Flat Plane Crankshafts

[@lklk3384]

Great explanation, and NO robo-voice!!!

[@wymple09]

Yes

[@paulcochran2212]

whats so bad about an automated voice

[@RizLazey]

@@paulcochran2212 that's usually means those robo voiced bitches doesn't know that they're talking about and pretty much lack of research

[@SadFroge]

@@paulcochran2212 it is just really annoying to hear in my opinion

[@labounti]

Pretty close tho

[@frostyab7579]

The flat plane crank that is pictured is only used by Ford. It is used because this form is an intermediate step in manufacture of crossplane crank. Ferrari and other european sports cars use different form where the middle two throws are in the same direction and the outer throws are in the opposite direction. Ford crank is 0, 180, 0, 180; Ferrari crank is 0, 180, 180, 0.

[@drtone]

Or used to gain some benefits, and reduce the drawbacks in the engine that size. So, its a half engineering attempt to do flat plane crank, and therefore yields compromised benefits as ascribed to the so called flat plane crank. In particular, does not produce the sweet sound of the classic full flat plane crank. Its a half flat plane crank. I Like the rumble of old cross V8's, and the scream of full flat plane. Ford GT350 sounds mediocre. Carbs sound best, lol.

[@testy462]

You are insane if you think the GT350 sounds "mediocre". Far and wide its been lauded for it's exhaust note. It doesn't sound like a small displacement V8 Ferrari but it isn't a small displacement V8... Scroll up and type "GT350" in the search bar... the first suggestion is "gt350 exhaust" for a reason lol.

[@bobanppvc]

@@testy462 i think it is used by Maserati Granturismo too

[@immikeurnot]

@@bobanppvc Maserati engines are crossplane.

[@marshalcraft]

Well both 0,180,0,180 and 0,180,180,0 are provably flat plane cranks, so... you must be talking about firing order which is obviously a different thing.

[@Tomazack]

I have been a car enthusiast for around 15 years, but haven't really done my research on V8 engines, and why some of them sound so different from others. Thanks for an awesome explanation, I learned something I am ashamed to have been ignorant of for years. Thanks for a great video.

[@mattfairfield9103]

I’ve literally been wondering how a flat plane crank works the past few weeks and every time I get on KZbin, I’ve forgotten to look it up. Then this video comes up. Thanks man :)

[@ipcheck]

This is by far the best video I have ever watched that explains something needed to be explained. Wow. 🙏🏻

[@Double_A_Ron]

Incredible video!!! The merging traffic with the JACKASS analogy almost got my coffee spit all over my laptop!

[@Michael_00001]

Be honest, you weren't really drinking coffee and that overused analogy just never gets old for you. It's ok. I used to always say that too even though I wasn't drinking a damn thing.

[@Double_A_Ron]

@@Michael_00001 that was 2 years ago...... I don't remember lol. I do love coffee and drink it, so I probably was. 🤷🏻‍♂️

[@Michael_00001]

@@Double_A_Ron I'll accept that 😄

[@gitedun4716]

Best video out of the options given when searching for difference between cross and flat plane crank. Very easy to understand if you have no idea of the concept. Thank you.

[@tylerlooney8058]

Love how we are just now starting to see that our old tech is better when combined with our modern tech instead of relying on our modern tech alone.

[@177SCmaro]

crossover headers also solve the issue of exhaust pulse overlap in cross plane v8s. it also makes them sound like their flat plane counterparts.

[@bacchusthompson5834]

@Kay Kay the exact technology used by all 2-stroke Performance Exhaust Co.'s

[@deanhilbig8606]

YES! 180° headers have a sound like NO other! Almost shrill! Peace bro, here's to Tune Deafness!

[@177SCmaro]

@tchrisman625 kzbin.info/www/bejne/d4rVpYOmYrSokNksi=pyVuORPX3-yMzOzR First one wasn't right, I didn't realize it was a flat plane but the second link are cross plane v8's that sound like flat planes plus he explains why.

[@harvijaysinhgraj5917]

This is the BEST VIDEO on KZbin for this topic.

[@johndouglass3691]

This video was an outstanding informative and concise demonstration of the flat plane crank. Exactly what I was looking for. Great job!

[@rand49er]

Excellent graphics used here to help picture and describe these two approaches to V8 crankshaft design. Thanks!

[@gumballer133]

Best description I have seen. Having 2 cars with Flat Plane cranks, and one Cross Plane, I never quite understood the difference until now.

[@Snowcrest289]

Hold yer' horses!..........Benefit #4 (sound quality) is still open to debate. Smooth Flat-Planes sound cool, but growling Cross-Planes sound cool too!

[@northtexasskies3243]

Snowcrest the Yamaha r1 sounds amazing

[@willvanallsburg4703]

never heard austin racing 2015 r1 i guess

[@hotroddaddy-et4xg]

debate for sure..i love the sounds of my cross plane crank big v-8 big set of header and 3" pipes to let it out can't be beaten. flat plane sounds great though.

[@EdgyNumber1]

Snowcrest Agree: secondly sound can be tuned to create the desired effect. Traditionally, flat plane V8s have usually always sounded like two inline-4s. Interestingly it is possible to get a crossplane inline-4 to sound like a small V8. A Flat 4 has a totally different sound characteristic to either but the exhaust headers and firing order can be changed to give a different sound more similar to an inline-4. Believe it or not, there's a whole branch of automotive engineering devoted to just this subject...

[@MrSandwichk]

R1 and V4 panigale sound bad.

[@madmat2001]

You can somewhat get around the uneven firing effect on the exhaust of a cross plane V8 by using tri Y headers. Instead of dumping all the pipes into a common collector, you split them up into pairs based on where they fire in the order and then tie the two pairs together. It makes a pretty remarkable difference.

[@msengineeringdavid3702]

'' you can some what'' That's still a no bub.

[@mattc.7411]

@@msengineeringdavid3702 pretty remarkable difference though

[@albertgarcia7091]

It’s not somewhat, it’s actually done and works

[@Johnny-tq9no]

@@msengineeringdavid3702 individual pipes will

[@xxxYYZxxx]

It's worth nothing that dragsters with straight-cut pipes have ZERO issues with uneven firing.

[@theLEGOguy22]

Great explanation. I’m new to understating these mechanics. Recently purchased an Alfa Romeo Giulia which has a flat plane crank V6 at 90 degrees. I found your video very informative.

[@bloodspartan300]

Its not possible to have a flat plane v6.

[@brianb-p6586]

The Giulia has a V6 variant of the Ferrari F154 engine family. F154 V8's have flat-plane cranks, but a flat-plane crank in the V6 would produce a very uneven firing order. The Giulia V6 has, as expected for any 90 degree V6, three throws in separate planes. A 90 degree V6 usually has split crankpins for compensate for the vee angle being 90 degrees instead of the 60 degrees that it should be, but the photos that I found of this crank show that it does not... causing mildly uneven firing which results in a characteristic sound that some might guess (incorrectly) is due to a flat-plane crankshaft. There is a somewhat common belief that the Giulia V6 has a flat-plane crank, but that is contradicted by actual photos of the crankshaft, and probably results from an invalid and nonsensical assumption that since the V8 engines of the same family have a flat-plane crankshaft then the V6 would as well.

[@Ianochez]

the european flatplane is easy recognizable, the two middle up and the sides down, that are in fact nearly the "same" form has the inline 4 crankshaft. All the info is still accurate in my opinion. but if you want me to consider you has a subscriber, don't hesitate to make reference of all the possible configuration, these twos with their firing orders are only two possibilities. If you talk about a manufacturers configuration, you have to mention that others exists and are not pictured. It is a great video, that kind of I love, easy to watch, easy to appreciate. the format is really good. I don't know how long it takes to make thoses 3d animation, I love them. if there are the only twos you want to make, you mention that other kind still exist and thoses are not the only ones that exist. thank you for you reading, you make great content.

[@suserman7775]

Well, I think BOTH the cross-plane and flat-plane V8s sound AWESOME.

[@stephenmikell2057]

Very nice explanation. Informative, mature, and professional.

[@jimmykelligan9252]

8ŕõrõo::opróóçcdččćvcčć'ćć'

[@Brotherkiller17]

Really liked this, and the insight about the flatplane crank and the crossplane crank.

[@DomoNismo]

Simply but also well explained and very informative, thx for a great vid! Particulary I liked the explanation with the zipper efect!

[@ducfandan1117]

Decent explanation, but missed on a couple points. For exhaust pulses, timing the pulses for proper scavenging can also be done on a crossplane... you have to do the math on header tube lengths to get them lined up properly. It’s rarely done (exhaust fabricators seem to be allergic to math), but every now and again you find custom headers on a crossplane that sound like a flat plane. Also, the Mustang doesn’t sound like a Ferrari V8 for the inverse reason... it has unequal length headers, resulting in a subtle lilting/surging sound akin to a normal “American” V8. So pulses and scavenging has everything to do with exhaust system design, with cross vs flat plane firing order just dictating the tube lengths to achieve the desired results. For an example of how header design can change the sound and scavenging, look up “180 degree headers” for typical American V8s (the SBC or LS, for example). Secondly: tuning/cylinder optimization. No explanation is given for *why* a crossplane would have low performing cylinders. Reality is, every poly-cylindered engine has some inequality in combustion. The more modern your engine management system, the better you can account for this. Some engines are literally tuned per cylinder. That was the whole point of using Webers on race cars... the ability to tune the mixture for each cylinder. Now with multi port or direct EFI, individual coil packs, and sensors galore, some engines can have fuel and ignition tuned independently. This will reach its zenith with the Freevalve technology, which will allow infinitely variable valve tuning for each cylinder as well. There is no fundamental reason a crossplane is somehow less able to be equalized than a flat plane.

[@JViello]

DucFanDan That's not the only reason. The flat plane Ford sounds different because the crank journals are staggered every other. --_--_ vs --__-- where the center two are on the same.

[@alankulchecki3160]

Ducfandan, AGREED, I had a set of tuned 360 headers on my big block ford. and they work, but what a nightmare to install...

[@_entrxpy]

Exactly the comment I was searching for, you literally took the words out of my mouth. 👏🏻👏🏻👏🏻👏🏻

[@zenden6564]

Awesome follow on explanation - thanks!

[@Skytrooper82d]

Thank you..

[@stankygeorge]

Thanks for the explanation! I enjoy the sound of flat plane cranks in sport cars and the sound of cross cranks in sedans, pick ups etc!

[@sciroccoR]

this was a very well made, understandable and smooth video. nice job!

[@MrNismopro]

This is the best explanation of the differences on KZbin. 👍🏼Well done.

[@Eat_Yo_Dam_Beans]

Great video, very educational and simple to understand. Cant wait to watch the rest of them! 👍

[@4406bbldb]

I did some work with Petty back in the early 70s. I like your video. Ours flat crank was so wild it wouldn't run below 3,000 rpm without breaking something. Or 366 cid hemi w/4bbl made almost 900 HP and it wasn't even really tuned yet. It was dropped because it could only be driven at speed . Good memories.

[@grahamparsons1070]

Perfect thank you! I only just finished watching that episode of Jay and was going hunting for a video on flat plane cranks. Nicely done 👍

[@nealbradleigh5069]

THANK YOU FOR this informative video! I'm too ashamed to let guys in my inner circle know my technical ignorance, sooo videos like this help fill in the missing "tech-nese" to keeps us (read lots of adult men) looking savvy among peers!

[@videomaniac108]

Thanks for the interesting and informative discussion about different types of V-8 crankshafts. I've been an ardent gearhead since I was a little kid and I wondered about an arrangement as described below for an engine design when I was a kid, designing my fantasy engines: I was wondering about a variation of the flat-plane crankshaft, where the number three throw is lined-up with the number two throw, 0º crankshaft offset. Consider the engine as being a V-8 with two inline 4-cylinder banks 90º apart, numbered 1-3-5-7 on the left bank and 2-4-6-8 on the right bank, as viewed from behind by the driver. With two connecting rods on each crankshaft throw, here is the firing order: 1-2-5-6-7-8-3-4. On each bank, the cylinders are equally spaced at 180º and so the exhaust pulses would be evenly staggered for good scavenging. My thinking at the time in doing this is that it might be easier and cheaper to construct than the flat-plane shown here. I suppose that the same second harmonic vibrations would also occur in my design, although they might partially cancel each other out or offer irregularly spaced vibration pulses over the full 720º cycle.

[@leeselset5751]

One of the biggest intangible benefits of the cross-plane crank V-8 is the aggressive, muscular sound. The source was revealed to me when I listened to a video showcasing the different I-4 engine sounds. The cross-plane 4-cylinder sounded weaker than, but just as aggressive as a traditional American V-8. So yeah, I'll stick with my cheap but effective and reliable American V-8s. At the same time, I am glad this sort of thing is getting attention, because that attention, combined with a healthy level of debate, is likely to spawn advancements in BOTH technologies.

[@michaelhartzell9758]

The more you watch these videos the more you learn. Thanks and thanks UTUBE

[@grantmills4184]

Excellent video, very concise and informative

[@yellowhammer4747]

EXCELLENT EXPLANATION SIR. THANK YOU FOR THE EDUCATION!

[@marnixinho]

The ''Flat plane crank'' you showed is exclusively used in de Shelby GT350, all others are mirror images just as 99% of inline 4 crankshafts. Also, a flatplane crankshaft V8 still fires every 90 degrees thanks to it's 90 degree bank angle instead of 180 degrees like you said.

[@jamesbosworth4191]

Yup, if it fired 180 degrees, it would be running as if it was a jumbo-sized 4 cylinder.

[@bencezavarko7312]

Whoa there! Better sound? That's pretty relative. I like both but the crossplane is my winner

[@thibaultfrancois8013]

You definitely need to do more videos. I personally love them and wish I could see more of them!

[@naysaykiller928]

Cross plane 8 cylinders have a soft spot in my heart tho. The sound is one of a kind.

[@Bman310]

This was a superb video! Teaching is its own skill, and you have it, my friend! Great visuals, pacing, and analogies... Not sure how you made those amazing animations but I’m a subscriber now so I look forward to your other videos: thanks!

[@jakewestin4176]

Absolutely OUTSTANDING video

[@johnjessrock3764]

Fantastic video. Thanks for putting the time into producing it.

[@ROFLWOFFL]

This was totally informative. Thank you very much!

[@signature11.81]

I appreciate the work youve done in this video

[@danhillman4523]

I wondered why Euro V-8 engines sounded different, now I know. Thanks.

[@eightfivezerobraxton5509]

better explanation than engineering explained, I like the animations you did

[@armandoboensel593]

Dude you made that so simple to understand.... thanks

[@salzer211]

Great explanation! Easy to understand. Thanks!

[@badad0166]

Concise information delivered in a professional manner. Most satisfying Utube experience. Harumph.

[@hotdogy12345]

Great way of explaining it!! 2:13 caught me off guard LOL

[@skyraider87]

You'll never ruin cross planes for me! They sound better.

[@Csirkefoga]

Finally understood the difference and significance!! Thx, great vid.

[@jameskerr2812]

I have one of these in my GT350, love it! Great video, too!!! I laughed at 2:15.

[@grabir01]

With tuned exhaust, the pulses can be timed and corrected with the dual plane crank.

[@ssimon64]

Exactly

[@jacknickolstine3355]

It is essentially just an air pump

[@VideoKimT]

Very well explained, thanks!

[@johndouglas4528]

Excellent discussion and video.

[@ShelbyCorGT500]

Best explanation ever !!! Thanks 🙏

[@CrazyBear65]

It all boils down to the individual application. What are you trying to accomplish? Are you running a work truck? Are you running a race car? Are you running a four cylinder front wheel drive shitbox? What kind of performance are you trying to get out of your engine?

[@BlitzkriegRap]

Very informative and well explained video. Great job!!

[@TheRowdyJ]

a 180 degree header fixes the problem of the incorrect scavanging pulses. makes a sb v8 sound like a ferrari

[@TheRowdyJ]

@@SchafdoggGTO im in it for performance. chrome and sound doesnt get you down the track any faster.

[@CrazyBear65]

@@SchafdoggGTO - I want the sound of a Big Block, myself.

[@CrazyBear65]

Chrome don't git ya home, so they say, but you sure look fuckin cool sitting there broke down on the side of the highway. But nothing else sounds as sweet as a big American v-8 screaming seven grand.

[@MrTheHillfolk]

@@CrazyBear65 No doubt ,but the vw W8 sounds pretty nice. Too bad it's wicked expensive and doesn't have much aftermarket support like the VR6 does. Slap a turbo on one(VR6) and Grandma could run a 10. kzbin.info/www/bejne/b56nmaeJjrGFr6c

[@randymarsh5088]

MrHillfolk you my friend have impeccable taste .

[@NakariShiro]

The P60B40 4.0L V8 from the BMW M3 GTR used the flatplane crankshaft for both the road version and their LeMans racecar. That thing paired with straightcut gearbox sounds just so godly 🤤

[@rhedinrage1601]

Thank you this was really helpful to my studies

[@pebblesbambamtwins]

Thanks for the vid and explanation! I love the sound of my GT350!

[@mattbrown1114]

Chris Great explanation. Thanks!

[@Inazuma68]

Thx - very cool explanation. Now I know how it really works

[@Lefty16jd]

Great video like the explanation and the visuals

[@duncanj206]

Great video thank you for your time making it 🎉

[@GearsNCarpentry]

Loved the traffic analogy

[@sauluribe7082]

Good job in explanation and illustrations

[@Slaktrax]

Great explanation and an informative video. Thank you :-) Though flat plane crank V8's (for me) will never sound as good as a cross-plane crank V8. They sound very much like a plain ol' four cylinder twin cam engine. I'll take the beautiful V8 rumble any day and pass on the efficient scavenging and high rpm ability. The whole idea for many that understand, is the great torque a decent sized V8 can make right there from idle and maintains great torque throughout a realistic and usable rpm range (

[@michaelbenardo5695]

Flat-plane V8s run like a pair of 4 cylinders sharing a common crankshaft. That's why they sound 4 cylinderish. They also, at certain RPM/Load conditions, vibrate like a 4 cylinder as well.

[@Slaktrax]

@@michaelbenardo5695 Agree, they don't float my boat either.

[@jetstream01]

Great video. If you're not aware, the sound an engine makes is determined almost entirely by the number of cylinders and the firing order. Motorcycles I think are the best example of the different engine sounds. Listen to a traditional inline 4 bike like a CBR and notice how different it sounds from a crossplane inline 4 bike like the newer R1s. And also notice how a crossplane 4 cylinder sounds very very similar to a crossplane v8. And also a triple cylinder like a Triumph sounds very similar to a V6 or V12.

[@brianb-p6586]

It is also determined by the exhaust system. Engine configurations which make equal-length exhaust runners with proper timing impossible (such as cross-plane V8's and boxer 4's) lead to characteristic sounds (which some people like, and others do not).

[@jetstream01]

@@brianb-p6586 yes- great point. The difference in sound between a WRX with UEL headers vs EL headers is pretty significant.

[@waynep343]

If a cross plane V8 crank is fully counterweighted the end counterweights can be much lighter then the conventional and counterweighted crank allowing faster acceleration with less Mass. The only issue is you have to design the crank to match the rod and piston weights. This fully weighted option also gets rid of the whipping effect that rips the guts out of engine blocks at the harmonic frequently speeds

[@jamesbosworth4191]

I think the Ford Y block and the same era Lincoln engines had fully counterweighted cranks, and the Y block had an unbreakable bottom end. I guess that's why.

[@iwens1966]

I guess growing up in the US, one becomes used to the cross plate variety. I love the sound of a cross plane with long tube headers and a hot cam. The Mustang does sound good, along with the Ferrari, but, yeh.......a well tuned LS1 is pure magic.

[@ricardorodriguez7590]

Very well explained. Great Job!

[@glenndjubilee]

Thank you. I was going to look this topic up today and now I don't have to!

[@scottwelchsdsol]

Awesome video, hope they keep coming

[@ricardoespiritu8843]

Thanks for explaining this so clearly, do you think that a 4 cylinder with a cross plane crankshaft would work? Like in a passenger car.

[@steveelco114]

well explained

[@colinellipses3536]

Excellent video. Well done! It somewhat makes sense to me now 😅

[@wtf0101]

So the debate goes on about crossplane and flat-plane cranks, a lot of people say which is better? what puts out more horsepower? What about top fuel? Something to think about

[@rustyaxelrod]

Good video and interesting comments. Ever notice the earlier Ford 302 firing order is the same as a GM V8? They just number the cylinders differently. Not sure about the other ford stuff except I’m aware the 351W and later roller cam 302’s are different. I’m a GM guy but when working on early (non roller) 302 Fords 18436572 will get ya running.

[@jdrok5026]

Its basically the same order.

[@NVRAMboi]

Really helpful and informative video. Thanks.

[@adonian]

simple clear explanation.

[@ellobo1326]

Great video. Great illustrations. Made it totally understandable.

[@henrylucien1842]

Wonderful explanation 👍🤙 I do have to say I've always been a massive fan of cross plane engines that loping sound of a single cam pushrod v8 or even an overhead cam set up... That was until I bought a Shelby gt-350 and reved out to 8500 since then I've decided to build a kit car with a square or over square flat plane engine... Just my preference ofcource but the sound and range of power is just thrilling to me... Btw has anyone seen the hyabusa V-8 n/a or turbo it's an astounding engine... 4-1100 hp and as u can imagine it's very light!!!

[@tomkjr1]

Thanks for the lowdown on cranks!

[@electrolytics]

Good stuff. I was wondering about this. Thank you.

[@InCountry6970]

Superb explanation, thanks

[@BraapZ]

👍Close but not quite. You did a pretty good job of copying/plagiarizing my online published research of the single V8 cranks vs dual plane V8 cranks some 10+ yrs ago on various forums, though you got a couple items a little off. Flat plane cranks fire every 90° of crankshaft rotation like the dual plane does but in a different sequence as you accurately outlined in the exhaust pulse timing of each bank, it does not fire every 180° as you claimed. . Also, “generally” larger displacement will suffer more vibration in a single plane crank but as a result of the stroke and the rod-to-stroke ration, (the 2nd order Harmonic you mentioned), that is the cause of the single planes NVH, not displacement alone. If you build it with a larger bore and shorter stroke yet with the same displacement this NVH will be less. In short, the displacement alone does not determine the NVH with single plane cranks but the stroke AND the rod to stroke ratio does. In-line 4 cylinders suffer the same NVH from 2nd order harmonics and are “buzzy” feeling as a result. Hope that helps clear up a couple of the misconceptions. 😉 BRAAP

[@G55STEYR]

1:10 Sound is at downsides, because it's like a choked stork dying compared to the badass roar of a crossplane big block.

[@christopherolszewski8710]

There's a guy named Michael Cox he runs a 6 liter ls with equal length rotary fire headers in a bronco used to be called the beehive because of the exhaust note. Hoonigans had him on the other day and he was talking about how the truck gained a stupid amount of torque just from creating the scavinging effect in the headers unreal sounding though.

[@bigredracer7848]

Thanks for the great video guys

[@scootergeorge9576]

So it would seem that having equal length header tubes on the cross plane would not be all that critical. The exhaust gas pulses do not arrive at the collector in evenly spaced times. But flat plane engines, being essentially two four cylinder engines could be smoothed out considerably with balance shafts, just as four cylinder engines are.

[@michaelbenardo5695]

They can, but that cancels out the cheaper-to-produce flat-plane crankshaft as far as production costs go. That's why nobody has gone that route. The Oakland V8 of 1930 - 32 is the notable exception.

[@Mandolin1944]

Nicely done video! Very useful.

[@XHikotheproX]

3:50 a V8 has to fire every 90 degrees no matter what as long as it's a 4 stroke engine. There's no such thing as a 4 stroke V8 that either fires every 90 or 180. It has to fire all cylinders within 720 crank degrees.

[@benjaminmcintosh857]

I think he means per cylinder bank

[@mattc.7411]

Opposite=a miss

[@rickmurray7123]

That is correct.

[@bobzwicker807]

That is what I was thinking. The flat plane works like two 4 cylinder engines joined at the crank. Each bank fires every 180 degrees, and the two banks are 90 degrees apart. So why is the cross plane smoother?

[@sergeyakinin997]

@@bobzwicker807 Balance - you can see the big counter weights on the crankshaft for every cylinder on the cross-plane V8. There's no place to attach those weights on the flat-plane. It's why the cross-plane configuration was invented.

[@calesmith3673]

Very well done. Thanks for excellent video

[@TRX450RVlogger]

It's like the old 2.4 Quad 4 Engines made mby GM had a really different idle due to their off self firing order unlike most inline 4 engines they have 2 pistons up and 2 pistons are down the quad 4 engines always had on up 1 down, 1 3/4 way up and 1 3/4 way down.

[@chicagoui9299]

TRX VLOGGER that was a cool motor.

[@brianb-p6586]

That's very strange, because the balance would be horrible and the firing order would be very uneven. I searched, and can find no evidence of this weird configuration - I have found technical descriptions with photos which confirm a completely conventional flat ("up-down-down-up") crankshaft. Check out the Engine Builder Mag article "Rebuilding The GM Quad 4". The 2.4 Quad 4 uses the #4620 casting.

[@177SCmaro]

Flat plane v8s fire every 90 degrees too. 4 cyls fire every 180 degrees

[@fouellet1701]

How can that be if the pins are 180 degrees apart?

[@177SCmaro]

@@fouellet1701 In order to get an even firing order (remember they fire every other revolution) with 8 cylinders 4 of them fire, 360/4=90, one revolution and then the other 4 fire the next. With a flat plane v8 4 cylinders are up, 4 are down, two on each bank (essentially, like 2 flat plane inline 4 cylinders joined together in a 90 degree angle V). Does that make sense? It would be easier to explain with a model.

[@fouellet1701]

@@177SCmaro : Of course, if the cylinder banks are 90 degrees apart. .

[@johnsonbobo2376]

Engineer's explained talks about this and does a great job

[@thebigmon]

I've watched many IMSA races with GT cars and the growl of the C7 and Camaros always turns heads. More than the exotics.

[@rickmurray7123]

The secondary imbalance mentioned here was not explained. It's the same reason 4 cyl inline engines shake or buzz (depending on their size and mounting). In a flat plane crank V8, you have 2 4 cyl engines 90 degr from each other, both shaking. You don't see modern 4 cyl engines over 2.5 ltr that don't have balance shafts. The shake is just too much to put up with over that (the Porsche 3 ltr 924 engine has a balance shaft, for instance). This imbalance is the result of the fact that the pistons are accelerated differently at each end of the stroke. And that is because of rod angularity when the piston moves in a straight line and the big end of the rod moves in a circle. The point in the stroke at which the piston movement changes from accelerating to decelerating is when the rod center line is at right angles to a line between the rod bearing and the main bearing. That puts the piston a little higher than midpoint of its stroke. Longer rods reduce this effect (it affects breathing as well). So the piston has less distance to travel in its reversal of direction at the top of its stroke than it does at the bottom of the stroke. The big end has farther to travel during the lower swing. The piston reverses direction quicker at the top of the stroke than it does at the bottom. That means it changes direction quicker at the top than at the bottom. That difference in acceleration produces different forces at the top and the bottom as well. Remember F=MA? Force = mass x acceleration. The difference in force at the top and bottom is what causes the shake. "Balancing" the parts has nothing to do with it. It is a result in differences in acceleration. "Boxer" engines, by virtue of their opposed cylinders cancel these forces out.

[@michaelbenardo5695]

Yup, a V8 with a flat-plane crank will buzz at certain speeds/loads just like a 4 cylinder engine, but because it is smoother than a 4 at most speeds, when it does buzz it is more annoying.

[@rickmurray7123]

Thank you.@@michaelbenardo5695

[@miniwattnetwork8204]

The traffic junction example is soo real I see it every day on the junction near home