Это видео недоступно.
Сожалеем об этом.
Theoretical look at why the 4V Cleveland got its port size.
HTML-код
- Опубликовано: 30 мар 2024
- Sometimes, things are so obvious, they have to be the problem... right?
No.
The internal combustion engine is a beautifully complex thing. Something as simple as a port size is not "simple" due to the dynamic nature of camshaft, exhaust, compression ratio and intake manifold. Then there is the intended rpm range it is designed to operate in.
This video is a more in-depth theoretical look at piston driven induction and what is needed to maximize the energy transfer from pumping loss to air speed.
The interesting thing about the Cleveland head is that the factory published data from Ford when the Cleveland was current, was at 5" Hg, or 63" H2O. They compared the head to some of their competitors in the published data. Low end flow wasn't that different, but high end flow differences were massive, and stable. For a number of years now I've said that the greatest weakness of a Cleveland is team small port engine builders. They just don't understand the difference in the design concepts of the motor. Very few people understand how important closing the intake valve early is on a Cleveland, and how important the exhaust depression during overlap is to running engine intake port velocity on a Cleveland.
Spot on, the factory Cleveland 4V just doesn't fall flat up top.
Exhaust depression?
What youve just said is shorter duration with a tight camshaft LSA .
Yeah, if I had a dollar for every time I've heard someone say that the 4V Cleveland had no power on the bottom end, I would have a hell of a lot more in my retirement account.
These people don't understand is that you need flow just as much at low RPM as you do at high RPM.
What Cleveland's did not like, as far as low end torque was concerned, was the high duration, low vacuum cams.
Pretty much the point of what this gentleman is talking about. I didn't have a flow bench, or Dyno, and I learned this by accident. I put a milder cam in mine than all of my friends were using, because I just wanted a bit more power for the street. I ran a cam that was recommended for 1800 to 5200 rpm, a lot of people call this an RV cam, but since I had ported heads (conservatively ported) with 3 angles on the seat and 2 on the valves.
Long story short, it was not only stronger on the low end, it kept pulling to 6000.
I found this out on the strip, racing another 4V Cleveland that had a strong rumpity rump lope, while mine was much smoother. I didn't expect to win, I launched faster, and did not shift until I stopped pulling away, which was about 6000. That is all it did. So I started researching why. It was always the cam choice, and all the people who just threw parts on them with stock heads.
@thisisyourcaptainspeaking2259 at the end of the exhaust stroke, the velocity of the mass of the exhaust gas travelling down the exhaust creates a low pressure area in the cylinder. This is why valve overlap makes such a difference to the way a cylinder charges during the induction stroke
NASCAR HEADS.. Wide Open Throttle, made to beat the Hemi.
The Aussie 2v's are the ultimate production street head for in the Era.
The 351C was the most handicapped engine in PS racing for a reason. Bob Glidden dominated the field with his Cleveland powered 78 Fairmont and never lost a round, race, or event. The 500 in³ rule was a result of the most badass pushrod smaller in³ engine at that time. Current NASCAR Ford heads still retain Cleveland DNA to this day.
Bob dominated in 1979, and Ford had nothing to do with it.... At the end of the day the engine brand had little to do with it, and the team had everything to do with it...
The 4V head was developed for Trans Am and was used on the Boss 302. This type of racing requires a high reving engine so the low end torque can suffer a bit but the top end will pull away from the competition. Bob Gliden stuffed the ports to get some of the low end back for drag racing as this is a different application. He also raised the intake and exhaust ports for a more direct line to the valve. On the exhaust side of the head is the worst restriction due to fitting the engine in between the shock towers of the Mustang. Cam timing and overlap is critical with the Cleveland canted valve design. If you run a cam design for inline valves you can lose some of the intake charge out the exhaust. For normal street use the smaller ports seem to work a bit better due to the increase in low end torque. For high rpm the big ports are the way to go and make sure the cam matches what you are trying to accomplish.
Not always true. I've had a boss 302 in my 68 F-100 with a C-4 for 30 years now.
Has excellent throttle response.
Better mileage and driveablity than an FE.
Depends how you cam the engine.
During the mid to late 70's, we ran Cleveland power and found nothing responded compared to inline engines. Took a while to decide that no matter the camshaft, there was no effect until -- we decided, because what we had been doing came from the Monkey See-Monkey do. Steel billet cams were I think about 200 bucks(?). So a cast iron was 50-75 bucks(?). I talked with the grinder about trying 3 different grinds by spreading the lobe centers. We knew we'd get a couple two-three hits before the cam chipped out. This was something I had done on 4cyl engines to learn how they responded in dyno efforts. -- So, the first stick was the same grind with the lobes moved 2 out and then 2 more and 2 more.
We saw the trend right off and each stick not only improved times but speed as well. The grinder got wound up too and suggested we pull duration out in steps, and it responded as well. So with a huge savings and plenty of magnets, we learned more about that engine compared to any other small block. At the end, 113 is where we got good results. It would really reach for the next gear compared to prior engin mods. -- So, we gained significant valve to piston clearance in which we picked up notable compression. It was finally fun seeing it wake up from simple working around camshafts.
Erson Cams gave us the success and knew what we needed as we did the work. Don't doubt those boy's. At least during those years, they had our best grinds and cause and effect.
I remember the Viking cam in a cleveland. Pulled hard.
Thanks for your video. I like the approach to describe in layman-ish terms, the dynamic relationships between induction, ports, heads, ram air, fluid dynamics, rpm and power. For a while I thought I installed a cam with the wrong valve timing, wrong LSA, duration. But I’m confident that at least a narrow rpm band, it’s optimal 😂
That's why Cleveland's like rpm
Basically the 335 series was a 385 series downsized with some additional upgrades. Port and chamber designs were similar.
But the 385 had enough capacity and oiling to use said ports.And are heavier again than a 335. Especially the lump of 400.
Richard Holdener compared all the muscle car engines of the 1970 era and the 351 Cleveland was at least 30 HP ahead of the competition. He also found the torque levels at low RPM were as good as the competition.. Ford definitely had the edge in horsepower and torque.. Sorry Chevy guys
But the Ford cost twice as much to build, and had to be rebuilt twice as often. And yes I have built good budget Chevs and then good budget 351s which are a LOT more expensive. As for Holdener,, yes some of his work is interesting but most is hack work.
They figured that out after they copied the Big Block Chevy for 1968.
They just had the dumb idea of putting it on a small block.
Good stuff. Thank you for that informative video.
It's true, each component in an engine should match the combo and intended use.
A very important thing you didn't mention, is the air flow is rpm related. That air velocity vs crank angle graph you showed is a snap shot of a particular rpm. 500rpm later, that graph would look completely different.
The universally accepted rule of thumb "small port=high velocity=more torque." Sounds good in theory, but I've seen many actual dyno tests which prove it wrong. Often, a bigger port makes more torque and more power.
Interesting I would like to see some solid data on the 4v Cleveland I was told they run about 500rpms below the 2v in low lift is this true.obviously after 4000 rpms the game changes.
@rossgirdeen3247 go to Richard Holdener's channel if you haven't already. He has done dyno testing on replica boss 302's and 351's against the other performance engines of the time. These are factory standard engines. The Chevy DZ302 makes a little more low end torque than the 302, but not much. Top end hp, well, you wouldn't want to be a Chevy driver. The 351 is a different story, it out torques and out powers everything else in the class across the entire rev range. Along with much better idle quality due to the factory using much less cam to make the power
@@theshed8802 yeah I always hear people say there there no good to big but all the Dyno pulls I've seen say differently.
Some consideration on intake closing point is the quality of the fuel. If the cylinder goes into detonation because you have trapped too much fuel/air charge, and end up with a too high dynamic compression ratio, you cannot utilize the additional charge of a later intake closing. So the closing must be tailored to the fuel available.
You can not trap "too much" charge, thats the whole idea of making power.
The stock cleveland head flows near 300cfm. Nothing produced at time flows close in sb world.
An internal combustion engine is like a tuned instrument, changing one part might make it a lot worse, all parts from the air intake to the exhaust tip have to work in harmony.
A certain number of things fall into place if we think about overlap window in terms of milliseconds at various rpm.
good stuff,,, wonder what swirl and tumble numbers they saw back then ? how much diffent did leaded fuel atomize then modern fuel etc
Understanding fluid and gas flow with a mechanical pump goes a long way to understanding the magic of getting maximum flow to convert into fire to produce the results desired..
It's not a pump
@@michaelgiglio1571 if its not a pump then what is it..
nice video
Ford large port 4v was for racing big rpm not for street use but homologate regultor of NASCAR etc brought them to public ,Ford's engineering knew exactly what they were doing and achieving they had more experience than average joe with a couple of vacuum cleaners ,drag racing ,le mans ,trans am ,canam ,nascar etc the list is longer than a flow bench
formula 1 could be added to the list as well with their joint effort with cosworth. the Ford/cosworth DFV engine was the staplehood of F1 when they were running N/A and was regarded as a masterpiece in mechanical engineering by nearly everyone. i think honda had their own engine and of course Ferrari didnt care for Ford, so they ran their own as well, but not without issues
All Hale the nascar Era for performance practices.
The Ford engineers knew exactly what they were doing. The problem is the average person doesn't and they can't understand what the Ford engineers had in mind.
There is a epidemic of "Chevy on the brain" in V8 engine circles and that is a fatal error when working with a Cleveland.
You must get into the mind of the Ford engineers and ignore what is done with other engines.
As far as 4v ports, look up Bernoulli's principles of diverging and converging passages.
Although a bit of a technicallity, the engine does not draw fuel air mixture into the engine. The air pump (engine) creates a low pressure area in the cylinder and the outside atmospheric pressure "pushes" the mixture into the engine. The ability of the mixture to be pushed into the engine is controlled by the intake tract, (port sizes, shapes, valve opening, ect). This is simply referred to as volumetric efficiency or VE. The mixture is never streched it increases in velocity due to the fact that all the air available is pressed into a smaller orifice called the intake tract. The easier the mixture will flow through the intake tract the better the volumetric efficiency or max VE. This explains why when the throttle blades are closed low pressure reading below the blades is higher because the engine created low pressure area is u able to be filled as easily when the intake tract is closed to outside pressure.
You have most of that right, but you miss a VERY important point - this is not a steady state condition, but is continually varying.
As such, the inertia of the air-fuel mass is a critical consideration when selecting the engine parts for that specific build..
I have to disagree on the "push" explanation on the basis of energy transfer. Sucking is taken on the first half of the stroke as an engine has to consume energy. Pushing refers to an external energy that creates movement. The push comes after, in the ram phase. Which is more a combination of inertia effect from the initial "suck" phase and the push from what pressure is in the plenum. The reasoning for this is that the pressure trace after 90 degrees always heads down as the cylinder pressure equalizes.
The strecth description is chosen in terms that when anything is stretched, it becomes thinner. As said with Rule One, velocity is traded for decreased pressure, so energy between the two states (rest and movement) remains the same. The greater the depression, the greater the weight loss, and the greater the speed. Since inertia is the combination of weight and speed, then the trade-off of reducing weight to increase speed to increase inertia will plateu and fall. Or, in other words, the energy required to accelerate the air will exceed the energy potential that can be trapped in the cylinder. This process begins past peak torque, which I suspect is much earlier than most realize.
@@crd-nz_001
You may wish to review that in terms of absolute pressure.
I suspect the use of "stretch" may be confusing, as it may mean different things to different people - perhaps "elongate" will please the gentleman more?
I can understand you using it as in "gauge" terms one may think of the depression in the cylinder "pulling" on the charge in the port, but I'm more used to working with "absolute" pressure, as the other chap may be?
It does confuse it somewhat, unless one thinks very carefully what is happening in the port, regarding pressure and velocity gradients.
Good watch, and some good points and thoughts on your part.
Might need to give the exhaust side a little more attention - remember, the piston has to impart the energy into the exhaust for it to "scavenge', and that energy is largely provided by the piston excerting pressure on it.
On that, IIRC, the exhaust port design wasn't as sound as the intake, but been a few decades and the brain gets foggy?
I think Chrysler were running the W2 head on the 340 'X' block with a 360 stroke, (358 was the actual cubes of the 360 I believe, so they (nascar) could allow for each manufacturers biggest bore smallblock) For a time the Chryslers were the go-to smallblock and the Cleveland didn't surpass it until the early 80s with development really, and Chrysler went broke at the end of the 70s anyway and most people switched over to Ford or GM
No motor in racing history has been penalised more than the Cleveland. In both Nascar and ProStock, the Cleveland had to carry more pounds per cubic inch than any other motor in history, including the hemi
Also to add to theshed's statement the Cleveland head platform is the winningest head design in NASCAR history and was solely responsible for the demise of small block Pro Stock and Super modified drag racing classes in NHRA.
Um, not in reality. No small Mopar is superior to the Cleveland head.
@@chadkent1241 Well, those were the words of Maurice Petty. And I wouldn't take him for a fool or liar for one minute. If the Ford was way ahead, I'm sure they would have just switched camps. Don't forget the fancy Cleveland C2 head weren't around back then.
So if we close the ivc early does that mean we start it earl? Lengthen the exhaust duration? Tighten the centers? What would you summarize regarding valve events? Thanks for this insightful video
We have to be careful around the overlap of a Cleveland. It's not just low lift flow that makes it have great potential for exhaust scavenge, but how sensitive they are to the exhaust as a whole.
Im dreaming up the equipment to test/show this, but first, I need to get the flowbench capable of pushing air through the exhaust port. It is this side that is the trouble, and I think many will be shocked as to why. (It's not just the low cfm flow either...)
Good thought experiment, thanks. I hadn’t thought about the restriction p
Area but you may be onto something there. I do believe that the 4v heads were designed with high performance in mind,which is why they are a bit lacklustre at typical street trim and 351ci. They seem to work very well on 400+ inches.
A couple of comments. Your CFM calculation overlooks the fact that the intake is only open on every second revolution, so the calculated CFM number is half of what you found.
But on the other David Vizard teaches us that on a well built motor at peak torque the so-called 5th cycle actually brings in more air than the rest of the induction stroke.
Anyway, I don’t think either f these points changes your conclusion.
“Restrictor plates” not “restriction P area”
Thank you.
While the calculation is experimental, I didn't account for the 4 stroke (so half the rpm) because this is the theoretical demand the piston creates in the first 90 degrees of rotation at every induction stroke. Projecting the demand to 60 seconds fills in the Minute part of CFM.
I also calculated this way as taking average piston speed would only give average cfm demand throughout the complete intake stroke and ignore the piston driven induction to ram induction. This would lead to conclusions that the 4V port is "too big".
I was born in '69, same year ford released the boss 351 mustang, and can confirm that ,dispite my reluctance to believe it, that was 55 years ago.
1960 myself and it sucks.
Boss 351, 1971 only
@@stevo196two9 forgive my lack of mustang knowledge. We got what was touted to be the "boss 351" engine in our XY Gt phase 3 falcons (australia) in '71 so i presumed you guys had them before that. What differentiated the "boss" from any other big port cleveland in mustang terminology?. I would have thought the '69 mustang cleveland and '71 were the same?. Solid lifters in the boss?.
Mate, excellent video for explaining the 4V concept to non-Cleveland people.
I could see you struggling to communicate your innate understanding of the subject while on the fly, maybe you'd benefit from doing a script for it, so you have to time to articulate your thoughts?
I share a lot of your views on the design principle behind the big port, but I'll add some points that I think are pertinent to the history and racing success of the design, as well as the reasoning why the concept became a dead-end.
Now before all the Ford freaks out there start throwing tomatoes at me, I'll let you all know that I'm a Ford guy myself, however to know a marque well is to know its faults and where their ideas may have stemmed from (ie not necessarily from the company itself).
In the mid 60s, Ford poached a number of engineers and managers from GM. This coincided with the Cleveland and 429/460 head design sharing some elements from GM engines: namely the Chev big block and Oldsmobile V8 (head design and timing cover/fuel pump respectively). So the ideas came with them.
If you ask any BBC expert, they'll acknowledge that there are "good" and "bad" ports, where the equally-spaced, canted valve arrangement was adapted to siamesed runners on the intake manifold, presumably to keep the intake tracts all the same length from carb to valve. This may have achieved the desired objective, but created the aforementioned good and bad port situation.
The bad ports shoot the intake charge towards the cylinder wall, the good ports have it pointing towards the spark plug (ie centre of the cylinder). There is a good 20 cfm difference between these ports, stock or ported, which means that this is a flaw that cannot be completely worked around.
I would then argue, that due to the Cleveland's cylinder head bolt layout and pushrod location having to match that of the Windsor, that the port direction is actually like those of the "bad" ports in the big block Chev. Again, there is no working around this flaw, as (when viewed in plan view) the port opening starts roughly inline with the cylinder bore, then curves outwards towards the cylinder wall. This is the opposite to how the air really wants to flow, and granted, the canted valve helps turn the mixture back into the cylinder, but that's another turn (and loss of energy) that the mixture encounters. This is present in the 4V port, but more noticeable in the 2V.
I think in hindsight, with such constraints put on the design, that Ford would have benefited with an extreme bias toward curving the mixture more gently into the middle of the cylinder, instead of having it heading completely in the wrong direction then trying to correct it right as it turns into the valve.
Any thoughts on this?
Yea, a script would help with articulating ideas in a more consice way. But, like the work I try and convey, it's raw and uncut. I don't see myself as a professional and hope to promote positive experiences and debate from normal individuals. I have no issues with the various points of view. If I disagree, I will say why. However, this channel is just a collection of my ramblings that one day I might have the chance to build a Cleveland to put into practice the theoretical I am trying to get across. Let's face it, a 30-second video of a 12-second 1/4 mile makes more of an impact than 30 minutes of chat.
The 2V assessment would be accurate as once a 2V hits 0.4in lift, flow effectively chokes. No matter how much value lift, flow does nothing. In some cases, flow reduction
I will have to include a modified 2V in the head review I intend to do. It has been opened above the spring seat and reshaped using clay. Flow improvement over stock was 30cfm. It raised the port about an inch, so it was very experimental. At best, it would be easier to replicate this work on an alloy unit if it were to be tried on an engine. But financially, I'm just not there by a long shot.
The short answer is they were designed for long distance, foot on the floor, circle track racing, like the Hemi. They are pure junk for acceleration performance (drag racing..)
Bob Glidden spent tens of thousands of hours modding them, to the point of sawing off the exterior exhaust ports, machinging a port block to bolt the headers to!
The 4Vs were still better
Raising port floors..
The Aussie 2v's are the ULTIMATE street head..
Oh, just junk for acceleration. Why he chose to sandbag himself, who knows? He also ran engines in the 320 to 330 cu. in. displacement sizes for weight breaks, which NHRA kept adding on to the Clevo.
@@rondye9398 you talking about the BOSS 302?
@@nobiden3134problem with that statement, nobody has tested them.
Does any of this information transfer to the inverse such as a big block Chrysler head which has very bad flow characteristics?
In general terms, if the port is large, then it should respond to an early intake valve closing.
As I have no experience with Chryslers (yet), I can not give any form of opinion as I have no basis to give one. If it's related to the RB Wedge head (I think that's what Chrysler called its big block range - RB), then there could be other features in the port/chamber that give it bad flow. Until I have one in my hand, I simply don't know. I say this head as the Hemi has got giant ports, so it should fall under the same category as a Cleveland.
Would you agree the 2V closed chamber with good port work and giving 11-1 is the way to go for street n strip. I think so. Mike
I built my first Cleveland almost 20 years ago that way. 302C heads, 20tho off and towing cam (260 advertised duration, 0.5in lift) Aprox 12.3:1 compression. It relied on mechanical advance only for timing as vacuum advance just caused knock. Sadly, the valvesprings let it down, going into float at 4900. Still, it made 340hp. It wrecked a C4, numerous 6 cylinder diffs plus a 9in along with countless rear tires.
The fastest I got was a 9.2-seconds over 1/8 mile from a 3600lb Australian 4 door Falcon from a 3 speed C4 auto, stock converter, and 3.23 rear gear.
@@crd-nz_001 Cool, sounds like a combo I had 20 yrs ago as well, only I had open chamfers with a 292 Borg. It well well on the street. Now I want compression and geering,. IV used these closed 2V and noticed 6-7 th RPM is no problem and strong from the start to end so why change, and I have choice of manafolds and pipes. Also cast heads are Quilty. Hey great podcast thanks mate.
some of the old guard liked to raise the 4V port floors with epoxy to get a better drop
@@crd-nz_001I have a 351c, closed chamber 302 heads,, 750 vac/sec and 3.55 9 inch in my Xb Falcon. Gets driven regularly, just a great all-round cruiser.
@fastst1 people forget its vacume, it will draw from anywhere. I don't think it helps and Then the flow ratio's are wrong.
I owned a 71 Boss 351. The factory forgot to install a thing called torque.
4v Cleveland any good books there's alot of conflicting information on this engine.
I wish I could say there was a solid book on useful information. The "How to Build" book of the 80s (contains 351C/M and 400), which sticks strictly to stock engine builds, is very good.
Besides that, I have to agree. Most books are over 30 years old, and any new ones discard the 4V head as no good.
@@crd-nz_001 that's what I hear people say ?they seem to do good on the dynos though theres other folks online say the 4v is ahead above all engines of that era and displacement. They always seem to do well downlow in the rpm range on all the tests I've seen. What Head of that era is any good compared to all the aftermarket aluminum heads out now.
draw-ing?
Ford spent a lot of money designing the Cleveland engine.