Flat plane crankshafts have been around for a long time, and they have both advantages and disadvantages over their cross plane counterparts. In this video, we look at the differences.
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.
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.
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.
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.
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.
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.
Hold yer' horses!..........Benefit #4 (sound quality) is still open to debate. Smooth Flat-Planes sound cool, but growling Cross-Planes sound cool too!
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.
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...
@tchrisman625 ua-cam.com/video/AYrtPp-OuZw/v-deo.htmlsi=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.
I’ve literally been wondering how a flat plane crank works the past few weeks and every time I get on UA-cam, I’ve forgotten to look it up. Then this video comes up. Thanks man :)
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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?
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
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.
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 🤤
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!
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.
@@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. ua-cam.com/video/9mDhtSYLRyE/v-deo.html
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.
Decades ago a friend of mine hijacked a billet crankshaft complete with wooden box to hold it, from a famous race team. Believe me if I said the name everyone would recognize. So we know this is a sweet piece, but what does it go in? It was a single plane crankshaft or so we through it made sense considering the source. When we took it to a crankshaft grinding shop there was a guy there that just glanced at it and said oh yeah that's a turbo offy crank we were blown away needless to say we didn't have a block for it to fit in or head or other pieces
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.
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).
Two individual crossplane crankshafts with 4 cylinders each joined with gears. Not a V8 but two inline four with crossplane crankshafts. And with a checkered timing pattern.
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 (
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.
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!!!
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.
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.
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.
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.
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.
On a cross plane engine If you put a 5-7 swap cam in it to change the fire order, adjust timing accordingly and Put long tube headers on it... You'll be golden. Engine will turn 8000 all night long smooth as silk
One small error in the verbal description - flat plane crankshaft engines fire every 90°, not 180°. Two revolutions, 8 cylinders, one ignition every 90°, as the cylinder banks are 90° apart.
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.
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.
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!
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.
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
cross planes also have more torque, more balanced crankshaft bearing wear, and with long tube headers that time flow speed, you can actually improve scavenging to levels of a flat plane crankshaft.
A cross-plane crankshaft by itself does not give more torque, rather, traditional V8 engines can't rev as high as 4 cylinder engines, so it makes sense to cam them to be torque-rich, while flat-plane V8s can rev as high as a 4 cyl, so it makes sense to cam them for maximum revs, which is what hurts torque, not the crankshaft.
One correction, even with a flat-plane crankshaft, a V8 has power pulses 90 degrees apart, not 180 degrees. 4 cylinder engines have them 180 degrees apart. The reason flat-plane is rougher is, like you said, secondary imbalance, just like a 4 cylinder engine, so at certain RPM/load conditions, it "buzzes" just like a 4 cylinder. What makes it particularly objectionable is that above and below the resonance points, it is V8 smooth, so it is a big contrast. 4 cylinder engine, in contrast, aren't very smooth at ANY RPM/load condition.
@@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.
The differences in performance aren't not very large a flat plane will make 1-2% more hp but will sacrifice some low end torque. Flat plane really shine in road racing, it allow for the engine to change revs faster so quicker shifting in manual with less wear. It doesn't typical effect the hard red line where the engine is prone to failing, that's mostly a stroke or parts thing. The soft red line is the red line used on productions and is set typically around 500-1000rpm after peak hp. At any rate that is why they tend to red line higher.
Just changing to a flat-plane crank, and keeping everything else the same, won't change low end torque. It will allow it to cammed for higher revs though, and aggressive cams hurt low end torque.
I think you underplayed the counterwieghts. New cross plane V8s are (90sLT1 and then LS and up for chevy) are cooled in a much better manner allowing pretty negligible powerloss due to limits of compression. Its still there. But its a few %. Probably more than the 4-7 swap, but you need much stronger cross plain cranks to allow for the revs that build the horsepower in smaller engines.
👍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
The animation may be misleading, I don't think the flat plane crank necessarily has counterweights opposing each other between the rod journals just a joining flange with a main bearing journal between them since the rod or "crank pin" journals balance out each other.
Yes. I was comparing my F Pace SVR sound with my son's AMG C63 today, we agreed the C63 was louder. Both have that great burble at low revs that I love, plus I have the supercharger whine. 1000HP of magic on the drive. Long live the V8.
Great explanation, and NO robo-voice!!!
Yes
whats so bad about an automated voice
@@paulcochran2212 that's usually means those robo voiced bitches doesn't know that they're talking about and pretty much lack of research
@@paulcochran2212 it is just really annoying to hear in my opinion
Pretty close tho
Incredible video!!! The merging traffic with the JACKASS analogy almost got my coffee spit all over my laptop!
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.
@@Michael_00001 that was 2 years ago...... I don't remember lol. I do love coffee and drink it, so I probably was. 🤷🏻♂️
@@Double_A_Ron I'll accept that 😄
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.
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.
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.
@@testy462 i think it is used by Maserati Granturismo too
@@bobanppvc Maserati engines are crossplane.
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.
Cross plane 8 cylinders have a soft spot in my heart tho. The sound is one of a kind.
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.
Hold yer' horses!..........Benefit #4 (sound quality) is still open to debate. Smooth Flat-Planes sound cool, but growling Cross-Planes sound cool too!
Snowcrest the Yamaha r1 sounds amazing
never heard austin racing 2015 r1 i guess
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.
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...
R1 and V4 panigale sound bad.
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.
crossover headers also solve the issue of exhaust pulse overlap in cross plane v8s. it also makes them sound like their flat plane counterparts.
@Kay Kay the exact technology used by all 2-stroke Performance Exhaust Co.'s
YES! 180° headers have a sound like NO other! Almost shrill! Peace bro, here's to Tune Deafness!
@tchrisman625
ua-cam.com/video/AYrtPp-OuZw/v-deo.htmlsi=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.
I’ve literally been wondering how a flat plane crank works the past few weeks and every time I get on UA-cam, I’ve forgotten to look it up. Then this video comes up. Thanks man :)
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.
'' you can some what'' That's still a no bub.
@@msengineeringdavid3702 pretty remarkable difference though
It’s not somewhat, it’s actually done and works
@@msengineeringdavid3702 individual pipes will
It's worth nothing that dragsters with straight-cut pipes have ZERO issues with uneven firing.
Well, I think BOTH the cross-plane and flat-plane V8s sound AWESOME.
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.
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.
Ducfandan, AGREED, I had a set of tuned 360 headers on my big block ford. and they work, but what a nightmare to install...
Exactly the comment I was searching for, you literally took the words out of my mouth. 👏🏻👏🏻👏🏻👏🏻
Awesome follow on explanation - thanks!
Thank you..
Excellent graphics used here to help picture and describe these two approaches to V8 crankshaft design. Thanks!
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.
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.
Its not possible to have a flat plane v6.
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.
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.
Best description I have seen. Having 2 cars with Flat Plane cranks, and one Cross Plane, I never quite understood the difference until now.
This is the BEST VIDEO on UA-cam for this topic.
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.
Whoa there! Better sound? That's pretty relative. I like both but the crossplane is my winner
Very nice explanation. Informative, mature, and professional.
8ŕõrõo::opróóçcdččćvcčć'ćć'
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!
This video was an outstanding informative and concise demonstration of the flat plane crank. Exactly what I was looking for. Great job!
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.
Great video, very educational and simple to understand. Cant wait to watch the rest of them! 👍
this was a very well made, understandable and smooth video. nice job!
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.
Yup, if it fired 180 degrees, it would be running as if it was a jumbo-sized 4 cylinder.
I wondered why Euro V-8 engines sounded different, now I know. Thanks.
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 👍
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?
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
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.
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 🤤
Absolutely OUTSTANDING video
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!
Excellent discussion and video.
This is the best explanation of the differences on UA-cam. 👍🏼Well done.
EXCELLENT EXPLANATION SIR. THANK YOU FOR THE EDUCATION!
With tuned exhaust, the pulses can be timed and corrected with the dual plane crank.
Exactly
It is essentially just an air pump
a 180 degree header fixes the problem of the incorrect scavanging pulses. makes a sb v8 sound like a ferrari
@@SchafdoggGTO im in it for performance. chrome and sound doesnt get you down the track any faster.
@@SchafdoggGTO - I want the sound of a Big Block, myself.
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.
@@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.
ua-cam.com/video/9mDhtSYLRyE/v-deo.html
MrHillfolk you my friend have impeccable taste .
The more you watch these videos the more you learn. Thanks and thanks UTUBE
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.
Great way of explaining it!! 2:13 caught me off guard LOL
Excellent video, very concise and informative
You definitely need to do more videos. I personally love them and wish I could see more of them!
This was totally informative. Thank you very much!
Excellent video. Well done! It somewhat makes sense to me now 😅
Decades ago a friend of mine hijacked a billet crankshaft complete with wooden box to hold it, from a famous race team. Believe me if I said the name everyone would recognize. So we know this is a sweet piece, but what does it go in? It was a single plane crankshaft or so we through it made sense considering the source. When we took it to a crankshaft grinding shop there was a guy there that just glanced at it and said oh yeah that's a turbo offy crank we were blown away needless to say we didn't have a block for it to fit in or head or other pieces
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.
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).
@@brianb-p6586 yes- great point. The difference in sound between a WRX with UEL headers vs EL headers is pretty significant.
Two individual crossplane crankshafts with 4 cylinders each joined with gears. Not a V8 but two inline four with crossplane crankshafts. And with a checkered timing pattern.
better explanation than engineering explained, I like the animations you did
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 (
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.
@@michaelbenardo5695 Agree, they don't float my boat either.
Great explanation! Easy to understand. Thanks!
Dude you made that so simple to understand.... thanks
Thank you. I was going to look this topic up today and now I don't have to!
Fantastic video. Thanks for putting the time into producing it.
The traffic junction example is soo real I see it every day on the junction near home
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!!!
Loved the traffic analogy
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.
Its basically the same order.
Very well explained, thanks!
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.
TRX VLOGGER that was a cool motor.
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.
I have one of these in my GT350, love it! Great video, too!!! I laughed at 2:15.
Thanks for the vid and explanation! I love the sound of my GT350!
Thank you this was really helpful to my studies
Thx - very cool explanation. Now I know how it really works
Superb explanation, thanks
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.
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.
Finally understood the difference and significance!! Thx, great vid.
On a cross plane engine If you put a 5-7 swap cam in it to change the fire order, adjust timing accordingly and Put long tube headers on it... You'll be golden. Engine will turn 8000 all night long smooth as silk
Personally I'd take the crossplane sound (and philosophy) over that of the flat-plane any day of the week.
One small error in the verbal description - flat plane crankshaft engines fire every 90°, not 180°. Two revolutions, 8 cylinders, one ignition every 90°, as the cylinder banks are 90° apart.
Good job in explanation and illustrations
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.
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.
Thank you.@@michaelbenardo5695
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!
I appreciate the work youve done in this video
1:10 Sound is at downsides, because it's like a choked stork dying compared to the badass roar of a crossplane big block.
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.
Very informative and well explained video. Great job!!
Concise information delivered in a professional manner. Most satisfying Utube experience. Harumph.
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
Chris Great explanation. Thanks!
cross planes also have more torque, more balanced crankshaft bearing wear, and with long tube headers that time flow speed, you can actually improve scavenging to levels of a flat plane crankshaft.
A cross-plane crankshaft by itself does not give more torque, rather, traditional V8 engines can't rev as high as 4 cylinder engines, so it makes sense to cam them to be torque-rich, while flat-plane V8s can rev as high as a 4 cyl, so it makes sense to cam them for maximum revs, which is what hurts torque, not the crankshaft.
@@michaelbenardo5695 a traditional v8 can rev past 10000rpm they’re found in nascars
Great video like the explanation and the visuals
One correction, even with a flat-plane crankshaft, a V8 has power pulses 90 degrees apart, not 180 degrees. 4 cylinder engines have them 180 degrees apart. The reason flat-plane is rougher is, like you said, secondary imbalance, just like a 4 cylinder engine, so at certain RPM/load conditions, it "buzzes" just like a 4 cylinder. What makes it particularly objectionable is that above and below the resonance points, it is V8 smooth, so it is a big contrast. 4 cylinder engine, in contrast, aren't very smooth at ANY RPM/load condition.
well explained
Good ole build Chevy v8 sounds best to me, good vid👍
Best explanation ever !!! Thanks 🙏
Flat plane v8s fire every 90 degrees too. 4 cyls fire every 180 degrees
How can that be if the pins are 180 degrees apart?
@@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.
@@177SCmaro : Of course, if the cylinder banks are 90 degrees apart. .
Engineer's explained talks about this and does a great job
That's why tuning lengths of header runners is important.
Very well explained. Great Job!
Awesome video, hope they keep coming
The differences in performance aren't not very large a flat plane will make 1-2% more hp but will sacrifice some low end torque. Flat plane really shine in road racing, it allow for the engine to change revs faster so quicker shifting in manual with less wear. It doesn't typical effect the hard red line where the engine is prone to failing, that's mostly a stroke or parts thing. The soft red line is the red line used on productions and is set typically around 500-1000rpm after peak hp. At any rate that is why they tend to red line higher.
Just changing to a flat-plane crank, and keeping everything else the same, won't change low end torque. It will allow it to cammed for higher revs though, and aggressive cams hurt low end torque.
You have a power stroke half has often that will result in less torque
@@michaelbenardo5695
Really helpful and informative video. Thanks.
I think you underplayed the counterwieghts. New cross plane V8s are (90sLT1 and then LS and up for chevy) are cooled in a much better manner allowing pretty negligible powerloss due to limits of compression. Its still there. But its a few %. Probably more than the 4-7 swap, but you need much stronger cross plain cranks to allow for the revs that build the horsepower in smaller engines.
The d346 Caterpillar engine was like this and had dual over head cams per head
👍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
Thanks for the lowdown on cranks!
Thanks for the great video guys
The animation may be misleading, I don't think the flat plane crank necessarily has counterweights opposing each other between the rod journals just a joining flange with a main bearing journal between them since the rod or "crank pin" journals balance out each other.
I actually much prefer the sound of a cross plane V8. It has the classic V8 burble that is very appealing to me.
Yes. I was comparing my F Pace SVR sound with my son's AMG C63 today, we agreed the C63 was louder. Both have that great burble at low revs that I love, plus I have the supercharger whine. 1000HP of magic on the drive. Long live the V8.