I have always liked the way an in-line 6 feels, from various bmw’s and Cummins I’ve driven, and even in a gas configuration, the good balance of torque, inherent simplicity and fuel economy makes it a nice platform and it generally sounds good too. I wish we saw more manufacture of it in the gasoline world today. Thanks for the video

[@gregking7926]

We used in the fire dept's I was in as a firefighter, 6-71 straights, then 8V71's. Those transited to 8V92's and 6V92's. We switched to Detroit Series 60's and Cummin's when the 2 cycle Detroit's were basically banned by the EPA( or so I understood). We did have a couple of Macks with Maxidyne''s but they were the exception to our use of the other two motors.

[@carlbrooks90]

Inline 6s are workhorse engines very durable and well balanced 🤤

[@vincezab1]

Great video. One correction though- the inline 6 isn't balanced because it has 2 pistons going down as one goes up - it is balanced because at any given time the number of pistons going up or down is the same. Contrasts that with an inline 5 where you have three pistons going one direction and 2 the other.

[@HoneyRiverRanch]

What about the 4BT Cummins it’s a inline with 2 piston coming up as 2 are going down and they shake like crazy

[@dre04mach]

@@HoneyRiverRanch thats due to the inherent imbalance of i4s, check out Driving4Answers video on explaining those. Also, this video is off, v8s dont use balance shafts...

[@levistrauss5378]

Finally an answer to the question I've had for years.

[@thepitpatrol]

Best explanation I have ever heard. We ran 300 sixes in UPS and you couldn't tear them up.

[@johnphillips222]

A better description is to say that an I6 is in primary and secondary balance. That plus the ability to do an in frame rebuild and a separated hot and cold side makes the I6 the dominant configuration. The torque-whatever leverage stuff is just a distraction. We design the mechanical packaging, layout, and structures for the engines that go into vehicles of all types. Sometimes the vehicle is based on the engine, and other times the engine and trans dominate the vehicle design. There are more I6 engine constraints due to hood visibility in commercial trucks. That is why we see sloped hoods. It makes a difference. The FEAD designs get interesting to help with the hood designs.

[@timothykeith1367]

The in-frame overhaul is a big factor

[@JC-gw3yo]

I am surprised to not see raked windshields. MFG's are stuck on 1950's design when all the rest of the rig is aero

[@NVMDSTEvil]

Now get the idiots designing these things to put the starter somewhere accessible instead of stuffed into the frame rail.

[@johnphillips222]

When it comes to raked windshields with the trucks we have to wonder if the engineers that spend their careers on aerodynamic improvements are that dumb, or is something missing when people guess about what works best in the wind tunnel? The windshield rake does NOT affect performance in the same way that it does to some degree in a car. How is the hood design for a truck so much different than that of a car?

[@melvinrexwinkle1510]

" The torque, whatever stuff is just a distraction" Spoken like a true designer that's never operated a class 8 truck. Torque is everything for a low rpm, fuel efficient, long lasting engine!

[@robwhite3241]

In Europe land V8's are more common because in cabover configurations a big inline 6 would be too tall so V8's are used for the heavy hauling. Scania's the most popular V8 over there

[@alexstromberg7696]

Every single volvo, MAN and 98% of benzes are inline 6s. Scanias v8 isnt even their best seller. That is a inline 6.

[@robwhite3241]

@@alexstromberg7696 I meant the more popular heavy duty diesel v8s . My bad!

[@ChromeStacks]

I love a Scania v8 I own a 164 myself. But that isn’t true. No one really uses Scania for proper heavy haul. They use merc MAN and Daf. None are a v8. Merc and man iveco used to sell v8S. And indeed most people by 6 cylinder Scania a as they don’t need the horse power. Scania arnt popular on proper heavy haul as u can’t get big axles like in other brands. Scania are know to have chocolate diffs and gearbox’s Scania still sell a V8 because enough people still like them and buy them. But notice the fleet spec trucks have 6 cylinders.

[@robwhite3241]

@@ChromeStacks I stand corrected! Ive seen the Australian heavy haulers use the Mack V8 so I assumed the same was true in Europe. So owner/operators are the main ones who buy them over there? also that's a shame about their axles, Mack should have shared their world renown diffs and axles with them.

[@alexstromberg7696]

@@ChromeStacks here in sweden they do

[@pattyjay9999]

Volvo also has or had a 16 L engine the D16, the truck I drive is equipped with this motor, no longer available in the, US 600 hp 2200 foot pounds of torque very reliable fuel efficient.

[@jimmy_olds]

They had a lot of issues, at least at the beginning

[@MrPizzaman09]

And used a ton of Def

[@terjebetten3854]

The D16 is still delivered in trucks here in Europa. The biggest D16 has 750ps, and 2600 lb-ft. Biggest problem with our D16`s is fuel consumption. The D13 is a much better engine if you don`t need 750ps.

[@johnwyman6126]

@@terjebetten3854 you live on Europa?

[@hoost3056]

The D16 was a problem child compared to the VED12, D12 and D13. Don't understand how it happened since the platform was the same.

[@quadsman11]

100% on board with you ! Even to include the Ford BIG SIX 4.9 GAS, and the GMC 292 BIG SIX GAS ! Both have ALL of the same benefits as their BIG brother's diesel counterparts ! And for exactly ALL the same reasons ! In a word, durability ! And yes, plenty of room between the rails, unless you have a need to get into heavier machine work, for the grand majority of repairs, and even rebuild work, it can ALL be accomplished while remaining in the chassis ! Balance, and hearing surface area, ALL create that be ALL, to end ALL, LONGEVITY factor ! Which equates to profitablity to both the private long haul driver, to the BIG commercial fleet owner ! Great video Sir !

[@michaelwadsworth4170]

Have no CDL, Yet own four I6 engines in Jeeps and Volvo road cars.They last forever. Volvo even has a "million mile club" w/ many members. This vid will be fun to share with friends who have had to overhaul 4-bangers and V's simply for balance issues. Keep up the good work, Brother!

[@skcyclist]

Such an interesting video. Thank you. Not to compare exactly, but the car I learned to drive in was a 1949 Dodge Meadowbrook with a flathead inline 6 and about a hundred horsepower. It had a fluid drive and you want to talk about slow off the line, that was it, but it also could be shifted manually with three speeds. We mostly used second and third. But it was possible to come to a full stop in third without pushing in the clutch, hence fluid drive. My 5-ft tall mother also learn to drive in that beast. No power brakes no power steering and my mom could barely see over the dashboard, but somehow we survived. Hey, I even remember the license plate fxb 921. Dad remembered because there was an actor Francis x Bushman back in the day.

[@ccole9080]

My dad bought a brand new 52 Dodge Meadowbrook w fliud drive ,my mom learned how to drive on it, he sold i to my uncle who drove it for years. Later on my dad bought a 53 Meadowbrook , w fliud drive . We never had any tailgaters in that one , it was like a blue fog bwhind us at all times . The engine was so sludged if you ran it with more than a trace of oil on the dipstick you couldnt see out the back window. The old girl ran for 15 years. Slower than a turtle for sure

[@skcyclist]

@@ccole9080 Great stories. I believe they were all flat head 6's with around 100 HP. Yes, tortoise slow and often oil burners, but I believe somewhat reliable. I seem to recall Vern at the 76 station bought ours and lost it in a poker game for $25 c 1962.

[@ccole9080]

@@skcyclist lol ... slow . oil burners . flat head I 6s , reliable.. the answer is D.. all the above . . Love the story about your family selling it to the 76 station owner who lost it in a poker game for $25. Our 53 wasnt worth 25 when my dad bought it , we sold it in 1967 for $10 to a kid up the street , it still ran, $10 was scrap value . Is saved us the time and gas to drive it to the junkyard. I remember when we got the 53 the passenger front and rear floor boards were partially rusted out . a board and a rubber mat barely covered the holes and if you didnt lift your feet going thru deep puddles you were getting wet feet . Although my dad could have easily afforded good cars , he rarely bought them . When it came to cars he war tighter than bark on a tree

[@ccole9080]

@@skcyclist The 52 Meadowbrook was the first , last and ONLY new car he ever bought . Several times my Mom asked him to buy a new cars as for years he drove nothing but old junk. His response was I will when the kids get older . The kids are in their late 50s and 60s now and both parents have been gone for 25 years. Im trying to figure out how much older the kids had to be ? 😂

[@skcyclist]

@@ccole9080 I have never bought a new car. My dad never bought a new car though he got a deal on a pretty new Circa 1971 Plymouth Scamp demo car. We did not have a lot of money. Even when I could eventually afford a new car, I knew it would be a ripoff the minute you drove it off a lot. Everybody knows it. My mom was 5 ft tall and weighed 110 lb and learn to drive that heavy no power steering or brakes stick shift Dodge, bless her heart. I admit when I was in the backseat watching her drive I was pretty worried.

[@jdogdiesel7242]

Mack mp7 is the exact same as a volvo d11 Mack mp8 is a volvo d13... And back when they still made em the mp10 was the same as a volvo d16 The engines are made on the same assembly lines in most cases. Any sensors , gaskets , bearings etc that you order for a mack mp series engine will say volvo on the package. Since late 2007/08 all mack engines are volvo. Mack mdrive auto transmissions are actually volvo ishift transmissions... The list goes on and on...

[@highlypolishedturd7947]

I've been saying for a while now, Mack and Volvo are becoming the same truck with different cabs.

[@jdogdiesel7242]

@@highlypolishedturd7947 volvo bought out mack in 04? But they stayed all mack (renalt) untill late 07/08 then volvo put all their engines in em (mp series) but kept the mack maxitourqe transmissions and mack top loader drives....then they did away with the mack transmissions a few years back. Now its ether a mdrive auto (volvo ishift) or if its a manual then eaton is the only other option . So for Goin on more than afew years now the only thing mack is the cab/chassis , axles and the dog on the hood lol

[@DMTruckSpotting]

@@highlypolishedturd7947 they pretty much are. As a truck spotter, I notice they use the same components such as fuel tanks and DPFs in the same arrangements on the chassis.

[@highlypolishedturd7947]

@@DMTruckSpotting Yup, I see that too! Tanks, battery boxes, etc..

[@-DC-]

@@highlypolishedturd7947 Volvo and Renault trucks in Europe have a similar set up order a Renault and it's basically a Volvo with a different cab on top.

[@daltonkeener8107]

The Paccar PX7 and 9 are simply cummins engines painted grey with a different valve cover.

[@robwhite3241]

Same with the mack engines. The MP8 is basically a Volvo engine

[@Arclite02]

I own a 2021 Sierra with the 3.0L LM2 I-6 Duramax. I've owned and/or driven examples of just about all the V8 powerplant types available in the pickup market at various points over the last 20 years. I can think of maybe... MAYBE one of those that stacks up against this little I-6. Maybe. And not a single one of them can even dream of touching the same fuel efficiency. I absolutely LOVE this engine.

[@richardlug6139]

I am with you on that. Even with gas being over a $1 cheaper I will not go back to a gas 1/2 ton . The added torque and fuel economy is untouched.

[@avega2792]

I use to love the old 2 stroke Detroits. I didn't ride the school except for going on field trips, so the highlight for me was listening to those Detroits the whole way! When I started driving trucks in the early 2000s my favorites were CATs. I could tell them apart by sound and smell. Sometimes I miss driving them but I moved on from driving.

[@paulw.woodring7304]

I'm a lifelong railroad fan and former railroader. Until the last 15 years or so GM's former Electro Motive Division (EMD) always used 2 cycle engines in their locomotives. You could always tell the difference between their engines and those of GE and earlier units by builders like ALCo, Fairbanks-Morse, and Baldwin, which were all 4 cycle. Their passenger F40PH 3000 hp V16 model 645 (for cu.in. displacement per cylinder) for Amtrak was one of the most reliable prime movers ever built. Amtrak had them setup to generate hotel power for the coaches, so they ran at full-throttle (about 900 rpm) constantly when on a train, gaining the nickname "Screamers". The downside of the 2 cycles was worse fuel efficiency and more pollution, which is why they are no longer being built. Lots of railroaders need hearing aids today because of them, but I miss the screamers. They sounded like they meant business when you heard one coming into a station for a stop, never idling down. Two-cycle EMD 645s remain extremely popular in the used locomotive market for their durability and reliability, while hardly anyone rebuilds old GEs.

[@XX-nw1xg]

scania has the coolest trucks, those V8s are just mental

[@TakeDeadAim]

I love the 3.0L I6 in my new GMC Sierra. Very smooth and trouble free so far at 48k. Awesome MPG(Averaging 26MPG even running winterized fuel).

[@camsteremail]

I have a 2021 at4 she just turned a year old a few days ago. Only have 16,058 miles on it. I haven’t towed yet but I wondered if you have towed and what’s ur experience been if you did?

[@ronaldferrisjr]

I just hit 26K with my LM2 Duramax. This is by far the best engine I’ve ever owned. I can’t believe the power from this little 3 liter. It’s also smooth and efficient. I have the AT4 and have seen on average in the NorthEast 26MPG I did hit a best once of 33MPG but that was short lived. I agree with a the points in this video. My dad had an 82 Ford CLub Wagon with a 4.9 liter inline 6 302. This engine had 300k on it when he finally got rid of it and was extremely smooth. I wish GM could convince more people to buy this diesel for me it was a much better buy than the 6.2 V8.

[@Arclite02]

@@camsteremail Got a '21 Elevation with the I-6. The family's 18 foot dump trailer with about a medium load was pretty much trivial. Kinda wrecks that WONDERFUL cruising fuel efficiency, but even under load it's quite efficient.

[@BrianKrahmer]

I have a '21 Sierra with the same engine. At 9k' in the CO mountains, averaging around 32. Pulling about 7k#, down to about 15mpg. Excellent trailering vehicle so far, but lots of software bugs in the truck

[@Tchristman100]

The real main reason 6 cylinder engines are exclusively (at least in USA) being used is that all 6 cylinder manufacturers make the engine with intake on the left, exhaust turbo on the right facilitating any of the engine manufacturers to be installed in a truck with minimum modification. You can install a 11 liter up to 16 liter in just about the same area.

[@TheBlibo]

I recon you just about covered it but over here in the UK and Europe we have merc V6 and Shania v8 both just as reliable as the inline sixes Keep up the good work

[@carlschneider689]

Drove a '76 280-Z for a couple years. Loved the in-line six!

[@randallkelley3600]

Engine wear isn't really based on rpms but piston speed (or the velocity moving metal parts rub against each other). A low rpm engine can still have high wear if the pistons have a long enough stroke.

[@wazza33racer]

exactly correct, the devil is in the details

[@louiewiessv5756]

Yes!!

[@Stale_Mahoney]

well you are speaking of cylinder wear not bearing wear, now in my experience the later is more common.

[@clasher3355]

another important consideration is that these engines are generally built with bigger heavier parts in order to handle the torque they are expected to put out. it is in fact somewhat misleading to say that the low rpms are what lead to reliability when in fact it is more to do with the parts simply being of sturder construction. This heavy design is also the reason for such low rev limits since the heavy parts can only be moved back and forth so fast before it would begin to put too much strain on everything else

[@wesscarey4475]

Thank you Randall for pointing this out. "piston speed" is very important and often overlooked.

[@Sparky-ww5re]

I always thought was a combination of engine bay constraints and manufacturing economics that began to spell the end of the inline 6 beginning in the mid 80s, when American cars went from rear wheel drive, body on frame and very long hoods, to unibody, transverse front wheel drive and more compact cars, so manufacturers figured it didn't make as much sense to keep the I-6 when a V6 and inline 4 could be used interchangeable with minor modifications.

[@straycat1081]

Great video! Your style of teaching kept my attention the whole time, which is a tough thing to do. I was sad to hear about CAT no longer producing truck engines. Their two best engines in my opinion were the 3406B and 3406E with the B model being my favorite. I have a question about gas engines maybe someone can answer. Why is it nothing sounds like a V8? I mean, regardless of displacement or RPM, the V8 has a very unique sound compared to any other engine configuration. I have heard drag bikes with V-twins come pretty close at high RPMs.

[@dylanboyd6147]

I believe it has something to do with the irregular firing intervals of the pistons due to the offset of the pistons. With straight 6s, V6s, straight 4s, and basically every other engine configuration, The intervals are the same between each cylinder firing. They all give off a single tone whereas with V twins, you get two bangs 90° apart followed by 270° of not firing and you get that unique mix of high and low tones offset from one another. Same deal with V8s just scaled up a bit. The firing order of the cylinders makes it so that the time from one cylinder firing to the next is not always the same.

[@davidreeves2911]

v8 sound is because the pistons fire unevenly between banks even though each ignition stroke is evenly separated on crank rotation. 1-5-4-2-6-3-7-8 as an example would fire [left right] L R L L R L R R. different firing order or crank such as flat plain give different distinctive sounds. The v twins if they are Harleys have an uneven firing sequence of 0, 315, 405 giving an uneven pulse to the exhaust.

[@razorhook5421]

Yep like they said uneven firing and the crankshaft is 90 degrees out versus European v8’s and 12’s on lambos and what not have that high pitch formula one sound because their cranks are 180 degrees out big sound difference to American v8’s

[@straycat1081]

Very interesting, guys. Thanks for the informative replies.

[@michaelclark9762]

@@razorhook5421 180° engines are flat-8 or flat-12, not V. The reason they have that high pitched sound is they can run at ungodly high rpm because they are perfectly balanced without any need for counterweights.

[@donald7212]

You've told me nothing new we older guys have known about this for a long time.....,glad you now know, keep learning

[@wesm3915]

Back in 1986 I had an F550 bucket truck that had a 300 6 in it, I needed more power because I carried a lot of tools and pulled a 24' trailer with a 64' crane on it that weighed 12,600 lbs before I loaded signs on it. I looked into putting a 390 industrial engine in it but could not find the right transmission or tail shaft for the smaller drive line. I was in Mobile Alabama at the time and found Bob's Speed Shop, he said why not beef up the six, I had never heard of doing this, he made out a list of parts that included a Holly dual port intake, a Holly four barrel 550 with vacuum secondaries, tuned headers, a moderate high lift cam, dual points distributor and a Holly high voltage ignition coil an wire system. The parts were just over $600 back then which was a seriously lot of money for me. Knowing my way around an engine I tore into it on a Friday morning, and by Monday morning the beast was Alive. I had a 302 Boss in Mustang in high school so I had been around powerful cars and done some racing but this 6 cylinder came alive almost to the point of being scary, the engine sounded like a diesel and most people thought is was. The truck weighed 18,400 lbs loaded ad the trailer weight of 12,600 lbs, then signs of usually 2,000 lbs totaling +/- 33,000 lbs behind a straight six, it was crazy but that thing was a monster, I drove that rig all over the US servicing and installing signs for over eight years without a single engine related break down. Before the mods I was getting 10 mpg empty and 6mpg with trailer and couldn't hardly pull up a steep driveway. Afterwards I was getting 14 mpg empty and 11 with trailer and hills were no problem, pulled that thing all over the Rockies in Colorado all the way up to Montana. I couldn't figure out how to put a picture of it on here.

[@AndrewMoizer]

This is a really interesting post, thanks for sharing the info. I have a '75 Ford F150 with the 300 6. I kind of inherited it as a project truck. I'd always thought about swapping the engine for something more 'modern' to get better fuel economy but now it seems I should just upgrade the engine that's in there. I'll be saving this post and doing some research.

[@danielkennedy1524]

Great video! Ironically mack and CAT made V-8s. The mack even made a slightly different(longer) cab to accommodate the monster! Thanks for the cool info.

[@allan1062]

Cummins also made V8 diesel engines.

[@donaldhalvorsen4135]

The in-line six engine just makes practical reliable sense, more main bearings, and smoother running conditions.

[@cesargallo7424]

Also in farming equipment, where tractors pull hard at low speed, 99% are inline 6

[@onlyjoshing]

The only peice of equipment I've had that isn't a i4 or i6 is a Terra gator, which has a CAT v8.

[@MrPizzaman09]

The biggest John Deere tractor uses a Cummins X15

[@kfelix2934]

Most of the sml-to-medtractor are 3 cyl inline, only the biggest tractors have more than 4 cyl on average. So I think your avg% is totally wrong. I 've only been in 1 tractors that has had 6 cyls in my life operating tractors. Our JohnDeere 5090 is a 4cyl Turbo, but my JohnDeere 1120 is 3cyl NA, and my Newholland is 3cyl Turbo None are nowhere near 6cyls and the 5090 90hp is a big tractor for avg farm in the USA. These tractors are from 50-120hp power range fwiw. Also iirc Lamborghini ( yes , Lamborghini started as a tractor company ) , had more than 8 cyls iirc in their agriculture lineup at one time but that model cease to exist and was pulled out of production. Another factor that should be explain, the diesel engines are design for long stroke and low rpms that are typically below 3500, so they don't need more rods, pistons, more crank length to add to even heavier rotating mass. The bore to stroke ratio is quite large.

[@cesargallo7424]

@@kfelix2934 ok, can you please share the accurate % so we all learn?

[@kfelix2934]

@@cesargallo7424 Get for real, go to a ag dealer and see just how many inline 6 are parked on a lot for sale or trade-in, and then you can compute if 99% is a good estimation. Btw the biggest tractor on the planet is power by DD and it's a 16cyl vee configuration in the format of 2 vee 8. The 2nd and 3rd largest are vee formats also 12 cylinders iirc. The claim of "99% are inline 6" , is no where being correct or accurate. Even the the larges of ag-tractors are not inline 6s.

[@twinchantillytiffanysbenny8852]

I have a 2007 cummins mega-cab and a 2007 BMW 328 non turbo. Both have straight 6 cyl. Both have been super bullet proof and reliable. Also they both have that wonderful sweet torque! My cummins can pull a house! My BMW is a sweet rev-er. My truck gets 17/21 mpg AND it’s lifted on 22s”. I will never sell either one. Love the straight 6 engine, for torque and performance!👍

[@wcsii]

All of this bore’n & stroke’n talk..... gots me all hot and gooey!

[@El_Chompo]

4:00 the inline 6 *IS* inherently better at producing torque. It has the most power stroke overlap of any configuration. I just learned about this a few months ago and it kind of blew my mind. The inline 6 engine design has overlapping power strokes. This means that more than one cylinder are firing at the same time, which gives you more power and torque for the same displacement. The firing is always overlapping giving you extra power. I6 has the most power stroke overlap, and the i5 has the second most overlap. So not only does the inline 6 make more power for the same exactly design engine only different cylinder configuration, they are also perfectly balanced, which means less loss of power to friction, longer life span because there are no vibrations to wear out anything extra. This is also why all of the best racecars usually have V10s or V12s, it's because since the i6 has the most overlapping power strokes and is therefore the best engine, the only way to make it bigger and still fit in a normal shaped engine bay is to put two of them side by side. That way you still get all the benefits of a inline 6, but with 2 side by side in a v12 you get that really compact rectangular engine shape that is great for fitting into engine bays, whereas if you just made a inline 6 twice as big, it would have a much harder time fitting in most engine bays. And since the inline 5 has the second most overlapping power strokes, V10 engines are also popular for racing. The inline 4 engine has exactly always 1 power stroke happening. They are perfectly divided into 4 stages so that there is always 1 piston having a power stroke. Inline 4s are great, my personal gripe with them is how much they vibrate especially at idle and low speed. They can never really be perfectly balanced, only by adding lots of extra weights for counter weights that takes away power. So when you put all that together, the most power overlap, the most powerful cylinder configuration that has ever been discovered so far, and also perfectly balanced so it's great for minimal vibrations and long reliability, it's a no brainer for the inline 6 to be favored in industry when maximizing the numbers is all that matters. This design gives you the most power and torque for the money, and the most reliably. If they didn't, they wouldn't be using them. V8's aren't bad, they have pretty good balance as far as smoothness goes, but they don't have the power stroke overlap of the i6 because they are basically 2 inline 4 cylinder engines and inline 4s have zero power overlap. This is part of what makes a v8 less efficient than an i6. You get less power from the engine for the same amount of displacement, weight, and size. V12s are really the best engines in terms of outright perfection of power overlap plus the rectangular shape for fitting into normal engine bays. But because trucks can design their engine bays around inline 6s and v12s would cost way more in maintenance, they settle for the i6 which while not as cool as a v12, it is just as efficient. The v12 just wins for the extra awesome sound it makes and for fitting into normal engine bays better than a i6 of the same displacement. But they are both perfect in terms of maximizing power stroke overlap and having perfect balance and no vibrations.

[@juansarabia7530]

V-8 have more overlap, wasting fuel.

[@RedBud315]

My 2.4 inline six in my 240Z was probably one of the best engines I ever had in an automobile. I preferred it over the 2.5 four banger of the newer cars. With the exhaust system I had(3 into two into 1) at low RPM it sounded like a small block v-8 and at high RPM's it sounded like half of a Ferrari. That was also why Ferrari used V-12's because it was basically two smooth running sixes-in-one.

[@RB-xv4si]

Eh, not really. Not as far as the crankshaft. A V-12 crank needs counterweights. And of course it also needs two camshafts. So it’s a lot more like two V6s than two I6s.

[@dottorb7054]

Was just thinking about that Nissan Inline 6

[@michaelclark9762]

I loved by '77 280Z with the 2.8L L28 and Bosch L-Jetronic fuel injection. Smooth power all the way from the low end to the redline.

[@michaelclark9762]

@@RB-xv4si Some of those Ferraris were flat 12s with each bank 180° apart. Perfectly balanced. They could run up to ungodly RPMs for the metallurgical technology available back then.

[@ChrisRobato]

These particular Nissan-Datsun engines have a direct lineage to Mercedes Benz straight sixes.

[@jonahfastre]

In Europe, where we mostly drive “cab on engine” trucks, V8s seem more common, as they’re less tall

[@rolandsieker2286]

I did look it up, and it looks like Mercedes-Benz recently switched from V6 and V8 to only inline 6. Then again, nothing in this video really explains this switch. If I6s are so great, why did they use Vs before? If it really is the space, why use I6s nowe?

[@jedisentinel1499]

Hey thanks for the tutorial! Explained very well! It’s the best all general purpose engine made. The Chevy 292, Ford 300 which I think had agricultural equipment usage. I’m a Toyota man but I’d for sure buy an old American inline 6 truck.

[@rp1645]

Thank you for this very important informative video. MAN I learned some new things on your brilliant break down. I also thought in my Humble opinion, that when you look at a large carrier, say (ABF or Hunt) many of the same trucks (semi) the Company BUYS. Taking into account what you said, I hope the company has someone like you that buys a whole fleet of exactly the same CAB & Sleeper layout. The Company is driving the assembly line output. What I'm saying is. Semi plants run a custom order plant. It's not all Robot line. There is still a manpower element to the Line. Say (ABF) is buying a fleet of new trucks, replacement of older less effective (has to have a scrubber or DEF) ABF is actually picking the NEW Diesel Engines that will power their fleet. The bean counters are looking at all the things. Like you said, more miles on the engine over life. How much fuel the (Semi truck) will burn. Most of these large carriers put the (10 speed) high/Low range transmission. The same on all there (Semi fleet) worked for a Large carrier and all there ( FLs) were identical. Engine & Transmissions, will say live in a Large forest harvest State. The Loggers love the Biggest 8s and an 18 speed transmission mated together. The Right gears for many miles driven on hills and gravel. I once drove out to a village for first Nations People on Vancouver Island Canada. It was 40 miles to town on gravel roads, the Logging company maintenance the Roads. The town used to have a big saw mill. Because it was Faster for ships to pick up lumber then back to overseas ports. The mill is GONE now, but the town lives on with a big Farm raised Salmon products, and sports fishing personnel and charter. The saw mill now is the base for setting up on building Farmed Salmon pens, then towed to local coves. But I'm just saying do see Logging (Semi truck) a whole different animal as far a Loads and roads that driven on.

[@dennissmith8199]

The best inline 6 truck engine ever built ir the CAT C15 NZ engine. I had two trucks with them and both ran 1.5 million miles before needing overhaul. The engine had an enormous amount of torque from 1100 rpm up, and when set to 550 hp were no slouches on long uphill pulls.

[@briancasey4917]

I also had two trucks with that Cat engine. It flattened hills 👍

[@JPWest020]

In Europe the Scania V8 is a really popular engine. It costs more and it’s less efficient on fuel, but it’s great unit.

[@lndrlmsmartin5621]

Also some Mercedes Benz and man got v8

[@JPWest020]

@@lndrlmsmartin5621 True. But MAN and MB have stopped producing the V8 for trucks for quite some time now. Ten years- maybe even more. The only manufacturer that stil builds V8 trucks is Scania.

[@tntfreddan3138]

For me it's 50/50 between a V8 and an I6. The Volvo D16 is one of the best engines on the commercial truck markets. It's a 16.1L I6 engine that, today, produces between 540hp (2650Nm of torque) and 750hp (3550Nm of torque). Combine that with the best drive train on the market, the I-Shift transmisson, and you'll have the best truck to have ever been produced. The Scania DC16 is also a really smooth engine. It starts as a 15.6L V8 that ranges from 520hp (2700Nm of torque) to 660hp (3300Nm of torque). Then there is the 16.4L V8. There is only 2 specs to pick from here: 730hp (3500Nm of torque) or 770hp (3700Nm of torque). The 770hp version is currently the most powerful commercial truck engine in the world. It stole the title in 2020 from the Volvo FH16 750 that had been holding onto that title since 2011.

[@MarkWright1963]

Educate this fool doing the video please

[@walkerforsyth6221]

Meanwhile in the North American market, Volvo's D16 was so problematic and unreliable that they discontinued it sometime around 5 to 7 years ago..

[@tntfreddan3138]

@@walkerforsyth6221 Meanwhile, here in Sweden, most heavy hauling companies either go with Scania DC16 or Volvo D16 because no other engines are as powerful or as reliable. At least the newer ones. I've never heard anyone complain that their D16 or DC16 spend too much time in the workshop. That's saying quite a lot since most of the company owners I know that drive Volvo usually only do full loads (62 tons with 8x4 truck and a 3-axle trailer) since they haul gravel or asphalt, and in this business it's rare to see Scanias with under 580hp and Volvos without the D16 engine. These engines exist purely because the necessity for more power, mostly on the Swedish market. This also mean that they have to withstand quite a lot of abuse due to very heavy loads and steep inclines. The most popular engine for Volvo is the D13, though, and I find the DC16 more common than the lower spec I6 in the Scania trucks. Even when Scania released the 540hp 13L I6, most companies still prefer the 520hp (lowest spec V8) engine because it's more reliable.

[@tommywallbanger]

Good video. For many years I thought displacement was the volume in the combustion chamber at TDC so basically just the space in the heads.

[@microcolonel]

RE: torque and power: power is all that matters in any application with a transmission BUT the wider the useful range of torques across RPM, the less complex the transmission has to be. "low end torque" is a means of reducing transmission complexity, but as your transmission trends toward CVT, your focus shifts to peak power or peak efficiency, both of which are solved with more square stroke ratios.

[@bayoudrummer9855]

I’ll...I’ll just take your word for it

[@microcolonel]

@@bayoudrummer9855 Why say this?

[@oliverroedel1111]

us is an island. out there you have mercedes diesel. great engines, running all over the world. i have an om321, 5.1l inline 6cyl diesel, pos ww2 engine. and it runs and runs and runs. over the world there are thousands of om321 and om352 engines still working.

[@kdw75]

My old '98.5 Cummins 5.9 is still running like a champ after 200k miles. It also gets better mileage than the newer diesels I have driven.

[@freedomisntfree_44]

Gotta delete these new ones to get mileage like the older trucks 🙄 government

[@johnphillips222]

That is the best fuel economy, because the consent decree took effect in 1999.

[@jacobstrutner8232]

And my 04 lb7 gets 25 mpg, more power, less cab noise, and smoother ride while having a higher tow rating

[@wizard_of_poz4413]

@@jacobstrutner8232 until both of them rot from road salt. Or all the breakdowns on a duramax break you

[@robwhite3241]

@@wizard_of_poz4413 not if you live in the south ps: If your Duramax breaks just keep driving it, this one paster in my town just keeps driving his even though its a 6 or 7 cylinder engine now.

[@vepko008]

You should do a video about the AWD systems and why they have so many gears

[@chasbader]

Awesome video! Mark's Mechanical Engineering Handbook has the formulas for different engine configurations. L6/8/12/16 etc. are all perfectly balanced in primary and secondary as their vector sums are orthogonal. Tesla realized that 3 phase motors had constant power because he understood the math. Inline 6 engines use the same math as 3 phase electrical machines. Cool stuff!

[@lqr824]

not really

[@chasbader]

@@lqr824 not really in what way? Ok, so 3 phase isn't orthogonal, but it does allow for a rotating vector, unlike single phase/split phase/0-180 degree crank placement. So perhaps I should have broken this down into multiple topics.

[@mikeb46]

All great info there. The balance of a six is a big issue when the pistons are that huge. You did a great job explaining why a straight six makes the most sense. When I saw the title on YT I was wondering how many good reasons and you touched on all the big ones. I was wondering if manufacturing issues came into play. I worked at a Chrysler plant where I learned that a V engine of any size is more likely to have air pockets in the block which means it must be rejected and melted down. Even with vibrators the V design is harder to fill completely when casting the block. But it occurred to me that big trucks have a much smaller rate of production so that really would not be a major factor. The ease of repair, balance, and narrow block all contribute greatly to why the I-6 has won over all other designs.

[@jorgerodrigogomezflores5711]

Scania makes a magnificent V8, it is a 16.4L unit that’s always competing with Volvo’s 16L I6 for the world most powerful truck title, with Scania currently leading at 770Hp, up from Volvo’s 750Hp. Mercedes-Benz used to make a V8 too, discontinued a few years ago.

[@andersconstantin6988]

Add to that 3700Nm (~2700ft lbs) of torque. It's certainly a very mainstream exception to the more common I6.

[@patrickporter6536]

V10 also

[@ThePaulv12]

I'm a qualified mechanic and a professional truck driver. I have to tell you that almost all large truck engines I've driven are governed to 2100rpm from the factory. I cannot think of one that isn't so the RPM discussion vs stroke is irrelevant as you point out but irrelevant because of engine protection reasons such as missing a gear and over revving on upshifts. You still can over rev a truck engine but only on hill descents or if you downshift say 2 gears going down a hill with a heavy load on. Usually it is impossible to over rev a truck engine in neutral and when using the gas pedal - ie the engine goes to 2100rpm and stops. The principal reason the I6 is favored over a V8 is reduced pumping loss under light load saving on light load fuel consumption, increasing profits to the owner. It's about money. How the extra power is made up is by more boost. A V8 is always a V8 and those two extra cylinders increase fuel burn esp under light load compared to a 6 cylinder engine. Under light boost the inline 6 even at similar displacements to a V8 has a distinct advantage having two less cylinders. The V8 under light load conditions still has those two extra cylinders. It is very simple really. I have to say the inline 3 has a dreadful fore-aft rocking moment that causes bad vibration. They're a shocking engine IMO. I have a Mitsubishi Diesel inline 3 in a genset and the brackets crack, the bolts come loose, the cabinet doors rattle, the door catches wear out form the vibration etc. Check out Engineering Explained vid on the type: kzbin.info/www/bejne/hZSYkHVqhtqUlas

[@eatshitful]

What is a qualified mechanic? Oh i know it is your own made up term so you feel like you know something and other people just as dumb think you are some how smarter! 2nd clearly you have driven a very limited number of trucks if any at all if you have only seen them governed at 2100rpms and clearly no mechanic! 3rd How are you going to downshift a truck 2 gears and over rev it if you can't over rev it in the first place to get it into gear? Simply you cant You would have to drop them gears BEFORE gaining the speed and clearly you have never drove a manual shifting truck or you would know that! Now with the auto trucks im sure they will just not downshift or maybe upshift on you anyways because the computer will protect the engine not the driver. 3rd With that info you provided You are not any kind of a mechanic and at best maybe a low end driver for a company that will higher anyone they can squeeze into a CDL. Nice try tho trying to look smart kid.

[@michaelclark9762]

If two engines are running the same rpm, but one has a longer stroke, those pistons are moving against the cylinder bore at a faster speed than the engine with a shorter stroke. They're both taking the same amount of time complete a stroke, but one is travelling further than the other in that same time.

[@treyhart6861]

That inline six is huge.. look at the engine bay, it nearly spans the frame rails... Ok, now rock it over 90 degrees.. If they made a V8 with the same bore and stroke, it would be five feet wide. Plumbing is suddenly a lot more complicated.. two sets of cams, larger, heavier block and heads.. Heavier engines mean less available payload capacity.

[@electric7487]

Hence why Cat's C27 and C32 are at a 60° angle instead of 90°.

[@tesmith47]

YEAH LOOK AT THE SIZE OF THE PISTONS HE WAS INSERTING!!! I AM IN AWE BECAUSE I AM A 20,000 RPM F1 TYPE GUY!!

[@gregparrott]

Interesting summary. Another reason AGAINST using a "V" block is that it forces the block to become wider because the casting needs a lot of material in between the left and right bank of pistons in order to maintain rigidity. The 'valley' between the left and right bank of cylinders essentially represents wasted space and added weight. Several components grow with stroke. 1) Increased cylinder sleeve length. 2) Bottom of the sleeve has to be moved further away from the crankshaft to prevent crank arm from contacting the sleeve. 3) A longer stroke requires a longer connecting rod in order to maintain a reasonable angle of the connecting rod relative to the sleeve's centerline (represented at 5:17). Consider the dimensions (in inches) of the venerable Dodge 440 big block gas engine (4.32" bore x 3.75" stroke). If you've seen one under the hood of a muscle car the the Charger, it is one FAT/Wide engine. Just imagine how monstrously wide it would be if a V-6 was made with the stroke of the Cummins engine shown at 5:58 (6.65" stroke) . As a ratio 6.65 / 3.75 = 1.77. So, its width would be ~77% WIDER. The above relates to the REASON why inline engines typically have a lot of torque - the inline engines commonly exploit their inline geometry in order to increase their stroke without the commensurate increase in thickness of a 'valley' between the left and right bank of cylinders. An example of the inline's geometry being deliberately exploited is to compare the Ford 289 V-8 versus the Chevy 292 inline 6. Although they have the same displacement to within 3 cubic inches, just look at the difference in stroke Ford 289 (4.00" bore x 2.87" stroke) Chevy (3.875" bore x 4.125" stroke) The Chevy has over one and a quarter inch (1.255") greater stroke and it has a 44% greater stroke ( 4.125/2.87 = 1.44 )

[@Destilight]

I really like old perkins engines. Not particularly powerful or efficient but sure were easy to mantain and were really tough.

[@doodlebob069]

The paccar popularity number is most likely skewed as the px models are technically a Cummins engine with paccar badging. The mx models were designed to be in cabovers making them difficult to work on while being a unreliable and underpowered engine compared to the x15

[@MrPizzaman09]

Yeah, his numbers were not right. Cummins sells about 32-38% of engines in class 8 trucks, depending of the year. Freightliner sells about a third and then the rest of the engines split up the last third of the pie for the paccar, A26, and Volvo engines.

[@Sacto1654]

I think the smooth-running nature of a I-6 engine explains why it's popular with these big semi-trucks. In fact, Mercedes-Benz, which had been building automobile V-6 engines for a number of years, went back to I-6 engines because it was inherently smoother right throughout its rev range.

[@Radio_180]

The reason Mercedes is switching their V6s to I-6s is due to the decline of V8s. It’s becoming more economical to extend an I-4 compared to shortening a V8.

[@Sacto1654]

@@Radio_180 That too. Especially since Mercedes-Benz, like the Volkswagen Group, is starting to wind down ICE development in favor of EV development.

[@randyway1267]

So, this video is accurate about the lack of harmonics in inline six engines, but it leaves out that the number of main bearings in a V engine is cylinders/2+ 1, whereas the number of main bearings in an inline engine is cylinders + 1. So, an inline 6 has 7 main bearings, where the equivalent v8 would have 5. Both of these are nice to have, but the real advantage in an engine with a smaller number of larger cylinders is in the thermal efficiency. Longer strokes mean lower speeds, which effectively makes the flamefront faster, meaning that pressure peaks earlier in the power stroke. And, larger cylinders have a better surface area to volume ratio, meaning that less of the heat of combustion is conducted through the cylinder walls. Finally, the relative fit between parts is tighter in a larger cylinder. A five thousandths ring gap is a mile in a cylinder with a one inch bore, but is really tight machine work in a 6 inch bore.

[@NeoTesla]

Inline 6 engines have the most unique roar when they are straight piped

[@donaldkissinger7362]

Retired diesel mechanic I just love staying up on all the new stuff coming out I sure wish a lot of it was around when I was still in the field I'll tell you that thanks for the info.

[@sauertakedown]

Scania has 16,4 liter V8 with 770 HP and 3700nm torque. Beat that!

[@wrex7044]

They are also good for a million miles easy.

[@kartingwithmaverick0124]

Would love to see a video explaining the difference between an automatic and an automated manual. Every time I try to explain it to people they are generally skeptical.

[@trigger8152]

One is a dream to drive the other wants to make me smash the entire rig into a low bridge 😂

[@ccole9080]

in trucks or cars ? the ones in cars are NFG to put it mildly

[@paulblichmann2791]

Automated Manual: how to get to 10th gear as quickly and cheaply as possible, no matter how dirty, and just stay there all day. And when the city driver has to deal with the Automated Manual: "what are you complaining about, you have 'automatic'"

[@nathanramstorf1033]

Ahh yes. That damn clutch @ stops gets them every time. Big difference between them.

[@cedricpidde9314]

Pretty sure nobody would claim a Paccar as their favorite

[@TheIcyWizard705]

hey when they work they're pretty good, that and I felt a lot better idling with those engines and their much higher idle oil pressures when I need to run the AC while I'm sleeping

[@russellhalford8811]

Good info and a good video. My fav motor of all time is the Ford 300 I6. Low RPM torque is where it's at.

[@jasonjarnet8141]

This is a perfect video to explain diesel to car mechanics, great job

[@DougBennettActs6-1]

I would like to add that I believe the commercial truck people could improve with a slant 6. Fantastic config in the old Plymouth.

[@alexstromberg7696]

Scania has the most powerfull semi truck engine tho, that is a 16.4L v8 at 770HP.

[@Chris-eo4ry]

Inline 6 still better tho like the Volvo fh16 750 have a inline 6 that can tow 300.000lbs barely

[@SlavJerry]

@@Chris-eo4ry I would say maybe volvo is not more powerful anymore (for now) but it still have better at fuel efficiency

[@WaterandWoodsmen]

In-line motors are more fuel efficient I believe it to be a balance of rotation mass thing but I’m not an engineer

[@dand9244]

number of cylinders matters as well iirc

[@robwhite3241]

configuration doesn't matter as much for fuel efficiency but a long stroke and a lean burn is really what does it

[@ericblack6467]

Great video, very informative. Keep them coming. 👍

[@ditto1958]

Used to have a Chevy Trailblazer with an inline 6. Smooth and powerful with a flat torque curve. I liked that motor a lot.

[@bowez9]

Perfect example comes from Ford, 302 vs 300. In truck applications the 300 is superior in every way (more torque, mpg, and longevity).

[@turbo8454]

I owned both.....a 2WD F150 with the 300 six and an F150 4wd with the 302. Both had 5 speed manuals. Mileage was slightly better with the 302. More WOT power with the 302. The 300 six would lug a little better but overall the 302 truck was better on all counts and it was a couple of hundred pounds heavier..

[@bowez9]

@@turbo8454 like to know how was better with the same 140hp and the 302 makes less torque. Remember truck 302 were not roller motors nor were they H.O. motors. Would be curious to know which rear gears had If was only getting slightly better mpg then I would say using too much pedal. I'm willing to bet the 4wd 302 had 3.73 or 4.10 gears and the 300 had 3.27 or 3.08 gears, which would explain the perceived performance of tge 302 and you drove the 300 with full pedal to make up for the gearing difference.

[@turbo8454]

@@bowez9 Both trucks had 3.55 gears. Both were fuel injected (302 was a '94 and the 300 was a '95). Both were base model XL's. HP/torque as follows (manufacturer ratings) 302, 205HP @ 3800 RPM, torque 275lbs/ft @ 2400 RPM 300, 150HP @ 3400 RPM, torque 260lbs/ft @ 2000 RPM

[@bowez9]

@@turbo8454 205hp is the HO motor not the truck motor 140hp is what the non HO motors made with the Cobra and Tbird making 225-235hp. Dyno numbers for the 300 put it at 300lb-ft at 1200rpm. If those are Ford numbers then it's amazing, cause nothing changed on the truck motor and how did it go from 140 to 205? Marketing boys at it to push 302 sells in wake of the HO 302 being slower than the Tbird SC, so have to please the "Got to have a V8" crowd some how.

[@turbo8454]

@@bowez9 Not so. Truck was 205 HP, up from 185 HP in '93. Mustang was 215HP in the 5.0 in '94.

[@rightwingsafetysquad9872]

Semis can have low power because they are expected to operate in a small range of speeds. Torque does not matter when you're going fast, it's all about power. When you're going slow you can have either a lot of power or a lot of torque to get the job done. When you're going slow, more torque is preferable because it allows you to keep revs low, which is more efficient, quieter, produces less wear, and makes the driver feel like he isn't working the engine as hard (the last one is entirely psychological). But, if you have a vehicle that is expected to go both slow and fast, and transition between them quickly, going the high torque, low power route isn't feasible, which is why you'll never see an engine producing 600 ft-lbs and 300 hp in a sports car, but you might see 300 ft-lbs and 600 hp. And contrary to what a lot of diesel bros think, with the right transmission a truck with an engine that produces 300 hp and 100 lb-ft can do everything that a truck that produces 300 hp and 1,000 lb-ft can; but the former will be revving a lot higher, which means that it will be louder, less efficient, and won't last as long. Engine torque does not matter. It is wheel torque that matters. Thanks to transmissions, a high power engine can deliver just as much torque to the wheels at low speeds as a high torque engine; but the high torque engine cannot deliver as much wheel torque as a high power engine at high speeds. Some say that you need torque for beginning from a stop, but that's what clutches and torque converters are for. Having high torque, but low power also means that you either have extremely high pressures or extremely large displacement, in the case of semi engines, it's both. This means that the engine is going to be very heavy. Semis and large pickups (ala Superduty) can handle that just fine, but you're not dropping a Powerstroke in a Fusion (someone has probably done it).

[@FireLt2017]

I've heard it a million times: "Inline six engines are the best, that's why 18 wheelers use them". The inline 6 engine architecture has many features that make them well suited for 18 wheeler use. This does not mean the inline 6 is best for light duty trucks. So, for big trucks the advantages are mostly economic: fewer moving parts to fail, easily repaired in the chassis, more easily repaired and more inexpensive to repair than a V8 diesel for example. The low end torque is impressive, but limited to about 400rpm of peak torque output compared to the 1200rpm of peak torque output of a V8 diesel. It's no problem for big trucks with 10 to 18 gears. This is problematic for light trucks with inline 6 engines and six speed transmissions. Watch an IKE's gauntlet comparison, the V8 diesels out perform the inline 6 every time. Their broad range of peak torque output easily makes up for only having 6 gears. For the inline 6, the truck will get slower and slower until there is a gear that multiplies the torque enough to keep the engine from dropping out of its peak output range. It's usually a lower gear than the V8 diesels because their broader output range allows the truck to use a less critical, and usually higher gear to climb the grade. As a result, they climb the hill faster. Practically everything about the I6 is designed to cost trucking companies less money to operate and repair, and they are a more cost effective option for big trucks- that's been proven over time

[@Cauthon75]

In 1967 a friend of mine bought a Ford Mustang, and we all had fun about his cool new sports car. He had answers for our fooling around, saying that after many years of working in the family business of auto repair, he thought it was a mistake to use v-8's, with an extra head and more cylinders, more parts to fail or to need attention - as discussed in this video. If the engine needed work, he could take it apart and put it back together in one day. And as you said, a smaller engine at 8000RPM will not survive as long as one that runs 2000; every movement produces some wear, and it adds up.