Interesting head modification

Discussion in ''Da Nailhead' started by wkillgs, Sep 6, 2008.

  1. ahhh65riv

    ahhh65riv Well-Known Member

    Yup. I missed it. There is a lot to absorb in this thread. Not sure how I missed that. But then again in Shurkeys defense he also says (if you read further):

    Simon, You know you are twisting around what I said about torque! You are confusing what I said "MORE torqe" for "LOW END torque" The object is to not only increase the torque, but do so over a longer RPM range- Not JUST the low end torque the nailhead is famous for. Lets see the same numbers attained with a single 4bbl manifold! You cant use Teds comparison as a good example as he explained why. And you cant take say an awful-hauser 2x4 and compare it to a single 4 either. Now admittedly there are modifications that can be done to a single 4 to make some improvements. I dont think I need to restate the Stock torque and horspower ratings are for dual quads. Besides that is what is correct for my Super Wildcat motor.

    Since we are talking about runner length, there is also an argument to be made for non-progressive linkage (and a difference in performance)- two carbs running together in perfect synchonicity just the same as you would a single carb, only more CFM feeding each cyllinder more directly and evenly. To illustrate further: If longer runners are supposed to typicaly increase torque, why do intake spacers hurt performance on a nailhead?
  2. Schurkey

    Schurkey Silver Level contributor

    No, I used the term "laughable" to describe the RESULTS, not the technology used to generate them. AND, I recognize that those results have been tempered by the passage of ~5 decades of design improvements; I also quoted the 1953 SAE paper where Buick claimed that the original Nailhead was in fact the smallest and lightest engine in it's power class when introduced. When introduced, it was a milestone. But, even before production ended, it was obvious that certain design choices had proven to be less than optimum. Specifically, the thing needed a rompety camshaft to attempt to make up for NOT ENOUGH VALVE/PORT area. Which, by the way, even Buick admits--in the SAE design paper for the '67 big block.

    Thanks. Appreciated.
  3. bob k. mando

    bob k. mando Well-Known Member

    because I'm getting ganged up on here in this Nailhead forum for arguing that the Nailhead wasn't "laughable"

    no, you're "getting ganged up on" because you're trying to compare apples to oranges.

    most of us are trying to get you to understand the difference between Gross and Net power ratings. you keep trying to compare factory ratings from 20 years apart while ignoring the intervening advances in technology and then say it's only a ~5% difference. compare like tech to like tech at the actual dividing line ( 1971-72 ) and the story is completely different.

    the simple fact of the matter is, that if you take any 20 year span in IC engine development, the newer engines are going to more efficient than the older ones. the only thing that throws a monkey wrench in that is the emissions crap that got put on in the 70's. and i would hate to see what a Nailhead would perform like saddled with cats and AIR passages and all the rest.

    Schurkey may have gone a little over-board using "laughable", but if you're a Buick guy you've got to have a self-deprecating sense of humor. surely you've heard of a "Quadra-junk" carb?

    anywho, this is all completely off topic. we're all here because we like Buicks, right?

    and this thread is all about trying to improve on the 1950's technology of the Nailhead, right?

    [Rodney King]
    Can we all get along?
    [/Rodney King]
  4. doc

    doc Well-Known Member

    Dang, how did Doc get in on this cat fight?????:laugh: :laugh: Actually , if one were to compare a BONE STOCK 401 to a BONE STOCK 400 then you would have some thing to work with.... from experience , I would say that the nail would hold its own with the later engine..... now once the mods start the whole bet is off.... you never know just how a particular engine will react to what is done to it.... One time I took a 950 cfm carb off an 396 chevy engine and put it on my 401 and put my 850 cfm carb on the 396 chevy and both engines ran much better.....
    Both engines are torque monsters,,,, they should be built for peak torque at the lowest rpm and to live under ''heavy duty application'' as Buick put it...the 401 and 425 can usually hold thier own with any engine of comparable advertised horsepower, which is what the drag racing classes were set up on [hp to wt. ratio] 401s will hang inthere with 400s and 425s will stay with 430s..... the 455 is out of the nail heads class on cu. in. alone... all that I have ever said was just that,,,, and that a single carb manifold combo could be made to run better than most think,,,, and I will stick with that.... the dq set up SHOULD beat a single, all other factors being equal,,,, but I have seen several cars, mine included , where a single carb engine would run right with multiples and even beat some of them.....
    nuff said, lets have fun with our nailheads, they are unusual, they hold up good , and most people like them.... kind of like me......:bla: :laugh: :laugh:
  5. 87GN@Tahoe

    87GN@Tahoe Well-Known Member


    The 2.3 litre ford valves are 1.89" and 1.59" for intake and exhaust, respectively.:TU:
  6. 1bolt

    1bolt Active Member

    Generally speaking open spacers (squared hole kind) add plenum volume. In the case of spacers that match the throttle openings of a carb; they add to what is called a "secondary tuning" length, meaning its not adding to the "primary" port and runner length and is another chance to capitalize on inertia tuning. A "four hole" spacer is adding to this second tuning effect... Inertia rams air into the plenum at predictable RPM's based on cross sectional area.

    Anyway it's an excellent question, because it leads right into 2x4's. Secondary tuning effect is another reason dual quads move torque higher in the RPM range (and thus usually lose some total peak torque output). Eight barrels have much more combined cross section than 4... And larger cross section = lower velocity at lower RPM's. (note the word secondary here has nothing to do with the secondary throttle bores)

    There are several other reasons 2x4's tend to lose torque, carb signal is worse at lower RPM's, and also to fit two four barrels the runners tend to be shorter. Especially the outlying cylinders which are often longer than the inner ones, to reach the single carb style plenum.

    You're right you did say just torque and I put words in your mouth, for that I apologize.
  7. 66gsconv

    66gsconv nailhead apprentice

    Wow, all this being said it seems that the TQ is still there down low and gained a little plus for sure extended it out into the rpm range with the dyno results we have seen recently. Ya have to like that. Some of us want to look for more performance, some like it stock. ME, I want to do as Doc says and "Pounce on a vette like a duck on a bug". I still like that Doc:grin:
  8. doc

    doc Well-Known Member

    Welllll, Bob, old pard, you need to remember that when I was vette pouncing, there was no efi, no nitrus, no 5 speed transmissions, no turbo chargers, no overhead cam engines,,,,, and on , and on......:Smarty: :laugh: :laugh: :laugh: :laugh:
  9. 66gsconv

    66gsconv nailhead apprentice

    Thats ok Doc, It still sounds good:beer
  10. ahhh65riv

    ahhh65riv Well-Known Member

    ....Make that a "WILDCAT" Fight! :laugh: :laugh:
    Nobody is going to blows here and loosing teeth. Anyway...Who couldn't find you likeable anyways doc?

    Hey Wes... It's just now sinking in with me... Do you realize the size of engine the same valves are being used in relatively a modern engine as compared to the 401/425 does? A 2.3 LITRE?!?!?!?! :Dou:
  11. telriv

    telriv Well-Known Member

    I feel compelled to stick my 2c worth in this discussion for whatever it may be worth. Since I'm the one that started this little instigation on cutting off the flange with "Rotted Honda" I have to butt in. Going back through years worth of pictures & being pretty much computer illiterate, trying to enlarge these pictures & looking for any little details I could find, I found that one of our heroes, "Max B." He was making power up to & past 7K RPM's. How did he do it????? One of the reasons I'm sure is he relied on the "Nails" torque capabilities, but he also needed RPM's. When the Hi-Revving, Hi HP cars were going around corners & having to shift multiple gears to bring them back into their HP ranges Max probably kept his cars in Hi gear & without wasting precious time shifting gears the torque pulled him through. Even Carroll Shelby stated on a show awhile back about how he blow up a trans. that Max just got installed in the car from a salvage yard, "Man that thing had TORQUE"!!!! I keep saying how an engine (not motor) makes HP. It's all about passing air!!!!! Density=AIR/AIR=RPM's/RPM's=HP. It's that simple.
    I'm NOT an engineer or a designer or a scientist or any of those other things. What I am is an idea kind of guy. I have an idea & start asking many questions to those who have much more knowledge about certain things than myself. We NEED to get MORE AIR!!!!!. How can this be accomplished???? Through "Rocker" ratio. It's the only way!!!!! A cam WON'T do it. It will help but it's still lacking. Even on Erik's "Nail" with the cam he went with there was still a 13 or so HP improvement. On our engine anytime they were added it was almost always 20HP. On my stocker '64 Riv. it was an astounding 26.6HP & 15.1ft. lbs. of torque. This was to the REAR WHEELS!!!!! The dyno operator flipped out as he had watched me install & adjust them & know I did NOTHING else. He had NEVER seen just by adding "Rocker Arms" such an increase!!!! Just by adding "Rocker Arms" to see a 10HP improvement is something. Ask around many will say the same thing. I've talked with & worked somewhat with Greg. I have talked extensively with Mike Lewis & Mike Attwood. Have talked & worked with Steve Magnotti. Have sent pieces of head to Germany to pick the brain of a so-called "Volumetric Efficiency/Combustion Expert" to pick his brain & get ideas. This is where we stand at today with all these ideas running around. It's nothing but GOOD & that helps us in our quest to make "Our NailHead A Better NailHead. On all the engines I've ever heard run that are trying to make as much HP as possible, either on the track, dyno or wherever, they mostly all did the same thing. The engine stopped making RPM's at 5800 or so. Why is this????? It's all about passing AIR!!!!! No matter what cam. No matter what induction system. No matter what ignition advance curve. It could only pass so much AIR!!!! The heads are at fault. The intake manifold is at fault. Most cams are at fault. They will only flow so much & that's it. Get more AIR to flow & good things can happen. Look at what Mike A. was able to accomplish with manifolds. Even though the heads could flow decent numbers there were NO manifolds that could keep up with the flow, other than the Weber manifolds that Max Produced & are being re-produced today. But, even the Weber manifolds have some restrictions. On the last engine we dyno'd we had the same results, at 5800 it was over & fell like a rock at 5900. We maxed out just like everyone else, with about 450HP. More "Rocker" dyno testing. I absolutely wanted to make sure that at RPM's above 6000 the pushrods would not lose contact or jump out of the adjusting screws just incase someone missed a shift. We took it to 6400 or so 4-5 times & pulled the covers & checked adjustments & took the "Rockers" off for inspection. All appeared OK. The next was 6700-6800 the same 4-5 times. Again, everything checked OK. Next was the last series of pulls at 7100 a few times. We didn't want to go any higher for many reasons. Again, all was OK!!!!! What we didn't notice, we we started looking at numbers the HP hadn't fallen off more than 30. So at 7100 we were still making 420HP. Never did find the drop-off point because the bottom end wasn't built for that kind of RPM's. What it DID PROVE, I WANT MORE AIR!!!!!! Bob W. 66GSCONV, cut off flanges are real numbers, not a mistake. We have gone over this many times. Mike A. also did a test with a cut off flange. He didn't come up with the same numbers as Bob W, but then again he had already done some port work to that one particular port. Bob W. came up with the same results. Porting that port lost some low lift flow, from 112 to 108 at .100". Somewhat the same as Mike A. Looking at all those pictures as time went on you could see a change in the angle of the injectors & that's when Max really started to COOK!!!!! The "Pent Roof" combustion chamber DOES have quench built-in. In '53 they did NOT & ran into major detonation problems big time. They solved that later on in '55 or '56 & on all the '57-'66 heads. What's old is NEW AGAIN!!!!! Many of our modern Hi-performance cars have "Pent Roof" combustion chambers. This allows for multiple valves & able to get away with higher compression on the quality of today's fuel without detonation. Of course they also benefit from today's technology with computers, knock sensors, etc. But, it's real. Pent Roof works. A "Semi-Hemi" so to say. So where do we go from here???? Keep the discussions going. Nothing but good can come from it.
    It's been proven on the dyno that the intake spacers are only good for raising manifolds to clear linkages & such. In theory increasing port volume should work. We lost 10HP & 15lbs. when a 1" spacer was added. So much for increasing port volume!!! Having my carb. (Holley 750DP) using a hat on the carb. the engine used about 590 or so CFM's. Using a home made tunnel ram with 2/660 Holley vacuum secondary carbs. the engine used 622 CFM's. Now this wasn't one of those tall tunnel rams. It was kinda short & was made more for looks more than anything else. What it DID do was have a very poor vacuum single though the venturie's. To get the fuel to start flowing we had to raise the float levels 1/2 turn above the fuel sight glasses. Now with 2/750 Edelbrock's the engine used about 615 CFM's. Overall torque & HP output were highest with this set-up. Holding the secondary air flaps wide open did NOTHING for gaining, or subtracting CFM's, HP or Torque. It all remained the same. One of the things I can say for sure is that my single 4 was the most forgiving & more widely acceptable all around performance package. (Wish we had available a 950HP or something similar for testing) It mostly didn't much care where timing was, within reason, & HP & torque were close overall. On my mostly stock, low compression Riv. my "Rockers" & at about 4400lbs. has run a best of 13.902ET@98MPH. It would have been great if we had available to us a properly modified single 4 manifold as we know more now as what needs to be done. And a 950 HP carb. or somewhat. I can ONLY HOPE that Eelco gets that single 4 manifold done before we start on this next series of dyno testing on the "Latest" build that is being done NOW!!!!. It's also been proven that even though the larger 1.94" intake valves may flow overall more, at low lifts the numbers are much worse even on ported heads than stock heads. There is just too much combustion chamber wall which blocks the incoming fuel/air mixture. Now open up the area & compression drops dramatically. Mike A. has stated that a stock "Nail" intake port will flow about 4000 RPM's worth of swirl on an un-ported head. Now do some port work to that intake port & it drops to about 3200 RPM's. Now, to put this into perspective. The best Chevy 23* heads have about 2300 RPM's of swirl. So, we haven't lost alot. Swirl is like if your flushing a toilet. The air/fuel mixture is doing somewhat the same. So, we need to keep as much of this swirl as possible while also trying to keep the AIR numbers up. Many talk about fast burn technology. The "Nail" has had it since the days of the straight 8. Nothing NEW to Buick. Maybe everyone else. Look at when Buick was trying to design better cylinder heads. 1st. it was aluminum then around the end of '60, beginning of '61 they came out with their D-Port/Big Port heads. In the quest to make the port as large as possible not only did they raise the roof considerably they also dropped the floor. What this did was a larger port that flows about 10% less than a stock port. It's all about velocity. Buick, again, way ahead of their time. Chrysler made the same mistake on their "W" heads, but this was '69-'70.
    I could go on for days, but I need to get some things done around the house.
    Keep the discussions & ideas coming. The more that are involved that have a passion the more that can be accomplished.
  12. bob k. mando

    bob k. mando Well-Known Member

    I found that one of our heroes, "Max B." He was making power up to & past 7K RPM's.

    yeah, if you can turn 7 grand you're going to make hp.

    wasn't Smokey Yunick supposed to have done some silly stuff to a Nailhead as well?
  13. telriv

    telriv Well-Known Member

    Yes, a stock appearing, supposedly 600HP "Nail". I think it's home right now is at Garlitis's museum.
  14. 87GN@Tahoe

    87GN@Tahoe Well-Known Member


    "You can have all the soda you want, in one minute, BUT you can only drink it through this swizzle stick."

    If only they left us a little more space:blast:
  15. Well-Known Member

    I haven't read all of this thread, but as to the 3 1/4" crank "stabilizing" the block from flexing...well Shurkey it's not a myth!...that's what engine design honcho Cliff Studecker said a couple of years ago when he visited JW's shop and gave a talk about the 'old days' at Buick. They had tried a 3" and had breakage problems-
  16. Schurkey

    Schurkey Silver Level contributor

    Yup, the three-inch journal experimental cranks broke. Doesn't mean that the crank broke because it couldn't stabilize the block enough, though.
  17. doc

    doc Well-Known Member

    It broke because it was made of cast iron.... not forged steel.... big difference.... cast iron is not as tough as forged steel....
    engines with forged steel rods and cranks live better than engines with cast iron cranks and mallable iron rods......
  18. D-Con

    D-Con Kills Rats and Mice

    There are plenty of cast cranks with much smaller mains that don't break at that power level. And the cranks are not "cast iron" in the true sense of the word. they are armasteel or nodular iron.

    For some reason I want to beliee what the design engineers said. I highly doubt they were so ignorant to only speculate on the cause of such an issue.
  19. Well-Known Member

    Well Cliff was Denney Manner's boss-that's what I heard him say. There were other board members in attendance and some of us talked about it later. He had some fun stories about blasting around the highways with 'real world' testing-I think generally between Michigan and the Arizona desert proving grounds-
  20. tmcclu

    tmcclu Well-Known Member

    I remember Cliff talking about a $200,000 dollar mistake he had to tell his boss about, some real big bucks in the early to mid 60's! I think that was about the main journal diameter they were going to use on the 400-430-455 engines. I wonder how much money Buick would have saved by modifing the Nailhead for higher flow heads and a BOP bellhousing and keeping the good oiling system and forged internals?!

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