5 golden porting rules - #1

[@IOPOrt51]

I can not tell you how much I am enjoying your videos, the opportunity to experience "Data" rather than "tribal knowledge" and the experience of 60 something years is something we would all be foolish to ignore. I look forward to every video and have told all my gearhead friends about your site and never miss an opportunity to like them. Thank you and keep it coming. Please.

[@frankromero4048]

I started Drag Racing in 1967... David Vizard's books were my Bibles back then... I'm very glad to see that you're still at it... I'm 73 years old now...I'm still at it too... I've only been building High Performance Harley Engines for the last 20 years... I stopped building automotive, diesel and marine engines back then... CrazyHorse Speed Shop NJ

[@tayloralvidrez4342]

High performance Harley... That's an oxymoron

[@eddiesheeran5791]

This is literally a free engineering-level course in cylinder head flow dynamics. Thank you for making & sharing this!

[@TheDrAkira]

I took a full course on engine tunning for racing a few years ago and I'm proud to know that my professor explained to us the same as this great man here. This channel is Gold. So many people talking nonsense nowadays, but this man is great!

[@UrbanHarvesting]

Hands down the best book I have ever purchased, cover to cover gold. My 1st port job was after reading your book port & flow test the engine was a dirt speedway ford 6cyl 250ci crossflow for Australia. The car won everything it was entered into for 2 years on the same build until I built a competitor car motor, the 1st race they were both in 1 x new 1 x refreshed they ended up 0.3 apart over the finish line and 3/4 lap ahead of the field. I have always wanted to thank you for all the shared information you have learnt in your many decades of building/racing and shared with the greater racing/engineering community. I have recommended and quoted you many times since, only just found you today on KZbin. Wish you were in Australia I would gladly work for you as a learning experience Looking forward to the next videos in the series Thank you David for sharing

[@rodrigograss3580]

David, Thank you so much for sharing your knowledge. It is greatly, greatly appreciated. No amount of thanks would suffice I think, but rest assured i'll at least help share your insights with others.

[@fernandohood5542]

A Guru breaking it all down for you free of cost.

[@qoinsmartme1244]

Respect to those that share their acquired skills and knowledge, which most definitely includes you David, Thank you. Had to reply to the malicious keyboard warrior previously, who, I believe is stuck in a world of hate. In reply, today we have an exponential volume of knowledge, led by Dr Google, good bad and indifferent. However principles remain constant and are enduring. Remember over a century ago twin cams, multi valves etc were already being manufactured. In the US mass produced car engines didn't reach a hp per ci till mid 50's. The evolution of fuel, alloys, man made fibres, casting techniques, machining and most of all, in recent times, silicon (as in computing) have revolutionised our world including automotive engineering. I will put my faith in a human being that has honed (punn intended) his skills over half a century and is prepared to share them. Thanks again David.

[@mikedearman9630]

You wrote your first book 7 years before I was born!! Outstanding, love this. Like watching my old chemistry teacher talk about machining. Thank you!!

[@rondye9398]

Smoky Yunick claimed the point of greatest restriction is at the valve. So valve/seat angles and the 1 inch above the valve is where to find the power. Of couse much work has been done since he was in the game. I have great esteem for David Vizard and Smokey Yunick.

[@johnfairchild3421]

Smokey done. Almost genius work

[@exploranator]

Learning more than I knew existed for decades in head flow and porting!

[@ferrellvance5565]

what a great Wizard, I am a retired 71 years old, and just got inspired after watching this genius give us his lifelong experiences, I just tore my engine down, sent it to the machine shop for my first major rebuild and blueprinting I will be doing myself, thank you sir for all you do, the world could use more gentlemen like you!

[@martinfahrni5677]

Born in 68 I love your knowledge, churning these lectures like candy, probably never gonna build another small block again, but you are feeding my dreams

[@bravohomie]

It's never too late bro

[@TheFarCobra]

My friend Corky Bell once described David as the best combination of a genius and a practical man.

[@johnfairchild3421]

He is a Gearhead lol

[@billnlori3149]

Great info here. DV is a gold mine!!

[@captainsledge7554]

Usually I skip over old timers, because some of the guys I've met or watched haven't the slightest clue how things actually work. They just have their ideas and theories. That may have won at the local sportsdrome lol but in today's engines they are lost. "Too many wires blahhh" lol There's still old guys saying 305 heads on a 350 is the way to go. (It's not, you lose so much cfm flow in the runners it's crazy) Then u have those guys who say they tried vortec heads on a sbc. They're junk. I ask em which cast it was. They said it came off a 90 Chevy truck. 😂😂😂 bro that's swirl port. Worst possible head out there. They think the center bolt valve covers automatically mean vortec heads 😂😂 Anyways My point was... this old timer right here knows some shit and I like his channel already. Subscribed.

[@goodboyringo9716]

Hi David I just came across this video and found out about your daughter Jacque's passing. Once learning of your beautiful daughter, I need to give my condolences to you and your wife. I read about how she was an engine builder and what a great soul she had. So I just wanted to say that I feel your sadness for her. She is in good hands with our great Lord Jesus Christ !

[@michaeltruscott9443]

If only these shows were not available in the 80's man do I wish they had been what an incredible amount of dyno time you have outstanding job ol man

[@arealassassin]

They had these things called books back then; one read them, and applied the information gained to the problem. I have as many of the greats as I can get my hands on- Smokey Yunick, Phil Irving, David of course, Carroll Smith...etc. Nowadays people watch something on YT and consider themselves instant experts. This video does nothing more than reinforce the concepts David was writing about decades ago, as he says.

[@9psi]

Very interesting. Especially as back in the day we just used to just port match to the manifold and kid ourselves we were making more powa

[@timothyjudsontaylorofficia9786]

When a legend of performance speaks, it is wise to listen.

[@KJs581]

Wow, got so many of your books, the Mini one, and HP books "performance with economy" - from what, 40 years ago???? I learned so much from those books, and it helped so much. Good to see such a legend on here.

[@stephenrocque8458]

I saw your KZbin videos - excellent work ...I have some of your original books from the 1960s and 1970s Keep on going Mr. Vizard

[@josephrobinson8894]

I’ve been watching your videos this week and have learned so much, your teaching is so spot on. Thanks so much for your instructions 👍🏻👍🏻👍🏻

[@kylehill4887]

your a loved man David vizard many thousands.... we appreciate you and all you do

[@EdBoi18]

Pretty educational stuff here. My takeaway is that any work done further up in the port should probably be to provide enough of a straight shot to the valve to utilize more of the "shrouded" short side and reduce turbulent flow up until the air gets to the valve seat and beyond, at which point, inducing turbulence and mixture motion will hopefully even out any pockets of rich a/f mixture and contribute to a quicker/more complete burn.

[@DavidVizard]

Intake ports are totally turbulent from idle up. There is no getting rid of it!

[@turbotrana]

I am surprised David has only got 15000 subs. In a hundred years time this will be the only record of this type of knowledge.

[@vikenlink]

It won’t matter in a hundred years…. One of two things will happen. 1 …No more internal combustion engines will be in service due to technological advances and or 2- no human beings left alive to talk about it because we ported our heads out of existence over oil….destroying any chance of survival by killing our planet 🌎

[@vikenlink]

Sometimes it’s better not to make any comments…. Too many sensitive people out there trying to learn how to port cylinder heads. Fact is every cylinder head is different, every performance engine build is different. Porting cylinder heads is just the tip of the iceberg for horsepower and torque. What’s your compression ratio? What’s the displacement of your engine? Are you running headers and what size? Are you running a performance camshaft and what’s the duration? Are you running a aftermarket intake manifold… which one? Where do you want your power curve for 99% of the performance fans that drive street cars .You can port a cylinder head to perfection and then use the wrong size camshaft or wrong intake manifold because the one you bought looks cool…. But what ever you gained porting and contouring your intake and exhaust ports was lost because you used a bad combination like a sheet metal intake with short runners and a cam that wouldn’t idle below 1000 rpm’s . Great I got 650 hp peak at 7000 rpm’s. But lost 60 foot pounds of torque and 50 hp where I’d prefer to be enjoying it … 2000-6000rpm Headers without considering the primary diameter for your engine displacement and static compression ratio. Lots to consider when diving into a project.

[@theoldbigmoose]

Excellent CFD visualization David, thank you!

[@RichieCat4223]

I would like to have seen a before and after picture of that 91% valve seat done on an actual cylinder head to get a better understanding of the theory.

[@1967davethewave]

Excellent!!! I have been "amateur" porting for many years but have kept it simple as not to cause more harm than good. Having the exact contours and a base measurement to shoot for is a really big help in taking my porting to the next level.

[@carlosabreu922]

#1 of the 5 COMMANDMENTS from David Vizard's porting heads! A true Genius "Number$ don't lie, BS does and also walks (takes a hick)"

[@alessandroghizzo972]

Always the best resource for serious tech info

[@stealthynoodle2707]

I've had so many questions recently about 4-stroke engines after doing a fair bit of research on 2-stroke engines in terms of performance and flow efficiency, while it's definitely alot to take in this video delivered well beyond my expectations and already answered alot of questions I had regarding improving said efficiency and flow. Thank you so much for this, I cannot wait to learn more through your videos

[@landonthompson5604]

Thank you David for the information and direction to improve my knowledge and skills needed to be successful in creating a cylinder head that will improve the overall performance of my project engine. You're a lifesaver and I mean this sincerely, thank you!

[@donmilani129]

Excellent information and explanations what works and why, instead of just hogging out ports especially in a vortec style head

[@annebrown4337]

Thank you for the nice lesson.

[@thijs728]

This is owesome oldskool stuff presentation. Just love it

[@peterschofield739]

Dave, I did the rule 3 calculation of the weight of air in an average school gymnasium... i came up with 1.6228 tons.

[@jamesandannschmitt6835]

Thank you David.

[@lautburns4829]

Thanks again David. ✋🏻👍

[@flyingdebree3094]

Love how you explain things

[@ryanbackstrand]

Love these videos, but I always change the playback speed to 1.25x

[@d.thorpe2046]

I wish youtube would go above 2.0x sometimes.

[@tonymottram1396]

Thanks for the video I really appreciate your time in showing me this.

[@Tsxmichael]

Im very proud of my self to figure this out my self! And see how right i was on my project watching this video now 😌

[@nathanbopp6163]

Great to get this technical education on KZbin👨‍🎓🎓🎓🎓🎓👨‍🎓

[@edsmachine93]

Thank you David. I really appreciate these videos. Thank you for sharing your time and expertise. Have a good day Sir. Take care, Ed..

[@samupk]

I wish i would had this kind of info around 2004 when i was building CA18DET and RB26DETT engines in my carage shed :D Would have been much more than 408hp from the CA and hell of a lot more from the RB... Well, i guess today its more like plug and play tuning for youngsters with addon parts only.

[@Kryndon64]

I don't have access to proper tools so I wasn't comfortable with messing the the valve seats on my RB20DE Neo, but what I did do is polish the comb chambers up to 2000 grit completely smooth and also took off material off the short side to help with tumble. Additionally I smoothed out 95% of the entire intake plenum which should help a tiny bit as I did not like the casting on the inside. I just wish I had a proper dremel and bits so I could have gone deeper and more precise. Also lapped the valves which ended up really nice.

[@michaelosborne513]

Again thank you for videos God bless you sir.

[@KerbsideClassics]

Great channel old school tuning legend

[@SteveWright-oy8ky]

Thanks David for your tutorials as they are very informative .! I Have an issue with the LOUD MUSIC playing while trying to listen to you ! I have TINNITUS , ( ringing in the ear ) and between trying to hear you over the MUSIC and the EAR RINGING is extremely hard to do ! If you could cut the MUSIC VOLUMN by 50 % , it would be much better for anyone trying to concentrate on your talks . The content of your tutorials are far more important than the background music and that is why we're here listening to you ! Thank you again !

[@ElvinLeadfoot]

Harking back and watching once again..

[@anthonymilano691]

When porting the cylinder head one should note concentrating on having the highest port flow average rather than peak, and know that it’s just part of the equation

[@user-id9ft8qv4x]

Thanks for knowledge!

[@YerkitRacingChannel]

Thanks for sharing the illustrations! With the cfm from the cutouts in mind makes you wonder if it's worth touching the rest of the runner lol. Would be interesting to see something similar on a stock casting for comparison

[@bullitautorepairsmobile4989]

Are you the same David vizard of Mini Cooper fame, I bought your mini book years ago forgot the name,but I remwmber the lotos engine on a mini gearbox, I even moved my clocks t o put a 45 Weber on my mini 1275,reborded it out to 1330 if I remember correctly but the battery box in the dash good old days building my 1275 gt clubman .i remember now how to modify mini,by David Vizard ,definitely a new subscriber,

[@diesdasa]

Thank you David Vizard!

[@richardmoerke9329]

I can’t wait till then. That’s was a great job .

[@mikemoore5929]

David Vizard was th einspiration for my career in modifying cars and engines . I bought '' How to modify your Mini '' in the seventies . What alegend !

[@herseem]

I got his 'A' series engine book. It's encyclopaedic. I spent a fortune modifying my allegro estate, and it was all worth it

[@fraud3647]

Always learning something new when listen him unique knowledge how to modify ports, seats, valves and chamber. Probably he is one off the best headmaster what I know.

[@clarkmcmahan1595]

Sure wished you had finished by your explanation on areas of efficiencies of the seat .can't wait to see how this works out ..

[@bcbloc02]

I would love to see a series on home building flow benches. I am about to get a shop vac and a manometer and go to town testing!

[@billshiff2060]

Built several. If I did it again I'd consider a leaf blower or 2. The best is a roots blower.

[@spleno1]

Love the great information your making available for the public. You're being a true gentleman. Unfortunately when describing the seat angle, your hand was blocking all the important pick work you were demonstrating! Also we want more on polyquad heads. Who still drives boring old 2 valve heads?

[@raymondguzman5083]

Lmao i drive 2 valve heads and tons of other people do as well

[@freshkryp69]

Back in the 90's, when 'Roadsters' was the end all be all website/hub for performance companies it lead me to Vizard! He's a badass dude! I printed out all the 'Performance Professor' articles! Felt guilty I didnt have to pay for them! Best freebees ive ever got pertaining to race engine!~

[@BigEsGarage]

The minuet I saw the lightning I hit the subscribe button, like. This has to be good!!

[@danieldonahue3293]

Great science-based info ...thanks for posting !

[@jasonbirch1182]

Good info but I'd like to see what a non race prepped head does in that computational simulation and how much cleaning up the sharp edges from cast to machined accomplishes. Showing where a restriction in a fully prepped head is doesn't tell me much about the garbage I want to improve.

[@nathanbopp6163]

Sharp edges will crack easier than rounded edges.

[@alleyoop1234]

Have patience, I'm sure he'll get around to that stuff eventually!

[@garlandjones7709]

​@@nathanbopp6163he's not talking about shaping rough edges into a port. He's talking about casting flash and roughness in OEM ports and tracking improvement as you go on OEM stuff. Not improving already prepped heads

[@disolejunk]

Go until you hit water jackets...🤣🤣

[@fraud3647]

There is no any reason open port too much, velocity is King!

[@PhilipUnderwood-oy9tv]

I agree with you 100%

[@gregquinn6827]

Thanks a bundle sir! So many myths dispelled! So much data!

[@IronmanG74]

Point 3. 7 port heads. A massive weakness

[@notbuyingit8047]

I’d love to see what Mr Vizad would do to a Gen 5 LT1 head

[@user-cg1jg9mi5c]

great graphics from the Port Velocity at different lifts.

[@ebbonemint]

Well, I wish I’dve watched this before I spent 5 weekends porting and polishing my heads.

[@spyker_aileron]

So basically. High-ratio rockers and camshafts go first before i ever think about porting. Just get the valve out of the way of the air.

[@raffiki222]

David Vizard is on youtube!?!?! Thumbs up!

[@knickebien1966]

an interesting perspective

[@theblackhand6485]

@David Vizard: Could you make a 3D animation of the different radius's of the valve seats? Then it is more clear what you mean with the 92, 93, 88 radius along the valve seats. Thank you.

[@danmaycock9238]

Are you from that lil part of America where their accents mixed with Cornish?

[@TheMoghrabimahmoud]

Vizard the porting wizard ❤

[@yzScott]

Too bad I didn't find your stuff years ago (except much of it didn't exist yet). I am playing with LS engines these days. But all the principals still apply.

[@edmitchell9307]

I hope you do a whole episode on offset seat profiles

[@chriscimino7854]

Mr. David Vitter I can't tell you how much I enjoy watching your videos. I never ported heads before. I have a pair of Pontiac #13 heads I would like to street pocket port but not ruin them. I am nervous and need to watch as many of your videos as I can to gain confidence. I am trying to build a 400hp 400 cu.in. Pontiac. I am running reproduction ram air three exhaust manifolds and stock four barrel quadrajet intake what do you think?

[@hotrodray6802]

1) Back about 2005 a guy needed new head gaskets so he ported the heads too. He showed me a pair of mid 70s SBC 350 heads he ported (his first try) and I was aghast. Worst mess I ever saw. At least he didn't gouge out the seats. He put them on this ragged out 75 Camaro and it ran like a scalded dog!! Surprised me beyond words. 2) 1970 had a 292 Y block that chunked out an exhaust valve. Got a junk head for $5. Must have been a 239 or 256" with tiny quarter sized valves and tiny chambers. Put it on and it ran perfectly smooth for the next 25 years. Go figure. Never went over 4000 rpm I'm sure. SMH.

[@TIMEtoRIDE900]

Chalk one up for "rough" port finish ?? Some guys are trying to carve golfball pips in. An engine builder told me SBC heads don't need any exhaust port work for the street.

[@jasoncampbell4723]

Cutting pips do help but you need to know where to put them, if you do the whole port it doesn’t work.

[@1crazypj]

That's something new, offsetting the throat diameters!

[@stevesadusky8634]

Thank you David for this video! I'm still trying to understand the porting process as in the past my brother would do all my heads for me because he knew the process inside and out but, he was killed by a drunk driver and I'm on my own now trying to learn the porting process. Do you also have books that I can purchase from you?

[@mcintyretyler89]

I'll be back for the bowl🥣

[@dannykim5969]

i really appreicate your informative videos. thank you sir!

[@christinenevistiuk7906]

Hi David . I get asked a lot about the valve Guide . And is it ok to cut the part level with the port . Is it ? Thank you your knowledge is a gift to us all !!!

[@davidciesielski8251]

Thank you

[@martiniv8924]

Legend 🙌🏻

[@buschenterprises4788]

restriction to cfm on flowbench and restriction to rpm and power capability do not necessarily go hand-in-hand the pushrod pinch may not be a cfm restriction, but it is an rpm and therefore power restriction…depends on cubic inch and desired power level (be reasonable here).

[@jamest.5001]

I was just swiping through, and saw the Chevy head from the chamber, and thought, what if the valve angle were to be reversed? So intake would be similar to the heads being installed backwards, using the intake as exhaust, and exhaust as intake, with the valves reversed, seems high lift flow would be higher, possibly, low lift could be hurt, with the valve opens, the air should have a straight shot into the cylinder. The swirl may be hurt also, but tumble should be greater, but with optimized chambers could inverted valve angles in a wedge chamber, any thoughts?

[@dale116dot7]

The main reason that the valve sizes are what they are is that the intake valve has atmospheric pressure pushing the air into the cylinder and on a naturally aspirated engine any restriction at all in the intake system generates a power loss. The exhaust valve has pressure from the piston pushing the exhaust gas out, and exhaust valve restriction mostly generates internal EGR and reduces scavenging a bit both of which creates a power loss, but not by the same amount. Intake needs to have priority in a naturally aspirated engine. In a turbocharged or supercharged engine it is possible that reversing the valve sizes might be helpful but with the exception of I think some race-prepped nailheads, I don’t think it’s a common way of doing it.

[@robertjohnson4401]

When you said 91%, which measurement is the numerator and which measurement is the denominator. You left that undefined here.

[@michaelau5159]

Percentage is metric it is based on 100. Take whatever your width is and divide it by 100 times by 91 3.g. 2.02/100 x 91 =1.83.

[@ArmySigs]

Great insights!

[@russellanderson746]

Great video Mr. Vizard!! But, I must confess, I don't have a total lock on the percentages and what they mean. Please elucidate sir! Thanks again for the very interesting and valuable information. Also eagerly awaiting more on the Mazda 4 valve porting!

[@DigiMannen]

If it is Concentric. Imagine 90% of valve diameter in the pinch points furthest to intake runner if you have a 2" valve it should be 1.8", 92% is 1.84", 88% is 1.76" so concentric hole where the inner seat width is 1.82" at pinch points and 1.76" seat width perpendicular.

[@russellanderson746]

@@DigiMannen Define pinch point. I'm not hip to all this porting nomenclature. By pinch point do you mean the area in the seat that is directly adjacent to the exhaust valve on one side and cylinder wall on the other? Thanks for the reply, BTW.

[@DigiMannen]

@@russellanderson746 You did not watch the video?

[@DigiMannen]

@@russellanderson746 The red areas! kzbin.info/www/bejne/m32thmSeYteUi8k

[@ElvinLeadfoot]

Going ba k and watching again King David:)

[@rickyhenson4906]

Love all the info

[@gf845]

I can remember 25 years ago now (maybe more) reading your A series tuning book over and over (it was like a bible to me at the time). At the time I had a very slow mini 1000 and a very crashed mg metro 1275 With the A+ engine in. I remember fitting the entire top end from the metro onto the 998 block and it ran and produced so much torque it was always spinning the wheels up in the wet through it’s open diff. I’m sure you said in the book the 12g940 head wouldn’t work on the 1000 block (especially the mg version with the bigger valves). Am I mistaken. The 998 had its standard cam still in it and the engine ran with no problems at all. It was t the most high reving 998 I’ve had but I remember the torque made it great to drive.

[@senghornphon6100]

Thanks for your sharing

[@ziggassedup]

Thanks DV.

[@hotrodray6802]

🔔😎 The name of the game is RESULTS !!!

[@chrispompano]

What firms do Computational Fluid Dynamics for the a mature to send their heads to for analyzing?????????

[@racerd9669]

CID does.

[@chrispompano]

@@racerd9669 Are you referring to Competition Induction Designs?

[@ForceEngineering]

Is your CFD data doing an engine simulation? As in changing the differential pressure across the valve as a result of the % of cylinder filled for a given valve lift. Or is it not taking that into account and is strictly looking at flow with 28" of depression over the lift range?

[@MrKentaroMotoPI]

Doesn't matter unless the CFD result is intended to produce quantitative total airflow results. The solution shows the relative velocities and overall flow distortion (pretty bad, but typical). That's sufficient information to act on.

[@ForceEngineering]

@Mr. Moto The air speed in the port and the direction of flow won't change as the pressure delta is affected by the cyilinder filling?

[@MrKentaroMotoPI]

@@ForceEngineering The pressure difference across the head will affect mass and volumetric flow, and velocity. It won't effect the flow field structure much. Yes, velocity change will change the Reynolds number - which can change the flowfield - but these flows are fully turbulent, so it's a weak effect. It is very important that the CFD model uses a turbulence model, and that it is operating correctly. This flow has a lot of boundary layer separation (blue regions). While the turbulence increases pressure drop, it actually suppresses the separation and helps overall. Poor turbulence simulation is one of the most common problems encountered with CFD.