% Golden porting rules - part 4 of rule #1
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- เผยแพร่เมื่อ 11 ม.ค. 2023
- In this, episode 68 of PowerTec 10, DV imparts the sort of porting tech you will need if you want to graduate to the highest aspirations in the world of cylinder head technology. Best yet it is all laid out in DV's usual easy to understand manner. Pro or no you will learn at least 5 moves to make more poweer from whatever cylinder heads you may have. And by-the-way very little of what DV divulges here is common knowledge so if you are a racer or engine builder you can get one up on the competition!
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With all the books and seminars to consider, this series will be your legacy DV. I've learned more in the last 2 years than the previous 40 . Big thanks to DV Terry and Andy
Lol
Thanks David this is fantastic information for those who have the ability to comprehend it.. Many don’t have that ability..
“Give me a few minutes of your time and I will give you the benefits of over 60 years of building race winning engines”. I think you should lead with this every time. Solid intro.
This guy knows more than Einstein. Seriously. How would you all love to work with him like forever. I don't give it freely but you have my utmost respect.
Totally agree 😅 I have learnt sooo much in just a few videos and I am not even an engine builder 😮
So much information to contemplate, I'll watch this episode again tomorrow. The material is very well presented, you're a fantastic educator David, cheers for sharing!
what DV is saying about the valve seat mod is dead on. I read his books years ago and applied his knowledge (the guy who did the machine work laughed at it until he seen how well it worked) and my 305 Chevy put a whole lot of cars in Stock Eliminator on the trailer. I used to be a critic of DV until I realized I owed 75% of my success to the knowledge I gained reading his books. These videos are his legacy and to you fine Sir I stand and applaud you on your success and thank you kindly for being so humble while youre doing it.
Please do the world a favor and live to be 200, David!
All can do is change the oil but I can’t stop watching. Thanks for your time
Dear Sir, please accept my best respect. Your videos are absolutely brilliant!!! A lot of specific information told and explained with a normal human words - that is really somethig very special. Thanks a lot. Waiting for your next videos.
This is an absolute GOLD MINE
If your a gear head, you should thank this man and SUBSCRIBE
Another great episode David & thank you for doing so, and my friend so sorry for you & your family over Jessica my condolences
Sure wish you would talk more about 4 valve heads (instead of these old gas guzzler v8 heads), and POLYQUADDING! I would LOVE to hear more about; how you determine the proper intake to exhaust valve ratio with your formula, and how to determine proper primary header length!
These old “gas guzzlers” as you call them absolutely rule and dominate the high performance market of all motor sports , which is what David is so talented and knowledgeable with!
This is the episode I've been waiting for.
Thank you!
May God bless you 🙏🙏 thanks for your share great knowledge. To get this information must a lot of testing and experimental.. thanks.. fan from Malaysia 👍👍👌👌
I'm porting a set of double hump heads and you've helped me expand my knowledge of what to get the most out of these heads. Thank you David
There was so many understandable tips in that video I will watch it a few times.
Thanks for sharing your immense practical experience and supporting technical explanations. More information is provided in each episode than any other video I've ever found. I remember reading your technical articles in various motor enthusiast magazines back in the seventies. So glad that you are still sharing your profound wisdom. Thank you, Sir.
For me this episode was PURE GOLD!!! Can't wait for next installment. I think you forgot to go back and elaborate on the conformation groove developement. Would you please include cam spec requirements that correspond to to the seat angle/flow changes. THANK YOU!!!
I really love that finally, someone has combined plus explained science/physics with the process of porting heads. And the fact that AIRFLOW like that in aviation (Laminar Flow wings P51, Bernoulli's principle ect) is applicable to engine head ports. And just as too high a angle of attack causes the airflow to detach causing a stall, so too how airflow on the short side radius detaches and requires attention to fix. Along with David's book on head porting I have purchased, these videos further help my understanding of how airflow and correct porting improves even a stock head to rival a purpose-designed aftermarket head like AFR. I am hoping to embark on my first head porting exercise on a set of Australian HOLDEN HQ 308 heads, 123cc intake volume similar to a standard FORD 302, L34 1.94 inch intake and 1.49 standard exhaust. I now understand how important a good 3 angle valve job is for low lift flow, seat angle, blending the seat, setting the THROAT to around 88-91% of intake diameter and port bias. THANK YOU for your very imformative videos. I wonder DAVID if you have or could do a video that shows the porting process using a grinder on a standard head which helps illustrate all your Golden Rules???? It would certainly help a novice/first-time porter like me see exactly how to employ your science and concepts in a real-world example. EG How I could use your Speed Bump theory when porting my 308 Holden Heads???? Look forward to the next video.
All the flow past the carb and boosters is turbulent. The air in the intake port is stationary about 75% of the time, with the suspended droplets moving relative to the still air, and puddling. The short turn radius always has a detached flow and turbulence. Search for flow testing with a ball on a stick to find intake restrictions.
Best wishes from Florida.
Thank you. Learned a lot
Always great content thanks David
Hi David. Loving this series! So much info and so much for me to learn. Thankyou!
I'm just preparing to do my first port and polish job on a set of late model hemi heads. I've been doing research on the different processes and methods out there. 2 days ago a good friend sent me an older video of David's and I've been on a binge. I've learned more from this one series of video than I have in over a month of researching hours daily.
Hell yeah Billy!!!!
Back in the day, when I was doing cylinder heads, my personal strategy / process in doing ports was to begin with the 30 degree top / transition cut, into the chamber, to establish the eventual seat heights and the chamber roof to wall radius, to the cylinder bore line, working through the seat angles into the throat.
My theory was that the throat, seat angles, and top cut into the chamber roof and wall, was a given, and dictated the architecture / modifications required of the ports.
Seemed bass-achward to some, but worked well for me, and established fixed geometry to structure the port on from where the flow eventually was dictated by.
I'd love to see you get a LT-6 to look over, and examine, piece by piece, 5.5L DOHC V8, 32valves, 180° crank!
Another informative video. I wish I had seen this years ago. Thanks for sharing your experience with us! I’ll keep watching! 👍
David, I would love to hear your port analysis of the late-model Hemi cylinder heads, known as the "Eagle" heads. Port biasing would appear to be similar to SBC but, to me, seems like it's night and day different than SBC ports....due to the manifold-to-valve angles. The Eagles counterparts, the "Apache" heads, flow better, especially on the exhaust side. You touched on the late-model hemi's in this video, regarding their valves 18-20* backsides. This is due, again, to the angle of air entry into the bowl area.
You are the man David 👍
The Ford FE uses a great deal of these properties in their ports. The port crosses to the inside in the way that the 4 fronts angle forward and the 4 rear angle back, the wide side is the cross over the SSR to the center of the bore and the twist fills the center of the bores and the bowls are shaped with the high side of the bowl when cut across shows more area in the upper bowl on the center side of the bore with more bowl capacity than on the wall side. This makes them easy to port for excellent power and torque. I have studied cutaways of these ports and I can see why they stayed with the Hemi engine for all of those years in competition and even took on Enzo on the most demanding race course and longest and most demanding of all the world.
Thank you David for giving us your knowledge!!! 🎉
I love these videos. They help me get better.
Incredible depth of knowledge.
Thank you David!
Just awesome David. So glad to see you continuing with this series. Just ordered another one of your books, and I'm looking forward to it arriving. Regards Greg
Awesome stuff as usual DV , Keep up the great work 👍👍
i enjoy all your vids ! thanks so much for shareing all your experence with all of us ! david n.
Holy smokes that was awesome thank you so much for the info I will review this again and again
Kudos, I for one greatly appreciate and admire your reasearch
The buccaneer wing vortex generators did a similar thing. High angle of attack stall prevention
Thank you David, it’s starting to become clearer after watching multiple times.
Thank you for your teachings blessings to you and yours david
great viedeo for cylinder hear porting rule nr 1.
also great info for classic bmc engine tuners
Likely the best summation of valve/flow nuances ever.
Good stuff thank u DV I've learned a ton from u thank u sir !
Keep up the excellent content .
A true visionary !!! There is nothing new under the sun !!!
Thanks DV for your expertise and scientific approach to the world of performance.
Wonderful presentation,it's a treat to learn from your vast knowledge.
David
Thank you for the in depth information on valve shapes and seat angles. I would really like to try using the valve you developed for the mini on a chevy 6, along with a refined lump port with the speed bump shape. Also, the information on confirmation grooves on the valve face and use of the 30 degree seat angle is very informative. I considered using a 30 degree seat when I read your book on how to port sbc heads. I wondered about seat longevity for use in a daily driven sbc. I also had seen it in the how to build a max performance small block chevy on a budget. I am glued to this series of videos, I want to add that you are a very inspirational person to continue offering your hard earned knowledge to the public for free. Not too many professional, or so called professionals are willing to do this. Again, I want to say thank you to you and all involved with the production of these videos.
Can you help explain the anti-reversion groove at 11:00 (Conformation Groove) and it's dimensions if on a 1.94 valve and exactly how it's supposed to work ?
I don't get how it works.
Awesome keep them coming
DV, I've got your books and have studied all these examples, but thanks so much for the added details and explanations in your excellent videos....it all helps!
You are one damn fine man...I very much appreciate everything you do...your knowledge is incredible and your books & videos are tops...
Great Thought Provoking content as always ,the speed bump you talk about, the chevy inline 6 guys have been doing this I believe since the late 60s they call it a lump port hopefully I can get to another one of your seminars when you come back to Australia 🇦🇺 🍻👍
The Ford FE from 58 to 65 and 66 PI and the Cobra Jet is a great example of a sophisticated bias, short side, and the speed bump. Ford built long range bombers and learned a great deal about building V engines in WWII.
Lump port 6 cylinder back early 70s with J B weld
@@thepoopsoup How well did the JB Weld hold? There isn't any way to anchor it to the port.
@@briantayes2418 Shot peened the port never ever had one come loose.
Hi David..in 1964 as a 19year old I ported and had skimmed a mini 850 head on my kitchen table using you're info from a library book "Porting A series heads" I think. My tools were a diy electric drill and a pack of Stones. Worked well and my minivan felt the benefit. Still dream of clover leaf combustion chambers! I see we are both ageing like fine wine. Kind regards.
production quality on this video is a big improvement over previous ones.
some of the best descriptions of your principals so far.
Could you go more into the use or creation of this "speed bump" in the port floor? sounds fascinating.
At about 08:20, you say that the area improvement of the 30 deg seat over the 45 decays rapidly with increasing lift, becoming minimal over 0.250".
The gap between the two black lines representing that difference shows the greatest difference at over 0.600 lift, and not much difference at 0.250....maybe wrong chart, or I am misreading?
I borrowed &read "Tuning BL's A series engine " in the early '90s...was able to find a copy 10 or so years ago. I'm not a British car guy, but enjoyed it and learned. ( I'm a CV carb fan due to a motorcycle background).
Eventually ended up, I think, with all of your books minus one on sbc valvetrains. Great information that I enjoy reading.
I recommend them, even if they don't seem to apply to a person's particular interest...like the "A series " book- any engine guy can learn something from it. And the Holley specific book is worth reading even if Holleys aren't your cup of tea. The one on porting is excellent, too.
They all encourage thinking about details rather than bolting together parts on a list...things that can be applied to any engine.
Time to fix those one angle valve seats on your snowblower!
That graph covers a lift range from 0.00" to 0.080" it is just illustrating area as the valve is coming off the seat. DV go's into more detail on this on page 74 of his book "How to build and modify Chevrolet cylinder heads"
I'ts just getting better and better. Thanx👍
Great video, very informative.
Thank you for making these
Very good and Detail Informationen thanks a Lot for sharing so much know how.
Awesome can't quite get it all but quite informative, thanks for sharing, all the best to you and your loved ones
This might sound weird David, but I just got some 60/40 Kevlar/carbon fibre and it looks just like your shirt! 😅 Lol so I love your shirt. This video ends just where I was getting more interested about the plane analogy, and using the teardrop shape of the engine cowling to better improve flow/stiction on the inside turn of the port. Hope you expand on this in future videos, great work 😅
outstanding information Thanks
🔔😎
Being an old guy like you DV, with an aviation career... Let me address the Waco cowling.
The speed bumps MIGHT act as vortex generators but as I understand it the intent of the original design was to allow the rest of the cowling to be more pointed into the relative wind. This @ 3" reduction of diameter does allow for less drag and more speed per thrust. We usually called these "speed cowls".
Now I'd like to see one in a smoke tunnel. 😁🤔
The plane is pronounced like "walk oh" as I understand it. I appreciate the wealth of information DV. Thanks! I'd be interested to see more on exactly how you grooved those valves, and etc with that part of it.
Luv the old stories racing the English cars. My ole mum had a mini and later a avenger.
Also the sbc rockers do not line up centered on the valve stem which may cause some wobble, we use isky adjustable guide plates to correct it.
i thought of this bump a week ago. I also thought of placing a blade too direct the air in the port floor.I also thought reverse golf ball (raised) bumps on the floor would aid the turn
I give this video % stars out of %. Great info!
David Vizard:
This is probable the best episode because it is the most clear one.
Hopefully this video gets a continuation with more actual foto's or film of details like these airplane 'bumps' etc.
Please do continue.
ps: could you add metric sizes too? Thank you.
The MINI classic head seems to have 2 inlet ports splitting up over 4 valves. The exhaust pots are 1 - 2/3 together - 4 = 3. All, the IN and OUT are on one side.
That's absolutely different than the FIAT 600/850/903/ to 1050 OHV head. That one has an intergrated inlet manifold molded into the head on one site and exhaust on the other side of the head.
And there it come: the angle of the valves are only ideal on the exhaust side! In other words: the angle of the inlet valves are not positioned 90 degrees but are laying 'flat'. So taking away material here seems not possible due to this angle and the big 'room' of the combined inlet ports alias molded in inlet manifold.
So creating a 'bowl' here is not possible.
Speed of the fuel is only between carb and head in the so called spacer.
Great content, thank you very much
Personally I wish more 4 valve stuff, especially on valve and valve seat.
I second that! My take from it is the 1/4 D happens much sooner with the smaller valves as there's 2 smaller valves vs one. Basically shifts all those charts to a lower lift. Hopefully that's correct.
1/4D is exactly the same, regardless of how many valves you have. 25% (1/4) will always be 25%. You can have the same Lift=1/4*D for different engines, one with 1 intake valve and the other with 2. I'll explain myself better. Take a valve of 50mm (2in diameter if your in the imperial system), 1/4*D is 12.5mm (0.500 thousands inch lift). Now take 2 valves of 25mm and apply the Lift=1/4*D rule (it comes out at 0.250in each), and now sum them up and you end up with the same total 0.500thousands inch Lift. Be it that for the two motors, one with 1 the other with 2 intake valves, at 0.500in Lift the Area presented to the cylinder is exactly the same. @@bobbyhaskell2048
Thankyou so much for the info David! Being slightly vision impaired has meant it's hard for me to read your book, so I really appreciate all the TH-cam content you are putting out!
I have a question, how should I be adjusting my cam profiles for head compressing n and flow?
Some older GM heads have a vane in the intake port, which could be whittled down to the "speed bump" shape DV described. Might be worth a try.
Are you referring to the port floor?84 My 2.8L v6 884 heads have that vane on the floor. I narrowed those down a little and kept the rounded shape. Result was mileage up 1mpg to 25mpg@70mph and much better throttle response through the powerband. Mostly felt in mid top end. 2800rpm up.
Thank you for this. I’m understanding the text which I have been reading from you for 35 years far better. I’m watching with the text books in front of me. Especially this five golden rules. I’m faced with a challenge that you’re damn right I’m up for. But it’s not gonna be easy. I know I have the right cam. But the ports on the heads.. You know how if you are driving on the freeway and you go around the long sweeping turns that if you’re going 80 mph it’s no big deal. These suckers are like if you’re going 80 mph and turn into your driveway. The $40 flowbench is going to have to get me through. But just hogging these out is just not the approach.
With a more one single stage seat, the breaking of that seal will also be more abrupt.
Hence creating a much more singular one stage to the breaking of a vacuum.
Defiantly could be an advantage.
Air speeds are off the charts because the pressure change.
Too me thats one of the real drivers we neglect.
Across 3-5 valve seat angles(staggered) the pressure release is over a larger surface area/ longer time.
refining the breaking of the valve seat seal is AAA1 important.
Next is the piston to bore edge turbulence.
: )
🔔😎
In the aviaion business for 50+ years the proper pronunciation of WACO for the airplanes is.... WAH-koe.
The city in Texas is WAY-koe. 😁
40 yrs ago I lived in Waco and sometimes flew a Waco.
**
And the Willys jeeps are not Willeeeez but WILLIS, as that's how Mr. Willys pronounced his name. 😆
I was thinking that as well but wasn't sure. Funny you should meantion the "Willis" jeep. I had a met a guy who was a enthusiasts of them. He kept referring to them that way. I thought to myself is this guy confused or have I been saying it wrong all along 😂.
The bump in your port diagram is pointing in the opposite direction compared to its orientation on the airplane.
O lado mais alto da lombada tem de estar próximo da curva.
So from this video, David, I'm taking away in addition to your sbc 5/7 intake manifold knife, one could also treat the 5 and 7 intake ports in the head differently in porting to accentuate the system as a whole
I lent your sbc cylinder head book out to a buddy. He thumbed through and liked it enough to let his uncle read through it
I been working with the fins "speed bumps" since the 1990's I have used them successfully in 426 Hemi Super Stock heads and also 400 wedge heads I call them my "vortex generators"...
Thanks!
I never touch ports, valves etc, i always bought the cheapest of what i need and want, these things come good enough for me from the factory, for the daily driving(although i was always a professional SPEEDER lol, ...still am at 70); but i still watched 1 or 2 videos... FF a bit;
(the gentleman has all the time in the world, it seems, but we, on this side, don't, usually)
Thank you
Good video; lots of content
About that plane at the 13:38 mark... Although the town in Texas is pronounced with a hard 'A', like in 'bacon', I've always heard that aircraft pronounced with a soft A', like in 'taco'
Hmmm... now lunch is sounding good - think I'm off to La Huerta to see if they have tacos de cabeza!
The way of air is best perceived in nature.
I remember that yellow camaro. My step dad built it.
Genius. Period
🏁🏁🏁
Mr. Vizard, Im curious about your experiences or thoughts on the port "dimpling" that is commonly seen/used by some porting companies. There seems to be a lot of arguing about it, but no one have given proof if it "works" or not. I believe you would be the one person with the answer.
Are you able to do more on the Avenger engine? That's one interesting engine.
Yes here too. ive been rallying them for years in the past
You know nobody talks about the seat distortion when hot. Everyone tells you how important seat concentricincy is.
Air bumps are a funny thing. Placed AHEAD of the desired result, vs placed AFTER the desired result is a matter settled by which bump was smaller to get the desired result. Un the runner floor case, Grumpy Jenkins had a floor depression (removes more metal) whereas the addition of DV's speed bump is quite small amount of "metal", for stronger result. Yet, the "reduced CSA " concept to flow more would be that narrow upper runner zone ( more fill material). Suppose my point would be that a proper turtle- bump could improve short-side flow too, if that was desired. Overall DV GR#2 holds to let the air go where it wants: the far bowl wall to CYL. Oh yea, there is a bump-opportunity from Head--to-CYL on the strong Inhale path (AFTER the bowl, shortturn, and runner floor that may just "do it all", thus save effort on floor features. I think.
Does this apply to most of the SB Chevy heads? Thanks for the great videos.
David is so smart
What do you think about engraving small “cooling fins” on the intake port , along the exhaust side to try to cool that side of the seat, to help with the distortion of the seat?? If a semi rough intake port helps with atomization, as long as the grooves are small, they might actually help with evening out the temperature difference,and reduce the amount of distortion of the intake seat. Whadda you think???
Love the idea of the speed bump! Do you have to add material or cutting the shape ahead of the turn be enough?
Speed bumps for greater speed, never would have thought that.
Physics is fun
Hi David, has anyone ever experimented with a full radius/curve on the valve and valve seat as apossed to three flats? I know it would increase the suface area and the chances of it 'welding' itself through every cycle but would like to know if anyone has tried it and what difference, if any, in flow😅 loving your videos and keep up the good work please, cheers 😀 David
Your method effectively creates a vortex generator inside of the port. My guess is it allows the air to remain in a laminar state instead of creating turbulence going around the short side of the port, effectively "spinning" the air around the diameter of the port going past the valve into the cylinder, reducing the effects of inside curves. That's the only other way I can think of reducing turbulence besides having a longer or straighter port.
One good way that you can help build urgency in the sale is asking what are called consequence questions now that's called an n e p q l
G'day DV. Any chance of some old film or photos from your journalist days to do with your Cosworth beating RPM's? I'd be so happy to see some of the pics and or footage. Or if that's not possible it would be a great video series to reproduce some of that high performance engine build power for a popular TH-cam series. Keen to hear back and very privileged to be here and learn from you. Cheers mate 👍
Great videos Sir! BTW, The Waco aircraft is pronounced Whah-co
David, regarding the A series head, is there anything about porting that you'd like to add to "Tuning the A-series Engine" that you've learned since it was published?
That might make a nice case study video.
I have tried polyquading in naturally aspirated single cylinder engine for test , 175 percent increase in low end below 7500rpm after that power decreased drastically around 65 percent
another great tech video.