Head was a modified section. Swirl is the amount/speed of rotational air. Tumble is more vertical. Swirl is important in these engines to keep the fuel atomized in the air all the way into the combustion space. But I dont know how much you can get away with losing before performance drops. The question has also been asked, if you build a manifold, will the swirl come back up? I'm not sure but if someone builds something and wants it flowed, you can contact me. Side note here but if you guys want heads done by us, we are MORE than happy to port them for you. I've done some development on these with the bench and I think I've found all the key areas for flow. I'm sure Greg has some tricks of his own due to the amount of nailheads he has done. I can tell you that the valve and the bowl areas are CRITICAL. as far as shape. You could put 2 5mm valves in these heads with different 'tulip' shapes and it would change flow drastically. Mike
Somethig about Germans. What, did they also do these head mods first, then come here and work for Buick? Coool....:idea2:
What was that all about.? i'm guessing it has something to do with this tagline in Nimrod's sig area: the "truth" is a lie you believe until you know better SJ66 made some comments about American scientific accomplishments from the 30's to the 60's on page 2 and Nimrod seems to have decided to edumacate us ignorant Murrican's on what the "truth" is. didn't you americans get some or most of your knowledge on the atom bomb from our german engineers (otto hahn, edward teller, the swiss einstein) you mean the Jewish nuclear physicists that Hitler ran out of the country? yep, they did us a bunch of good in the Manhattan project. over here, we view it as a great irony that we obtained the singularity that would supercede all possible 'alternate history' outcomes of WW2 via Hitler's foolish decision to sanitize Nazi science of the 'corrupting Juden influence'. you seem to have a very odd conceptualization of how physics researchers work. they meet and exchange information across national, language, religious and philosophical lines all the time. nationalism is not normally a high priority to people like this, especially if it interferes with the development of knowledge. and your clever espionage? a good indication of how essential the Deutsch contributions to the American nuclear program is the fact that not only did Germany not produce a fission bomb of their own, they were never going to get one developed using the heavy water experiments. and weren't some of the most important NASA engineers formerly german nazi engineers like mr. von braun when has the US ever tried to "hide" von Braun's contributions to our space program? but since you wanted to bring up where a country got it's 'knowledge' from, you can now thank the US for Robert Goddard who gave von Braun the liquid fuel technology he needed to do most of the things he did. most of Russia's space program was also based on German physicists that they hussled out of the country. i wonder which country they would have preferred to be working for, post 1945? of course, most of what Russia didn't get by kidnapping German scientists they got by espionage in the US and other western nations. and didn't come some of the NASA engineers from canada due to the political cancellation of the avro arrow? now you're saying the 25 Canadian phycisists and engineers were the tipping factor that made the moon shots a success? i thought it was von Braun? or maybe you're just confusing me ... i guess we should have just left them unemployed? and wasn't stealth technique developed by the germans in WW2 (e.g. the gotha and the horten HO mono wing planes)? ummm, you're asserting that "stealth" was a primary design goal of the early flying wings? i don't even know what to say to that. Nimrod, keep in mind that most of my heritage is German farmer stock from northern Indiana ( deep Amish and Mennonite country ). i certainly wouldn't try to underplay the accomplishments of German technology and science from 1900-1945 but there's little point in trying to over-reach like this.
Yup, people who were smart enough to get away from the nazi's and then work day and night to make sure they couldn't take over the world. And some other people who wanted a job. Hitler didn't like those sort of people anyway.
Considering that the "Swirl" on a "Nail" is in the 4000 range I don't feel that a reduction of 100-800 would be that significant in comparison to some "Good" & "Excellent" aftermarket heads that have a "Swirl" in the area of 2800. In this case the intake design is a very important factor to consider. Every application would be different depending on cam & head flow numbers. Who has the time, & most importantly $$$$$, to accomplish this & when they are done & ready to sell they are told "Gee, Kind of Pricey!!!!!". Just my opinion.
in the old days of the internet the quickest way to end a thread was supposedly to mention Nazi's or Hitler... Unless Buick had a former Nazi engineer on the nailhead (who knows) this all seems to be a turn for the worse. For the record I was objecting to the hasty and I'm sure not truely intentional comment that 50's technology was "voo doo". No one here is going to say that Germany hasn't produced some masterful engineers. But no American here worth a damn is going to agree with the idea that all our scientific and engineering acomplishments are due to former Nazi or non-Nazi German/Jew/Gypsy/Pol etc. Lest the World forget we are all very recently "former" Europeans, we had no problem cultivating the greatest minds in History pushed away by the most powerful idiot savant in history bringing them over and embracing them as "one of us" because we all pretty much to a man used to be "one of you".
Those WW2 engine guys really knew what they were doing IMO. That S shaped port evens out the long and short sides. Maybe they had plans to use the Rochester port injection like Chevy had in the mid 50's. Imagine what that'd be like. Straight tubes with a big plenum on top. Wild stuff.
4000 swirl on a Superflow bench with a Superflow brand swirl meter? What does 4000 represent? RPM's of a certain size fan blade based swirl meter, I'm guessing? I believe your numbers. I'm not being sarcastic just trying to figure out where your swirl number comes from. If you and mike have different swirl meters or bench setups your numbers wont be the same. Just changing the meters position inside the stack will have drastic effects on the reading. On the other hand I'm not surprised to hear that the nail swirls very high, because every small fact I learn about nailheads (like air flow control nodules) leads me back to the conclusion that the Nail is superbly designed and tuned for its intended use, and takes advantage of some ideas and technology that 40 years later are only just being learned about by aftermarket companies and the common gear head like myself.
Simon. now you know some of the reasons many of us are so intrigued by our ole "Nails". SOOOOO much to learn & so little time. The same bench & methods are used in this comparison on flow & "Swirl".
yep, i tinker with them, but i like them just the way Buick made them.... You cant argue with success... There is just something about a good running, dressed out nail.... that and every body and his dog and cat dont have one of them....
in the old days of the internet the quickest way to end a thread was supposedly to mention Nazi's or Hitler... Godwin's Law is still extant.
I have a fairly hogged out set of heads with the nodules removed and they perform very good. Was considering milling the intake as you described and making a sheet tunnel for it. Ive found on the B4B, the more plenum you give, the more it likes it. The interesting thing is the exhaust. They reflect out of the bottom of the port.
Superflow 1020 Bench. AudieTechnologies swirl meter. Doesn't have a fan, it actually has probably about 200 orifices (think vertical straws) of which air turns it any which way it pleases. Comparisons were on the same bench. Same set up. Swirl meter is indexed based on the 4 mounting location bolts. Nailhead has around 3200-4000 RPM swirl. Most aftermarket 23degree SBCs have like 2500-2800. These engines intake tract is the key to where, when, and how much power you have. One little slip can throw a good combination off. Regardless, as we all know Tom says 'It just wants more AIR!!' and it will take it anyway you will give it. Either dual 4's or a sheet metal intake with a 1450 Dominator! LOL Mike
A little quick and dirty photoshop fun makes me wonder about a four-valve nailhead head. I don't have a clue about the feasability, I just thought it looks awesome.
Does anyone know for sure if these nodules were put there intentionally? The ones in the entry of the intake port look like they might be functional. But why are there nodules in the EXHAUST ports too? I suspect they may just be part of the casting process, and were not in the original design of the head.
On the theme of interesting head modifications... What is it exactly that Greg Gessler does that makes them flow and perform so much better? Is it just pocket and bowl work, or a significant level of porting, and does he leave the nodules in? If I read things on the website correctly "all of the above". I personally have never seen any of his various levels of reworked Nailhead heads. What does the torque and HP bands look like with those modifications? Anyone have real data? Voo-Doo, Shmoodooo! Call it what you want, but, I know it wasn't pure luck! Did they just get lucky and stumble upon the pent roof chamber design? I don' think so... Did they get lucky and produce mass amounts of low end torque to get big cars moving of the era? I don't think so... Did they get lucky and discover "swirl technology"? No, They probably knew what they had and took advantage of it. Who knows what they called it, but it worked. My question still remains: "HOW did they discover all this? Untill then I will lovingly call it "Voo-doo engineering", because as advanced as it is, the nailhead didn't happen by luck. I just know there must have been lots of chickens and goats sacrificed to make the nailhead what it is today!:moonu: Erik
This is long but this is how I see it hopefully I don't screw it up too much... The nodules are intentional for sure (Proof is in those SAE papers talked about ealier) as best I can figure they are what the aerodynamics world calls "vortex generators" (VG's for short) In a nutshell they help air "bend" around curves (I know sounds like voodoo). In the case of a wet manifold they also help fuel (which can get "slung" out of the mixture onto the port/runner walls) shear back off of the port wall and back into the air/fuel mixture. Just read up on your fluid dynamics and Aerodynamics to find all sorts of info about this. It sounds magical but it's pure physics. I find it very plausible they would have learned this stuff from aerodynamics (think Jet research) discoveries of the day... A vortex or turbulence generator is any sort of protrusion, bump or sharp edge, that excites the boundary layer (no way I'm trying to explain that one). They wanted to tune for Max torque at street RPM's so they needed a long runner and intake port The long runner gains more low RPM torque, because it "tunes" the power band lower via increased "inertial ramming" at lower RPM's than with a shorter (or wider in cross section) runner/port. Inertial ramming is when air that wants to slow down at the low lift valve opening (due to the piston slowing down torwards BDC and the small valve opening), is litterally RAMMED into the cylinder by air that has high velocity "momentum" and is already traveling down the runner. High velocity Air also then slams into the closed valve and "reflects" (like a ripple of water) back up the port/runner and potentially into another opening valve. I say potentially because that's a whole 'nother discussion (Helmholtz resonance tuning) and might not be a part of the nailhead design (then again it might be). But before you go "oh yeah that's a whole different ball game, that's science fiction by 1950's standards...." Well Helmholtz the scientist who understood this died in the 1890's! So again, it's not voodoo, its not even modern science p Incidentally these effects are basically the opposite cousin to the well known "exhaust scavenging" effect that everyone knows about using long tube headers to achieve. Notice the theme long tubes, and long port/intake runners? The better "tuned" the length is the more optimal the result. So to get a long runner they made it curve because obviously the way to fit the longest runner under the carb and hood; Is to put curves in it. Buick didn't want chrome stacks poking out of the hood of their luxury cars!... but they wanted what velocity stacks give an engine... long tuned runners and high velocity. Now the PROBLEM with a long runner is fuel likes to hit the walls and collect and form rivulets and pools especially on "slow" areas of a port (like eddies in a river). I expect that they fixed the fuel pooling and loss of velocity at critical points with turbulence generating irregularities. Strong swirl also promotes keeping fuel in suspension down a long intake manifold and head port, and into the chamber. In the chamber at low RPM's the amount of time between valve closing and spark is sufficient for fuel to fall out of suspension and pool and puddle on the chamber wall and especially in the ring land volume... where it wont provide any useful combustion. Big time swirl keeps this low RPM mixture in suspension. The exhaust has sharp bends, and VG's in it would presumably be to help keep velocities high around upcoming curves. They knew what they were doing, as hard as it may be to believe 40 years later.
