Why Isn’t There A 7-Cylinder Engine?

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We have single cylinder engines, twins, triples, four-pots, inline fives, straight-sixes, but then we start to skip some steps. We jump to V8s, V10s and V12s, even V- or W16s. It’s a question many of you probably have never even thought to ask, but now that you’ve clicked on this video, let’s talk about it - why is there no such thing as a 7-cylinder engine?
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[@Drivetribe]

Thoughts on the sound of the inline-seven? 🤔Thanks to Bespoke Post for sponsoring today's video - New Bespoke Post subscribers get 20% off their first box of awesome - go to bespokepost.com/drivetribe20 and enter code DRIVETRIBE20 at checkout.

[@Matt_Deluca]

There's a youtuber called IceManV93 who simulated all the inline engine sounds from an inline 7 to a crazy inline 19. I think the 7 had the same firing order you showed here revving to 10k. He does a bunch of other weird engine configs as well.

[@jasonfisher8529]

Love the sound of an old-school V8 (I had a 1955 Dodge back in the day), but that simulated straight-7 sound was actually really cool. Even at speed, it's like you can tell the sound is coming from each piston moving independently / in sequence instead of in pairs. Pretty neat.

[@iseiyoulaitre]

I worked on a 7 cylinder engine. They were quite common in the late 20s early 30s. Mine was from a Cessna.

[@Iamthestig42069]

Kawasaki built a bike with an inline 7

[@siraff4461]

You brushed on it but I think its worth mentioning that most engines developed in the last half century or so have been based on pre-existing designs. That means it has been easier to simply take your inline 3/4/5/6 and double it up into a V 6/8/10/12. Infact most engines with more than five cylinders produced in the last few decades can trace parts to smaller siblings and indeed a lot share components. Dealing with the extra inbalance would be almost no work these days because it would tak ea computer about ten seconds to simulate it and spit out what to do to make it work. AS you rightly say though - why bother when you already have designs which don't need that extra work sitting there and able to cover any use case you might need?

[@Spidd124]

More educational content please, Mike has a great way of explaining it while posing a genuinely interesting question.

[@WaynesWorld69]

Absolutely. Hugely fascinating topic and I'm betting there are more topics that would suit.

[@WarriorsPhoto]

Agreed and I like his explanation of 7 cylinder engines.

[@HATECELL]

In radial engines odd numbers are generally preferred because then on the opposite side of a cylinder (a weakspot in the block) will be a particularly strong spot where the walls of two cylinders come together. And radials with even cylinder numbers, like 14 or 28 cylinders, often tend to be built like multiple odd-numbered radial "discs" behind each other

[@johnyoung1128]

Single row radial engines to the best of my knowledge always have an odd number of cylinders. If a radial engine has an even number of cylinders it will be a two or four row engine with two or four banks of an odd number of cylinders each. An example of a four row radials is the Pratt & Whitney R4360 with four rows of seven cylinders each for a total of 28 cylinders. For example the DC3 aircraft pictured had two engine types that could be chosen from during production, one was the Wright cyclone R1820 which was a single row 9 cylinder engine or the Pratt & Whitney “twin wasp” R1830 engine which is a two row 14 cylinder engine ( two rows of 7 cylinders ) the “R” indicates that it is a radial and the numbers following indicates swept volume in cubic inches. Radials are almost always air cooled and the perpendicular to the airflow configuration helps with cooling.

[@dennisford2000]

Generally same as steam lovomotives wheels

[@brianb-p6586]

That's not the reason for odd numbers of cylinders in radial engines at all. If you follow the firing order, only an odd number of cylinders results in an even (regular) firing order in a 4-stroke radial engine.

[@jayreiter268]

@@brianb-p6586 You are on the right track. The reason that a radial engine has an odd number of cylinders is the rotating cam ring valve actuating system. That is the simplest way to actuate the valves of a radial bank of cylinders. The geometry only works with an odd number of cylinders. Start your calculations with a 3 cylinder. It will run with a single lobe ring turning opposite to engine rotation at half speed. It also will run with a 2 lobe ring turning 1/4 speed in the same direction as engine rotation. The 9 cylinder I worked has a 4 lobe turning 1/8 speed opposite to engine rotation. A 9 will run with a 5 lobe turning 1/10 speed in the same direction as the engine. It is easier to draw for a 3 cylinder. Took me about 3 hours for me to understand. Once you see the principle it applies to the greater number of cylinders. It is nice to know but even in 1969 there were no radial questions on my A&P test.

[@Electrodancemonster]

When you're talking about Sisu Diesel engines you're incorrect. The engines they build are 3, 4, 6 and 7 cylinder engines with displacements of 3,3L for 3 cylinder engines, 4,4L/4,9L for 4 cylinder engines, 6,6L/7,4L/8,4L for 6 cylinder engines and 9,8L for 7 cylinder engines respectively. And every single one of those is turbo charged. They are indeed modular in the sense that they only use 3 and 4 cylinder heads which they then combine to make 6 or 7 cylinder engines. The new engine family they just launched is quite different though and they have a V12 engine that's no longer manufactured.

[@karvavarba2700]

Acgo power also provide 7 cyl diesel engines, dont know if theire misleading on purpose

[@Electrodancemonster]

@@karvavarba2700 Agco Power used to be Sisu Diesel. They did spell it wrong (ACGO) but they did mention it.

[@Electrodancemonster]

@@mcyclonegt towards the end of the video he mentions that a company called Agco already produces Sisu Diesel 7cyl engines. That's what we are talking about .

[@karvavarba2700]

Whatever the case, the title of the video is misleading.

[@brianb-p6586]

The graphic at 12:43 of AGCO engines clearly shows the turbochargers, which is either funny or sad.

[@ghenry85]

The inline 7 cylinder that he was talking about at the end was the 98AWF by Agco. It's used in grain combines.

[@tjroelsma]

One thing you forgot to mention with those massive ship engines is that they have a number of markings on the power setting lever. Some of those are more critical than others, but they all have one thing in common: you can run the engine(s) at that setting for only a very short time, as the vibrations will tear the engine apart and generally speaking it's better not to run the engine at those settings at all. You can actually feel it when a ferry ship is docking and at times during the docking procedure the engine(s) run(s) momentarily on one of those power settings, as the whole ferry starts to vibrate. You can imagine the severity of the vibrations needed to vibrate an entire ship.

[@cowboyhank456]

I always thought this had to do with it somehow reaching a resonant frequency, but this makes more sense. Didn't know that, very cool!

[@Kratsen]

I thought it was because of cavitation at the ships propeller due to rotating against the ships direction or something. Thanks for the info!

[@Kowalamaster]

8:37 I would only like to correct on one thing, super chargers and turbo chargers have been around just as long as adding more cylinders. 1905 for turbo chargers, and 1848 for super chargers forced induction has been around just as long as the internal combustion engine.

[@lgilles]

As long as humans have had fire we’ve been forcing air into it to make it burn hotter and more energetically.

[@dragan38765]

I love the educational type of content, would like to see more of it. I'm not really into the insane physics calculations and don't expect to see a 45 minute lecture calculating forces, but showing a quick final formula that is used like the one to calculate engine overlap is very nice.

[@ItsDaJax]

There were also straight 8's. Buick and Packard were known for their straight8's.

[@GeoStreber]

Also Duesenberg.

[@ItsDaJax]

@@GeoStreber Yep.

[@ChevyConQueso]

​@@GeoStreberDuesenberg, Bugatti, and Stutz were all the same engine design, but the Duesenberg was the largest in both physical size and displacement, followed by Bugatti as second largest, and Stutz 3rd, as the brands were priced. I got to check out a Stutz up close at my local machine shop that was being machined and rebuilt. It's always interesting what classic iron they have come in the door, but that one was a real treat. They're one long engine.

[@MrTripsJ]

Straight 8 sounds badass

[@Wormweed]

I was expecting this to be a long intro to why you are making a 7 cylinder car.

[@markembling]

Yes. Now that we know why it's a bad idea, I want to see it done anyway.

[@flameendcyborgguy883]

@@markembling ... Use Radial instead of inline. Radial 7's are white bread of radial engines and were used in cars before.

[@kiko9740]

Been wondering this for years now, always trust drive tribe to answer my dumb questions 😂

[@shebyjlo]

Totally

[@jasonfisher8529]

I always knew it was mostly a balance issue, but it was fascinating to see the actual math behind it along with useful visualizations. Drive Tribe doing Drive Tribe things, again.

[@danielssonsgarage]

​@@jasonfisher8529hate to say but 7cyl diesels is not uncommon. For example, agco power makes a 7cyl engine named 98HD for the tractor Challenger. Nohab from Sweden made 7cyl train engines

[@TheJpf79]

You've got the internet mate. Type in what you want to find out. You don't need to wait years for someone to make a youtube video to find things out.

[@kiko9740]

@@TheJpf79 it's more of a back of the mind thought. Never cared enough to look it up

[@grigorsamsa6564]

Also note that even though the straight 6 has its cylinders _moving_ as pairs, they are not _firing_ as pairs. A cylinder fires every 720 degrees of crankshaft rotation. Each member of a pair is 360 degrees out of phase with the other, which means you get six individual firings instead of three pairs. It's not just a doubled inline 3.

[@phsycresconquest6636]

In the graphic showing the i6 they do show this

[@tturi2]

a big bang i6 would be cool

[@TheSilverShadow17]

The straight 6 is also the most balanced engine in existence in terms of design. It doesn't need any balancing trickery like other layouts because it happens all on it's own. Each cylinder fires every 60° of crankshaft rotation and we know that 60° x 6 equals 360°

[@phsycresconquest6636]

@@TheSilverShadow17 a straight 8 is even more balanced by that logic. It’ll have a firing every 45 degrees by that metric making it more balanced. 360/8 = 45 However what actually makes an engine need balance trickery isn’t the number of cylinders per se but rather wether the total number is odd or even. An in-line 4 doesn’t need balancing trickery either because as one piston hits peak another is busy bottoming out. And it’s the same in a 6 cylinder as well.

[@Rover200Power]

​@phsycresconquest6636 why do so many 4 cylinder engines have balancing shafts then?

[@JackFromMorley]

I wonder if a VR7 would work any better? Still fairly pointless but it would sort the long crankshaft issue

[@irishwristwatch2487]

That'd sound great. Best of both worlds

[@flyingphoenix113]

I think it would be extremely difficult to balance, having three firings on one plane and four on the other. But, they did it with their VR5, so I don't see why it wouldn't be possible.

[@JackFromMorley]

@@flyingphoenix113 the existence of the VR5 is exactly what I was thinking with it

[@MrRandomcommentguy]

it would be possible but it would also be unnecessary as it would be easier to just use a V6 or V8.

[@Petrolhead66]

So why did someone come up with a 5 cylinder engine

[@davedarling4316]

Don't forget that the radial engines almost require an odd number of cylinders per bank in order for the firing order to work out in a simple way that's relatively easy to drive mechanically. They fire every other cylinder, and going around the whole engine twice will wind up firing every cylinder as long as it's an odd number.

[@ChargerMiles007]

I built and ran a FrankenBriggs 7 cylinder gasoline engine about 5 years ago (vids on my channel) It is made of individual single cylinder engine blocks with the cranks fastened together, and using a common ignition distributor and 2 carburators. It does indeed have its own unique sound, and ran very well. Cheers.

[@marksaddler]

Really like how this was explained clearly. Love the sound of my 5cyl, even if it is a diesel

[@jonathandemacedo158]

Alfa Romeo?

[@marksaddler]

@@jonathandemacedo158 nope, try again 😃

[@ryanwilliams6526]

Land Rover TD5, judging from the profile picture.

[@ghenry85]

Kubota has made a 5 cylinder for years.

[@Spudmuffinz]

Mercedes om617?

[@BLKBRDD]

This is a really well made video explaining this topic. Tbh I think a lot of people that have nerded out on exotic engine designs have thought about the idea of a 7 cylinder.

[@flameendcyborgguy883]

Radial 7's. They were quite comon in aviation in the 1920'ies, and were used for some trucks and odd cars. In general Radial engines are so overlooked that it hurts me, as they are beautiful and radial 7 is kinda the most common and boring type of them.

[@tonybaker55]

Having owned cars with both straight 5 and 6 engines, I found this fascinating. The straight six that I had was in a 2ltr Triumph Vitesse. That was a great car for a 21 year old to own! Sad to see it go, especially now, after so many years.

[@promerops]

I also had a Vitesse - lovely, fun car. I had the same engine in a 2500TC; also a BMW E39 523i. The point is - I love straight 6s and wish there were more of them still being made.

[@albinklein7680]

There are plenty of straight seven and straight nine Diesel engines out there. French manufacturers like Duvant and Japy made a lot of them for example. Deutz also makes inline 7 and V14 engines.

[@micah_boatwright]

2 of the best/reliable engines I've owned were both inline 6's

[@sixter4157]

Loved my inline 6 '69 Camaro.

[@soaringvulture]

I've owned a couple that meet that description: the Chrysler Slant Six and the Toyota 2JZ. Both of those were unbreakable and the 2JZ even had power.

[@jasonkeyes474]

This is a clear and concise means of explaining engine balancing. Thank you for helping an old car guy learn something about the very heart of his machine!

[@josephkelly4893]

One of your best videos in ages DriveTribe. Thanks for the thought provoking subject. Peace

[@UncleManuel]

And then there was Volkswagen in 1991 and developed the VR6. The idea was having a V6 but with a much smaller footprint. 15° cylinder angle and one head. BUT: the crazy part is that Lancia originally came up with that idea - in 1915. 😎🤟

[@pe8268]

I've though about this for many many years and eventually came to the conclusion that the main reasons probably are impracticality and diminishing returns. Seems like that was pretty spot on. Awesome video!

[@bazzaclarky7445]

Absolutely fascinating content this time around Mike. By far one of my favourite Drive Tribe videos! 👌

[@rotax636nut5]

I once had a 7 cylinder engine in my Rover but a new sparkplug turned it back into an 8..😉

[@ldnwholesale8552]

sually 3 or 4 spark plugs to turn it back into a 7.

[@paultreiber5597]

Sisu makes an inline 7 cylinder diesel engine for agricultural equipment.

[@TheActualJae]

Wow, great explanation, loved this vid! You should do a series on this sort of thing…

[@user-tn1vc1xz5d]

Lots of ship engines are 7 cylinder 😊. Many ship engines now can be isolated. One cylinder can be shut off for repairs while the others still run. Radial aircraft engines may have odd numbers partly to avoid harmonics.

[@winteronice]

Just made this comment myself, somebody beat me to it!

[@tyablo]

i was going to write the same. many aircraft radial engines have 7,9 and i think 11 cylinders too

[@johnyoung1128]

@@tyablo I haven’t heard of any 11 cylinder radials, usually if an aircraft engine manufacturer wants to up the cylinder count beyond 9 they will go to a two row design usually with 14 or 18 cylinders.

[@tyablo]

@@johnyoung1128 too lazy too google it?

[@samrodian919]

I liked that Mike! Well presented and visually very pleasing and easy to follow! Thank you.

[@dangreasley7934]

Brilliant, really enjoy the engineering videos. Keep them coming.

[@mwaynem]

So many variables! You shared some things I never thought about. Thanks for the incite into the complexities of cylinder layouts.

[@dlhennes]

One of your best videos in years. Informative, interesting, and down to earth.

[@johnpatel4687]

Thank you mate, great work done in explaining to the point. Easy to understand and no unnecessary talking.

[@markhann3628]

Love this style of video and would love to see more technical/engineering oriented content. You touched on radial engines, which makes me wonder: has there ever been an attempt to put a radial engine in a car or truck?

[@johnyoung1128]

Yes it has been tried as custom projects but they don’t make much sense for cars because of the vertical space radials need. Production aircraft radials are virtually all air cooled so a cooling fan would likely be needed. Some WW2 tanks used adapted aircraft radial engines more out of wartime production reasons rather than any specific advantages of this engine type for this application.

[@Dutchdriftking]

Now I need someone to build a VR7 engine. The VR5 engine exists and works beautifully. Its just a VR6 with one cilinder less. If you take have Veyron engine and cut one cilinder of you have i. Although a VR8 would also be epic. 😊

[@Sainty-0]

Love this engineering content. Really, really interesting. More of this please.

[@mercy_studio]

I've had several 7 cylinder engines in my cars. Although to be fair, they started out as 8 cylinder engines 🤕

[@mikem9536]

Ford was famous for their 7 cylinder v-8's, ensuring that your 10 MPG truck only got about 7 MPG.

[@josheigenberg]

Quick correction on the AGCO engine as someone who uses a tractor with it. Each cylinder does not have its own head, and it appears that they use an inline 3 head and an inline 4 head. Also, your comment at 12:40 about them being naturally aspirated is incorrect as basically no modern diesels in the 10 liter range are, and the AGCO has a compound turbo setup making about 40 psi on the monitor. The in-line 7 9.8 liter is governed to 2300 rpm, and makes 431 hp @ 1700, and 1,417 lb-ft @ 1500.

[@LtNduati]

8:00 It maybe a synthesized engine note, but I want a car that makes that sound

[@benjaminburger7214]

Thank you. I found this very interesting. Something you might want to look up is when a yamaha team in the UK built what was called the pig engine. Basicly what the wanted to do was to compete with the V twinn Ducati's of the day in the sense that they had better grip due to far less firing/power pulses throug the drive train and rear wheel resulting in better grip. They did this by simultaneously firering cylinders 1&4 and 2&3. I suspect that firering 1&3 and 2&4 wold result in fat less tortional flex of the crank shaft, but would have ment the had to completely replace the crank. To the best of my knowledge this would have been against the rules. Thus valve, injection and ignition timing was all they had to work with. Another very cool engine was the 2T 115deg V5 that Honda used in the GP500. Those were the days. Keep it coming. Love the content.

[@309gti8]

I knew 7 cylinder radial engines existed but I was completely unaware that an Inline 7 was a thing! I’ve always wondered why we didn’t have them in cars, but didn’t know they did exist in other applications.

[@richardroberts8742]

In-line 9 cylinder engine is like butter though! Worked on many different engines with different cylinder configurations including inline 7 which has a slightly odd sound, 9 is the best in line though, even over a 6.

[@1959Edsel]

I've seen one of those AGCO straight-seven engines set up as a stationary power source. It fills a niche where a straight six wouldn't be enough and a V engine wouldn't fit. Besides its interesting exhaust note, the AGCO engine can shut off fuel to individual cylinders when there's only a partial load.

[@ADMSvare]

This may be one of the best videos you've done, mate. My first car, a 1965 Ford Galaxie, had a 240 ci (3.9 l) straight six in it. That engine was one of the best ever, I just didn't appreciate it at the time. It was the fourth generation inline six that Ford made, and stayed in production until 1996.

[@rainbowwarrior2635]

I did see a inline 7 diesel once.. I was in new hampshire and there was this snow plow machine, one of those tracked machines you use to smooth the snow at ski resorts, with the plow in the front and the rakes at the rear and it had in inline 7 turbodiesel. It was some strange scandanavian design. And there are slow speed inline 7 diesels used in ships.

[@dieselmats]

Was it the engine or the machine that was strange scandinavian design ? The Agco 7 cylinder is made in Finland. Was it a Snow groomer ?

[@rainbowwarrior2635]

It was a snow groomer but this was back 1999. The engine was a strange design, I'm surenthe snow groomer was also a strange design, it was not from anywhere around here.@@dieselmats

[@Maserati7200]

7 being my favorite number, I’ve always wondered this as well! I will eventually get a car with a 7 speed manual (Porsche, C7 Corvette)

[@MrCarrera28]

I hope I am not in the minority but I really find these educational videos highly informative and most enjoyable and if they get you the appropriate views I hope you keep can keep rolling them out.

[@ShinzoHossa]

Amazing. I just learned something useful on the internet. Way to go DriveTribe!

[@GRW3]

There are plenty of 7-cylinder engines, they just happen to be for airplanes, in the form of radial engines. All radial engines have an odd number of cylinders, 3-5-7-9, with 7 and 9 being the most common.

[@flameendcyborgguy883]

Thank you, I though I was the only one who remembered beauties that are radial engines.

[@sideshowbobcbr]

I love this type of vid. It's what got me into Drivetribe in the first place (have loved all the content since, don't get me wrong!) It does make me wish I'd studied automotive engineering though!!!

[@fosterfuchs]

Thank you for presenting this in a way that someone like me can follow. I'm not a petrolhead, but I'm interested in the topic.

[@lorditsprobingtime6668]

Oh darnit! I thought I had you when I read the title, knowing there's 7 cylinder radials used in some light aircraft but, you had them covered too. I am a little confused by the fact all radials are odd numbers of cylinders though, that's something I'll probably never comprehend. Incidentally, my car is a Nissan Pathfinder and it's got their 3.5 litre V6 and that engine is literally one you could balance a coin on it's edge on. I have had many old carburetored straight sixes but none have ever run near as smooth as this thing. Admittedly fuel injection probably helps but I'm guessing there's a lot of counterweighting and balance shafts doing all sorts of magic trickery but, it really is surprisingly smooth at idle.

[@mikem9536]

60 degree v-6's run a lot smoother than 90 degree v6's.

[@lorditsprobingtime6668]

@@mikem9536 I honestly don't know but, it's so smooth I guess it would be. Apparently it's the same V6 they used in their popular 350Z sports car. I've had numerous straight sixes, a couple of 4s and several V8s and love the feel and sound of a V8 but, none have been remotely as smooth running as this V6.

[@wills.5762]

Not all radials have an odd number of cylinders. Lots of 14 and 18 cylinder radials. Even 28 cylinder radials.

[@lorditsprobingtime6668]

@@wills.5762 And, the 18 cylinder ones are TWO 9 cylinder radials jammed together, same with the 14 cylinders except using 7 cylinder engines. Same thing, still banks of odd numbers of cylinders.

[@docternoblex]

6:15 my dad had an Audi 4000 with an inline 5, it was the smoothest car engine I have ever heard, smoother than any inline 6

[@identiticrisis]

in terms of the smoothness of the crank rotation in response to the start-stop motion of the pistons, inline 5s are indeed _far_ smoother than inline 6s.

[@ecksray48]

Imagine if Audi and BMW revamped their lineups so that the model designation indicated the number of cylinders (3 series = 3 cyl, A7 = 7 cyl)

[@darwinskeeper421]

Dang, here I was going to remind you about the Warner Scarab aircraft radial engines, which were among the smaller radials produced during the interwar period.

[@Ensign_Cthulhu]

In fact, all radial engines are odd-numbered, and the ones that aren't are composed of multiple odd-numbered banks stacked in a row behind each other (e.g. "18-cylinder two-row radial engine".

[@svdlaan]

No doubt Allen Millyard could make one in his shed from old Kawasaki engine blocks and it would run beautifully!

[@mjallenuk]

Outstanding explanation ... more of this please folks

[@guym2170]

Loving the educational content, so interesting!

Very intersting topic and nicely done Video. Thx

[@G2Merica]

I had a Subaru Justy(3 cylinder) as soon as I added power(intake, exhaust, tune) and it drastically shortened the life of my crank shaft. Boom

[@steveballmersbaldspot2.095]

I'm guessing it didn't come with a forged crankshaft from the factory?

[@_..-.._..-.._]

Look up simulations of how an i7 would sound, they’re the creepiest coolest sounding thing I’ve ever heard, like a v8 and i5 made a baby. They’re wicked.

[@SHOdown13]

Very informative. Often po dered this exact question. You should follow it up with a story on the best Straight 6 from around the globe.

[@slartibartfast2649]

11:13 an inline 8 is not two inline 4s joined together, since an inline 4 usually has pistons 1 & 4 and 2 & 3 moving together. The animation shows it with opposite cylinders moving together.

[@identiticrisis]

Some early ones were, e.g. Bugatti

[@brianb-p6586]

The animation shows a rational inline-8. Two inline-4's in the same phase end-to-end would be nonsensical, although two inline-4's 90 degrees out of phase end-to-end would work.

[@slartibartfast2649]

@@brianb-p6586 Regardless of how the firing order is in real engines (Buick, Alfa etc.), the voiceover says it is two straight 4s joined together, and the animation shows something different.

[@jujitsujew23]

Very cool sound that seems worth doing

[@magellanicspaceclouds]

I've been wondering about this. Thanks!

[@AndyMyers]

One of the best videos I've seen on this channel; I gained knowledge.

[@Schlierfy1]

Loved the genius of the Opposed piston engine the US Navy uses. Always wondered why cars/ trucks don't use opposed piston engines.

[@ldnwholesale8552]

They did,, knocker Commers. One of the worlds most hatefull engines.

[@davewebster5120]

you can totally do a 7-cylinder engine. My brother built a functioning one out of legos. It's an inline-3 spaced out with a v2 between the inline cylinders. 1, 2, 1, 2, 1. A straight 7 may be a bad idea, but the staggered 7 is easily achievable with current technology.

[@ghenry85]

Agco has a inline 7 for combines(look up Gleaner S98 combine specs).

[@benoitdeclercq9722]

always nice to learn a thing or 2! nice vid!

[@solocamo3654]

Packaging and balancing. Edit: glad you covered it immediately.

[@john1703]

So, if you can fit it under the bonnet/hood, the best balance for the fewest cylinders is a straight 6. No wonder most trucks use them. Conceptually, put a mirror after the third cylinder and you will "see" the other three in the mirror.

[@mikehipperson]

Many years ago there was a car dealer in East London who 'specialised' in yank barges. The oldest one he had was a 1925 Studebaker President that had a straight 12 engine. Never heard it run but he was trying to offload it for £250!

[@jbj27406]

Seven cylinders is one of the most common setups for radial engines. In fact, all radial engines have odd numbers of cylinders.

[@patrickporter6536]

Per row.

[@jbj27406]

@@patrickporter6536 Correct.

[@copiousroy]

Interesting and informative video thanks Mike

[@henktankxd]

the agco power 98hd is a 7 cil diesel used in some big agricultrel machines

[@svenforfifr1390]

Y'all should really give Angethegreat some credit fir their engine simulator and its sounds if you're gonna use it.

[@54mgtf22]

Hey Mike. Love your work 👍

[@michaelmaher1628]

Definitely more videos like this please.

[@Woodn509]

all makes perfect sense, the flywheels purpose being to carry the engine through the idle strokes, I wondered for many years about Rolls Royce Merlin / Meteor, no flywheel, enough compression strokes, so close to each other that it carries itself

[@johnyoung1128]

The propeller rotating mass acts as a flywheel in aircraft applications.

[@Woodn509]

@@johnyoung1128 I get it in aircraft applications, but in a tank, well the clutch is a bit of a beast!!

[@mr.monitor.]

What makes the old 6 cycl in-line Cat engines so smooth?

[@justincork3838]

I do enjoy my Volvo’s odd 5 cylinder diesel noise quite satisfying

[@jc1982discovery]

Could you imagine what a F1 7cyl would sound like😮 suit you sir 😂👍

[@AnonymousCaveman]

I love how cyberpunk/hyper futuristic a 7 cylinder engine sounds.

[@flameendcyborgguy883]

Radial 7. As I already kinda stated over many different comments, THE MOST popular of radial engines, used in cars already... In the 1920'ies...

[@AnonymousCaveman]

@@flameendcyborgguy883 ok

[@xevan_knight_official]

I always wondered about a straight 7. I also wondered about a V4 and VR4 engine, a VR5 and VR7 engine and also W14 engine instead of a W16

[@firstnamesecondname5341]

Mikes finally finding his platform 👌.. for sometime there seemed to be a sense the big three looked on him as a less than an equal presenter.. but not now. Great video 🫡

[@cerneysmallengines]

To make a complex answer simple, derivatives of 360 are the reason why. When you degree a crank or cam shaft, it helps to work in the 360' notions that we use. Here are some common fraction uses of 360 1/360 or 360' 2/360 or 180' 3/360 or 120' 4/360 or 90' 5/360 or 72' 6/360 or 60' 7/360 has the first decimal degree of 51.428571 repeating. 8/360 or 45' 9/360 or 40', however, 9 can also be broken into 3, kinda like how you see inline 6 cylinder engines only having 3 camshaft degree positions, essentially making it 2x 3 cylinder engines or in the 9 cylinder, 3x 3cylinder engines. this describes a lot about the problem with certain engine combinations. While you could make a 7 cylinder engine, it would be out of balance or to make it in balance would be next to impossible.

[@Jagggggg88]

That racing XJ looks so cool 👌

[@Nedw]

Panhard, before its final demise under Citroën, was working on a radial car engine. But it's very difficult to find info on it. Maybe a video on Panhard would ve nice? Definitely one of the weirdest - and at the same time most revered - car manufacturers.

[@GrOuNdZeRo7777]

I've wondered this point, but I'd still want one! Especially now someone simulated the sound! 😢

[@wallcouldtalk]

Uhhh, there IS an inline 7. They're giant diesel engines generally used in marine applications.

[@daveunknown01]

You didnt finish watching the video😵‍💫

[@wallcouldtalk]

​@@daveunknown01I haven't. I'm just getting to that section. Click baity title riled me up.

[@brianb-p6586]

The "counterweight" mentioned at 14:23 is actually the flywheel, which is not a counterweight at all.

[@stagesmith]

The Audi 5000S had a 5 cylinder engine, a V-4 with an inline 1

[@deaks25]

I'm always up for 15 mins of engineering geek-out.

[@localsheriff]

There were even I8s made by Olds, Buick, Pontiac and Packard and the last three stuck with those way into the early 50s. While those were indeed torquey for its day they clearly showed their disadvantages in car use : a long crank that doesn't like high revs + packaging. A 7cyl is simply not sensible for car use since an I6/V6 can be built to do the same job at same displacement or as a V8 which is a much sturdier and rev-friendly more compact package. Since both inline and radial 7cyl can be ruled out of car use due to packaging, we're left with either VR7 or multibank alternatives and those come with their own limitations and unnecessary complexity compared to I6, V6 or V8 alternatives that make a lot more sense. I'm pretty sure some exotic car company could possibly develop a 7cyl for car use just to prove to their limited audience that they CAN, however it would be unnecessarily complex, expensive and impractical for use in regular high-volume car production

[@Braskus]

The applications mentioned for inline 7 and 8 cylinders engine also operate at much lower RPM's. Back when strait 8's were used in cars they would often only revv to 4,000rpm or something. That was the case for most at the time i guess. But once you start increasing the RPM the downsides start to show them selves more. Like pushrods.. Which for some reason are still being used!

[@IndridCool54]

Here in the US straight eight cylinder engines were extremely common before the mid 1950’s. Never thought about a seven cylinder! Cool! 👍🏼

[@mikem9536]

I want to make a tiny inline 7 engine now :)

[@IndridCool54]

@@mikem9536 imagine the sound of that! 👍🏼

[@brianb-p6586]

The timing of the inline-8 shown at 11:17 makes sense... but note that it is certainly not the same as two inline-4's connected end-to-end.

[@ThomasNavarroR]

Now because of that simulation, i would love to have one 7Cylinder :(