I'm in Australia and I bought DV's IOP and Torque Master programs. I highly urge you all to do so as well just to support him. DV offers discounts but I made a deliberate decision not to ask for them as I believe that it is the least we can do in appreciation of the work that he is putting in for us viewers. Additionally, I have also replaced some of my earlier DV books with newer ones, simply because it supports DV. By doing this I have purchased some excellent tools and reference materials whilst supporting DV and his team. I urge you all to do similar
Well, that 22 minutes flew past awfully fast. I'm going to save this video and watch it a few more times, there is a lot of great information in there.
Have 8-9 of your books & enjoy all your videos, always come away with atleast one more tidbit of new information or are reminded of something i should not have forgotten from the past. Thanks for the knowledge.
Liked & subscribed. (To original channel years ago and to new channel a couple of months ago). Listening to DV speaking at a sensible speed with so much knowledge to share is highly relaxing and de-stressing from the assaults of daily life.
Loooove the videos!Nobody wants to tell trade secrets, but you guts do a lot to educate! But I do have a suggestion? The intro is really ,really intense,almost scary?! Its almost 2001 intense, not that I'm crying and running for mommy ! It might lighten things up? Thanks again!!
the exhaust port is also fairly important to get more intake flow, if the exhaust goes past the throat and out too fast, reversion will take place because the cylinder pressure will be a lot less than the exhaust manifold pressure, but if the flow is too slow, you'll have exhaust gases left in the cylinder too, so you have to balance the exhaust flow to get the biggest pressure differential across the intake valve. another thing to consider with the exhaust port is that the flow across the throat moves supersonic at high valve lift, so the ideal shape of the throat changes drastically
I can tell that you genuinely enjoy making your videos. That makes absorbing and understanding information much easier as well as memorable. Thank you sir.
I've been reading DVs books for over 40 years and porting my own heads for over 55 years I'm machanics school we had been taught from DVs books my teacher knew his trade and we did a 292 Y block that made 350hp and 430 torque with DVs head porting and manifold mods and cam selection thanks professor it's a pleasure and an honner to be trained by the best ps y blocks don't turn 8000 rpm mine did and it lasted for 20 years till I rebuilt it and it is still alive I sold it to a friend he loves it
More great info. Would be interesting to see some detailed seat cutting with dimensions , seat angles ,widths and prep work. Really enjoy the videos. Keep them coming sir.
Thank you David , You have been a wealth of extremely valuable information that has been presented in a format that is easy to understand for a professional engine builder or a person just starting out on their journey to become a proficient engine builder.
Although I am proponent of a tapered runner to the seat in 4 valve heads I have always been a big proponent of managing bowl volume. A large, properly shaped bowl area is most definitely worth 2% VE as you stated in your video. I agree with everything you stated.
Thank you Professor points we'll take ,I've read some of your books and I've always used the info and my motors have surprised quite a few people, my engine class teacher always used your books for teaching about heads and how to make them better so we used your theary on a set of the worst stock heads ,the Ford Y Block 312 ecz-g heads well after 8 months of porting and massaging the stainless valves we got close to double the flow ,that's what we were trying to do so the class was a great learning tool that's why we call you the professor thanks G B peace
Thank you David and Marvin and Andy. We've been flying blind for decades. The Ford guys have all been running in small tribes all over the nation. In contrast to the Gm guys were much more organized due to there greater parts availability throughout the past 60 years. And Ford never endorsed the Gliddens to help organize us. So we were all cast into local tribal groups scattered across the land. Now David I know your not owned by any group or organization or manufacturer. But you and Andy have given us all a place to call home since we lost Bob Glidden. Thank you. And I am sure there are many people that feel the same.
Enjoy the videos very much. One thing I would like to see is organization of the videos into playlists. As with this video, series aren't often sequential. Thank you for the time, I hope to attend a seminar soon.
Hello David. Your videos give me flash backs. This video for example reminds me a a set of vortec heads I built for a dirt racer. The majority of the work I do to the vortec head is in the bowl, seat , and chamber. When finished assembling the heads I decided I would go help the guy put the engine back together. This guy, if you were to imagine the character Oscar the grouch, saw the heads and discredit my work because the runners were not ported. Laughing, I said let put these on the engine and see how well they run this weekend. After that, I will do whatever else you feel necessary. That modified torqued out of the corner and had a smooth power curve that won that night and at another track Saturday night. After satisfying him the following week with large ported runners, the car did not run as good out of the corner. Ran good at 6,000 rpm and up, but like a lazy dog down low. I told the guy I would build another set for him but at a higher price.
I originally came to this channel because your zero loss exhaust video was suggested to me. I like that you ask for constructive criticism but I'm not sure any is needed. Unfortunately you're speaking to a neich audience but you do it well. I feel like I'm learning a lot from this channel and I'm sure I'll reference these videos during engine projects in the future.
We used a bunch of the Scat rods and found that they all needed to be resized right out of the box. We figured that the rods somewhere had the bolts changed after the machining of the big end. Like you we were looking for perfection.
Another great video, many years ago the theory (by some) for optimum flow, was a taper of 7deg (I found this to be too steep). And then you had the great Auriol Lampredi with the verturi inlet port. Interestingly those little 1300/1500cc sohc fiat heads with a bigger In valve and bowl modified very much like in the vid. flow 122cfm@10" without opening the port. Knocking on the door of 160bhp@8600- 8800 rpm. No one takes any notice as it's only a tiny motor, much easier to go quicker with a bigger one, but the principle to prove the theory is there.
I’m so glad I found this channel. Finding sources on theory and building is so hard on here. One thing I would recommend as a photographer, increasing your production quality would really help convey the info. On the gear side; A full frame DSLR body with a 70-200 and 16-35 lenses would boost video quality tenfold. The 70-200 is good for single subject video. And the 16-35 will let you get more wide shots if you need. If you can only get 1 go with the 70-200. On the editing side, better pacing and b-roll addition for parts you’re discussing can really help keep people engaged.
Another great tutorial. Not a criticism - but it would be nice if your tutorials were grouped into playlists - and don't worry about wardrobe continuity as that's not what we come here to watch for! (Loyal subscriber and long time fan - I even own about a dozen of your books)
Only one complaint David. With all the wealth of information and fluid dynamic theory provided which can easily be applied to many different engines where are the Mopar builds. It’s tough being a Mopar man in a Chevy world.
I have a question for Mr. David, if he ever wrote any performance book about VW 8v. VW 8v are still a big thing in some countries like Brazil, México and south África among many others. Also wold like to see more debate on dimpling, some companies claim that this is a miracle thing. And David, you are doing an amazing work sharing your knowledge to the next generation, in your work and seminars, but also on youtube, I've been a fan of your work since I first hear about you, youtube did not even exist at the moment, never thought that one day I'll be able to see you teaching. Thanks
Another awasom video thanks again I'm just getting ready to do a set of heads and I'm really glad I was able to see this video now I won't be wasting my time and it makes me feel better about doing my head's thanks again
I try to absorb it all. What's to gripe about. Guided restrictions can have efficient results. Like in a tuned pipe. It's usually for staying in a higher rpm. I'm in the wrong class again. Love all the info.
I love all your videos and I wish I had had this resource 40 years ago, however... As a journalist, I offer a constructive criticism. To state in the title "5 rules of head porting" should mean it contains 5 clearly identified rules. Number 1, the bowl, number 2 etc, etc, number 3 etc... To label it as containing 5 things while not clearly identifying those 5 things leaves the viewer slightly dissatisfied like he just spent 30 minutes because he was promised 5 things, but was left with not knowing what or if he actually got them. Otherwise, I've learned so much and please continue! And thank you.
In a diesel head the bowls tend to be very small because they are cast with guides to force swirl. Removing that swirl usually picks up flow big time but that often doesn’t translate to power. Is there a work around?
The continuity bits aren't bothersome in the least to me; but my suggestion is to try and keep attention; the content is amazing but it seems like sometimes my attention drifts during some of the segments of the video. Focus on the really important bits more. You do seem to be getting more comfortable with it as you continue to make videos though; fantastic channel.
Best way to get heads to flow more is just to keep adding boost. Also didn’t like how you left me hanging on aluminium rods made from Russian alloy. Great tutorial don’t mind being schooled by DV
# 1 This is great info for the Diy street guys. But ! New technology in head porting is to make the port smaller and increase the swirl and velocity in the port past Mach speed Without creating "turbulence". (Just like a speed boat goes faster on smooth water vs rough water. In simple terms ) The most over looked is the bowl and seat angles. If there not correct you can loose 10 cfm or more on that port alone. " Right now there are cnc head porters that are producing velocity's beyond what science will tell you is theoretically impossible in these ports. They have spent 100 of hours on one particular head developing these ports. And if you want to be competitive in the racing world Be prepared to spend big $ ( 13,000 for a set of heads and matching intake ) if you want to be competitive. (If you don't have what they have or better you might as well stay home on the porch.) # 2 Scat rods are good rods. Good for the street guy. But the Arp rod bolts are junk. Not Iso certified and the sold there sole to China. All these rods sound good with Arp 2000 bolts But there cheap bolts. There make in China now. One bad rod bolt and your done !! Dont care who's rod it is..... ( This is why more manufactures are making there own rod bolts now. ( Look it up !!! Carrillo , Crower, And others. ) Check any site on these rods and there bolts, Summit, Jegs, Ect, and you will see that they make there own bolts now. ( That tells you something right there ) # 3 Thank you for your videos David. A lot of good information you have acquired threw out your years.
Thanks again for a great video. I am in the process of purchasing a cross ram style intake system. Dyno numbers should be available in about 1 month. Good to know the theory behind the various sections of the intake/port.
Would be great to see you work with the large port 351 Cleveland heads. Is filling the bottom of the port beneficial. Why did Ford use such large ports? I did recall Richard Holdner comparing all the American smallblocks, And the 351 Cleveland definitely made the most horsepower per cube. An analysis of the Cleveland head would allow us to get into the minds of these hard working engineers
JC it's coming. My request to you is to promote out channel on social media and Ford forums. We need at least 25,000 subscribers for me to be able to dedicate the time to this. Thanks
Hello david. My name is Gregorio and I am from Spain, I would like to be able to ask a question and if you would be so kind as to answer me. I have a homemade flowmeter, and I am doing my tests, but I have doubts when I am going to modify the conduit, I do speed tests with the pitot tube as you describe in your book, and I know where I have more speed, now my question where I have from Removing material is where there is more speed or where there is less? I don't know if you have any video explaining this. I want to learn why it is done and how to do it well. Greetings and thanks for your time.
DV-- thoroughly enjoy your videos and very much appreciate them. As I commented on one of your live sessions this date, your acoustics could use some adjustment. Not sure what to recommend, but some fine tuning is needed. Thanks for all you do and for sharing your knowledge. A long-time admirer.
no critique. just a heads up on "my name" some of us "computer nerd's" have a "nick name" and a lot of us actually use it when talking to friends etc. personally i have had this nick from the mid 80's and it's as much me as the one i was given by my parent's ;) and yes the pict is me as well. taken in the first web cam you got in the early 90's ;) love your video's. just trying to soake up some knowledge ;)
Have you done a video on retangle port bbc chevy heads. I HAVE BOTH CLOSED CHAMBER & A SET OF MERLINS THAT ARE OPEN CHAMBER.WILL BE USING WEILAND 1985 TUNNEL RAM WOULD LOVE TO SEE WHAT YOU WOULD DO. THANKS ALOT FOR YOUR INFO. & EXPERIENCE
Hello David, I’ve been watching since the 4th esp. Good stuff ! I have a question about the ports that I’ve noticed with your port molds. I noticed a taper on your vortec port and on your most recent video the port appears straight, or what is called power bucket. Would it benefit my ports to fill it in so that there is less taper to increase velocity ( torque)? Please explain ? Thanks in advance. Neal
I would love for you to elaborate on the ideal radius size of the port entry, in particular in relation to increasing engine speed. Is the smaller radius more ideal at the torque peak? and perhaps a larger radius more effective at the upper end of the RPM range? Or is the small radius optimum at every engine speed? What if the port sizes are already too small, as in the case with Tuned Port Injection where the runners meet the small plenum area?
Now I have to try to put this in action on my inline Chevy 6, with siamesed ports. MONSTER bowl and port size, and no good room to turn the flow into one or the other of the adjacent cylinders. Gotta make the inlet somewhat smaller to get some air speed up, and make the turn too. It looks to me like I need to add material to the sides of the intake port to get size down, but I guess I'll have to let the flow bench tell me how much. I'd bet it's not more than about .060" per side.
I’m not an expert in Chevy 6’s but, I did quite a bit of reasearch on them when my dad was considering building one up for a vintage gasser before the project took a different direction......I’m not sure the power level your attempting to attain but the max effort N/A builds mostly harken back to the Cotton & Perry Nova, and there’s companies that still do a lot of very involved head work on those, like “Sissel Automotive”......from what I can tell the inlet tract volume is needed on the Siamese port because due to firing order there is a LOT of charge stealing going on between paired cylinders, and though extra volume may soften the lower revs, it makes the distribution slightly better and actually allows the needed airflow for higher revs.......if you read a lot of old tech articles on the Chevy 6’s that were campaigned in match racing back then, some even had split duration and split LCA cams ground differently from cylinder to cylinder to keep the charge stealing to a minimum......the only hole hearted recommendation I can give is removing the bolt boss that goes through the Siamese intake port then installing a “lump-port” from “T-6 Racing” will probably get you near 80% of the maximum gains attainable with a factory casting.....after that going to 1.94-intake and 1.6 exhaust valves is most of the rest of the flow, along with de-shrouding the combustion chamber.....Some resources to check out is 12Bolt.com, mrhotrod6.com, and T6Racing.com for parts and information on what I wrote about.
"Bearing-clearence"Difference 10-1000hp.But I removed 50 000km axl scooter.Extreme heavy turning,new.And bearing off 1 day,works like perfectly.Part of a Brake-system.17.1mm axl and 17.2 mm bearing attachment.Sand paper off 0.mm for FREE-PLAY.Front wheel axl 1 mm free-play,crankshaft axl same.Gears all freeplay.
Hey sir a long time reader of all uour material. I have a question for you about the Scat I beam and H beam rods do you think they are equal to the crower rods and cosworth,Oliver and Manley and so on?? I know several engines that are built with them and so far no issues. But I still hear some bashing them. But I do continue to use them and recommend them. Thank you for the videos they are great knowledge. I have many of your books and they are falling apart so tje videos are a big help.
Love your videos and have validated a lot of my own porting and airflow conclusions based on your posts. Alp though I behave a questions that is probably beyond your average head porter or viewer. I have done a good amount of dyno testing and always try to compare ve% to cross-sectional Area vs the average Mach index of the minimum cross-sectional area of the port. My question is we you have optimized both flow and port velocity the theoretical highest port energy has been achieved. So how does this correlate with cylinder filling. And do you believe that sonic choke tanks ve once the port has gone sonic flow is ve is out to lunch.
I would like to hear an answer when the question's are just "classified" and not public. Totally understand, but when learning and asking things this happen, so simple reply would be nice to hear. Thank you Craig for good question. Regarding the optimum flow I'm just thinking are we mainly looking what is the piston asking at a certain rpm? Higher port velocity in the system mean more efficient it is. Adding "choke tanks" what I understand as a increased volume in a intake track make the system les efficient, but may help to fill the cylinder in example higher rpm where the airspeed is otherwise too fast. your respondent - aircraft mechanic and motorsport enthusiast ;) Juhana Huovinen
On the good port of a big block chevy cylinder head do to still want to put a emphasis on increasing the size of the bowl on the cylinder wall side like you mention in this video? Also, Would you put more, less, or the same emphasis on the good port bowl size than you would the bad port? Thanks, Andy.
I'm in Australia and I bought DV's IOP and Torque Master programs. I highly urge you all to do so as well just to support him. DV offers discounts but I made a deliberate decision not to ask for them as I believe that it is the least we can do in appreciation of the work that he is putting in for us viewers. Additionally, I have also replaced some of my earlier DV books with newer ones, simply because it supports DV. By doing this I have purchased some excellent tools and reference materials whilst supporting DV and his team. I urge you all to do similar
You can't beat experience and the naysayers should realize this. Keep up the great work. Your information is of great importance.
Well said sir could not put that any better myself 👍
@@stephanieglass9507 sir🤔🤦♀️
Still the best technical channel on TH-cam. Thank you DV
Well, that 22 minutes flew past awfully fast.
I'm going to save this video and watch it a few more times, there is a lot of great information in there.
Even his videos are tuned to go faster.
Have 8-9 of your books & enjoy all your videos, always come away with atleast one more tidbit of new information or are reminded of something i should not have forgotten from the past. Thanks for the knowledge.
This guy and gale banks are going to engine heaven, it’ll be a sad day when they leave us with all their knowledge.
I believe that David Vizard can actually SEE air. What amazing knowledge and insight.
Liked & subscribed.
(To original channel years ago and to new channel a couple of months ago).
Listening to DV speaking at a sensible speed with so much knowledge to share is highly relaxing and de-stressing from the assaults of daily life.
This channel is a treasure trove of priceless advice. Really top notch
David, you are the best I,ve ever learned from in my life! AND,GOD BLESS JACQUE!!!!!!!!!!!!! 😊
Loooove the videos!Nobody wants to tell trade secrets, but you guts do a lot to educate! But I do have a suggestion? The intro is really ,really intense,almost scary?! Its almost 2001 intense, not that I'm crying and running for mommy ! It might lighten things up? Thanks again!!
Fast forward through the intro.
the exhaust port is also fairly important to get more intake flow, if the exhaust goes past the throat and out too fast, reversion will take place because the cylinder pressure will be a lot less than the exhaust manifold pressure, but if the flow is too slow, you'll have exhaust gases left in the cylinder too, so you have to balance the exhaust flow to get the biggest pressure differential across the intake valve.
another thing to consider with the exhaust port is that the flow across the throat moves supersonic at high valve lift, so the ideal shape of the throat changes drastically
I love these videos! From the intense intro, the great content, and the somber background music. Don’t change a thing! David is the man!
I can tell that you genuinely enjoy making your videos. That makes absorbing and understanding information much easier as well as memorable. Thank you sir.
I've been reading DVs books for over 40 years and porting my own heads for over 55 years I'm machanics school we had been taught from DVs books my teacher knew his trade and we did a 292 Y block that made 350hp and 430 torque with DVs head porting and manifold mods and cam selection thanks professor it's a pleasure and an honner to be trained by the best ps y blocks don't turn 8000 rpm mine did and it lasted for 20 years till I rebuilt it and it is still alive I sold it to a friend he loves it
More great info. Would be interesting to see some detailed seat cutting with dimensions , seat angles ,widths and prep work.
Really enjoy the videos. Keep them coming sir.
Thank you David , You have been a wealth of extremely valuable information that has been presented in a format that is easy to understand for a professional engine builder or a person just starting out on their journey to become a proficient engine builder.
David, you can't reason with those types, don't change a single thing.
Best wishes,
Roger....... Uk
I LOVED that line about excess intake port volume-flow was only useful for teenage drivers!
Yes, that's a good one!
David, thanks so much for taking the time to help us all understand. Your experience and wisdom has helped me a lot with my 331 build!
Great video as always David, thank you for sharing your knowledge
DV- we don't worry about your shirts. Carry-on.
@@chevyfarmersgarage1955 😂😅👍
Although I am proponent of a tapered runner to the seat in 4 valve heads I have always been a big proponent of managing bowl volume. A large, properly shaped bowl area is most definitely worth 2% VE as you stated in your video. I agree with everything you stated.
Thank you Professor points we'll take ,I've read some of your books and I've always used the info and my motors have surprised quite a few people, my engine class teacher always used your books for teaching about heads and how to make them better so we used your theary on a set of the worst stock heads ,the Ford Y Block 312 ecz-g heads well after 8 months of porting and massaging the stainless valves we got close to double the flow ,that's what we were trying to do so the class was a great learning tool that's why we call you the professor thanks G B peace
Richard, thank you for your thoughtful comments. DV
great videos, thank you for the contribution to the combustion engine tuning world.
Thank you so much for everything you have done for teaching engine building David.
Thank you David and Marvin and Andy. We've been flying blind for decades. The Ford guys have all been running in small tribes all over the nation. In contrast to the Gm guys were much more organized due to there greater parts availability throughout the past 60 years. And Ford never endorsed the Gliddens to help organize us. So we were all cast into local tribal groups scattered across the land. Now David I know your not owned by any group or organization or manufacturer. But you and Andy have given us all a place to call home since we lost Bob Glidden. Thank you. And I am sure there are many people that feel the same.
This is by far the best information I've ever come across. I'm a good builder, but this is absolutely brilliant.
Enjoy the videos very much. One thing I would like to see is organization of the videos into playlists. As with this video, series aren't often sequential. Thank you for the time, I hope to attend a seminar soon.
Watching these videos are as relaxing as watching Bob Ross paint. Thank you sir
I have absolutely no complaints! This is such a great series! Keep it up 👍
Hello David. Your videos give me flash backs. This video for example reminds me a a set of vortec heads I built for a dirt racer. The majority of the work I do to the vortec head is in the bowl, seat , and chamber.
When finished assembling the heads I decided I would go help the guy put the engine back together. This guy, if you were to imagine the character Oscar the grouch, saw the heads and discredit my work because the runners were not ported.
Laughing, I said let put these on the engine and see how well they run this weekend. After that, I will do whatever else you feel necessary. That modified torqued out of the corner and had a smooth power curve that won that night and at another track Saturday night.
After satisfying him the following week with large ported runners, the car did not run as good out of the corner. Ran good at 6,000 rpm and up, but like a lazy dog down low.
I told the guy I would build another set for him but at a higher price.
That Australian V8 super car intake casting is a thing of beauty. Cross Ram of destiny!
David!! Don’t worry about the clown. You are the man and arm chair pros are always going to do that. Your doing fine and I love your work.
I originally came to this channel because your zero loss exhaust video was suggested to me. I like that you ask for constructive criticism but I'm not sure any is needed. Unfortunately you're speaking to a neich audience but you do it well. I feel like I'm learning a lot from this channel and I'm sure I'll reference these videos during engine projects in the future.
We used a bunch of the Scat rods and found that they all needed to be resized right out of the box. We figured that the rods somewhere had the bolts changed after the machining of the big end. Like you we were looking for perfection.
read alot of your books Mr. Vizard. Learned alot
Thank you for the educational value of this presentation!
The ONLY issue I've been able to come up with is the misspelling of "psychology" in the intro text. Great job!
You are a wealth of knowledge, thank you Sir.
Another great video, many years ago the theory (by some) for optimum flow, was a taper of 7deg (I found this to be too steep). And then you had the great Auriol Lampredi with the verturi inlet port. Interestingly those little 1300/1500cc sohc fiat heads with a bigger In valve and bowl modified very much like in the vid. flow 122cfm@10" without opening the port. Knocking on the door of 160bhp@8600- 8800 rpm. No one takes any notice as it's only a tiny motor, much easier to go quicker with a bigger one, but the principle to prove the theory is there.
Doing good Dav, old school common ( cents). keep going.
I’m so glad I found this channel. Finding sources on theory and building is so hard on here. One thing I would recommend as a photographer, increasing your production quality would really help convey the info.
On the gear side; A full frame DSLR body with a 70-200 and 16-35 lenses would boost video quality tenfold.
The 70-200 is good for single subject video. And the 16-35 will let you get more wide shots if you need. If you can only get 1 go with the 70-200.
On the editing side, better pacing and b-roll addition for parts you’re discussing can really help keep people engaged.
Hey, you should have Larry Scheib or Bob Mullen in to took about race hemis, engine books and the max wedge airflow principle someday
Another great tutorial. Not a criticism - but it would be nice if your tutorials were grouped into playlists - and don't worry about wardrobe continuity as that's not what we come here to watch for! (Loyal subscriber and long time fan - I even own about a dozen of your books)
Another great video David like always can't wait to get to one of your seminars or you're porting class would be even better
Only one complaint David. With all the wealth of information and fluid dynamic theory provided which can easily be applied to many different engines where are the Mopar builds. It’s tough being a Mopar man in a Chevy world.
3:41 David
Jay Leno
Has worn the same blue shirt for 30+ years.
I thoroughly enjoy your Powertec videos. Very well done.
You have my attention 100% Dave.
Ziggy in Australia.
David your seminars are great! You should have 10x the subscribers!
I have a question for Mr. David, if he ever wrote any performance book about VW 8v.
VW 8v are still a big thing in some countries like Brazil, México and south África among many others.
Also wold like to see more debate on dimpling, some companies claim that this is a miracle thing.
And David, you are doing an amazing work sharing your knowledge to the next generation, in your work and seminars, but also on youtube, I've been a fan of your work since I first hear about you, youtube did not even exist at the moment, never thought that one day I'll be able to see you teaching.
Thanks
I believe he did.
GREAT ONE DAVID
Another awasom video thanks again I'm just getting ready to do a set of heads and I'm really glad I was able to see this video now I won't be wasting my time and it makes me feel better about doing my head's thanks again
David and Marvin, very good content, with quality technical matters with many details and secrets, thanks for conpartillar
David thank you so much for sharing this information. I cant wait to put all of it into practice someday!
Thank you for everything
Thank you David.
I try to absorb it all. What's to gripe about. Guided restrictions can have efficient results. Like in a tuned pipe. It's usually for staying in a higher rpm. I'm in the wrong class again.
Love all the info.
I love all your videos and I wish I had had this resource 40 years ago, however... As a journalist, I offer a constructive criticism. To state in the title "5 rules of head porting" should mean it contains 5 clearly identified rules. Number 1, the bowl, number 2 etc, etc, number 3 etc... To label it as containing 5 things while not clearly identifying those 5 things leaves the viewer slightly dissatisfied like he just spent 30 minutes because he was promised 5 things, but was left with not knowing what or if he actually got them. Otherwise, I've learned so much and please continue! And thank you.
Sir you are a gentleman. privileged to watch
Re: Scandium. S&W used it for pistol frames a while back ,and True Temper made golf shafts with it too in the 90's . Brutally expensive!
Great knowledge in every video can't put a price on what I get from each video great job 👌👍😎
In a diesel head the bowls tend to be very small because they are cast with guides to force swirl. Removing that swirl usually picks up flow big time but that often doesn’t translate to power. Is there a work around?
Yes - I will detail diesel mods and hopefully dyno and f/bench results about 7-8 episodes down the road.
DV
Great video.
HEY MJ i've never even noticed weather hes even got a shirt on or not, im here for the TECH!
The continuity bits aren't bothersome in the least to me; but my suggestion is to try and keep attention; the content is amazing but it seems like sometimes my attention drifts during some of the segments of the video. Focus on the really important bits more. You do seem to be getting more comfortable with it as you continue to make videos though; fantastic channel.
Troy read the post a couple up from here. I am doing my best here but it's not as good as I would like. Old age and all that.
DV
@@marvingvx1 It shows that you are putting in a real effort; you have some great information in all of your videos! keep at it!
Best way to get heads to flow more is just to keep adding boost. Also didn’t like how you left me hanging on aluminium rods made from Russian alloy. Great tutorial don’t mind being schooled by DV
thank you sir much love
# 1 This is great info for the Diy street guys. But ! New technology in head porting is to make the port smaller and increase the swirl and velocity in the port past Mach speed Without creating "turbulence". (Just like a speed boat goes faster on smooth water vs rough water. In simple terms ) The most over looked is the bowl and seat angles. If there not correct you can loose 10 cfm or more on that port alone. " Right now there are cnc head porters that are producing velocity's beyond what science will tell you is theoretically impossible in these ports. They have spent 100 of hours on one particular head developing these ports. And if you want to be competitive in the racing world Be prepared to spend big $ ( 13,000 for a set of heads and matching intake ) if you want to be competitive. (If you don't have what they have or better you might as well stay home on the porch.) # 2 Scat rods are good rods. Good for the street guy. But the Arp rod bolts are junk. Not Iso certified and the sold there sole to China. All these rods sound good with Arp 2000 bolts But there cheap bolts. There make in China now. One bad rod bolt and your done !! Dont care who's rod it is..... ( This is why more manufactures are making there own rod bolts now. ( Look it up !!! Carrillo , Crower, And others. ) Check any site on these rods and there bolts, Summit, Jegs, Ect, and you will see that they make there own bolts now. ( That tells you something right there ) # 3 Thank you for your videos David. A lot of good information you have acquired threw out your years.
Thanks again for a great video. I am in the process of purchasing a cross ram style intake system. Dyno numbers should be available in about 1 month. Good to know the theory behind the various sections of the intake/port.
Дай бог вам здоровья чтобы дольше делились своими знаниями
My left earpiece went out. The music had me double-checking my video. Hahahahaha
Thanks David. Great information. Have a great day,
Would be great to see you work with the large port 351 Cleveland heads. Is filling the bottom of the port beneficial. Why did Ford use such large ports? I did recall Richard Holdner comparing all the American smallblocks, And the 351 Cleveland definitely made the most horsepower per cube. An analysis of the Cleveland head would allow us to get into the minds of these hard working engineers
JC it's coming. My request to you is to promote out channel on social media and Ford forums. We need at least 25,000 subscribers for me to be able to dedicate the time to this.
Thanks
Hello david.
My name is Gregorio and I am from Spain, I would like to be able to ask a question and if you would be so kind as to answer me.
I have a homemade flowmeter, and I am doing my tests, but I have doubts when I am going to modify the conduit, I do speed tests with the pitot tube as you describe in your book, and I know where I have more speed, now my question where I have from Removing material is where there is more speed or where there is less?
I don't know if you have any video explaining this.
I want to learn why it is done and how to do it well.
Greetings and thanks for your time.
DV-- thoroughly enjoy your videos and very much appreciate them. As I commented on one of your live sessions this date, your acoustics could use some adjustment. Not sure what to recommend, but some fine tuning is needed.
Thanks for all you do and for sharing your knowledge. A long-time admirer.
Mr. McNelly sir,
Thanks for you audio advice. We are working on an echo reduction wall that won't be noticed. Let us know how we do.
DV
@@marvingvx1 DV- will do. Also, if you could do a little more on the recent recommended valve angles for the 5.3 vortec, it would be appreciated.
Good talk, I learned from your straight port diagram. Thank you.
Is the Kevin you referred to Kevin Cameron (Cammer-Ron) currently with the tech column at Cycle World?
YES YEs Yes yes. Memory failure there. Kevin - good guy, well educated in automotive stuff. Many thanks for the correction.
DV
nice keep it up
Thank you
I wish you would do more Mopar head videos I have not seen one yet.
The bowl is where all the magic happens.
I once again learned something. Thanks
Finally !!!
After 3 month waiting
Thanks!
Another very interesting video ! Thanks.
Thanks David! I always learn something!
no critique. just a heads up on "my name" some of us "computer nerd's" have a "nick name" and a lot of us actually use it when talking to friends etc. personally i have had this nick from the mid 80's and it's as much me as the one i was given by my parent's ;) and yes the pict is me as well. taken in the first web cam you got in the early 90's ;) love your video's. just trying to soake up some knowledge ;)
Have you done a video on retangle port bbc chevy heads. I HAVE BOTH CLOSED CHAMBER & A SET OF MERLINS THAT ARE OPEN CHAMBER.WILL BE USING WEILAND 1985 TUNNEL RAM WOULD LOVE TO SEE WHAT YOU WOULD DO. THANKS ALOT FOR YOUR INFO. & EXPERIENCE
Hello David,
I’ve been watching since the 4th esp.
Good stuff !
I have a question about the ports that I’ve noticed with your port molds.
I noticed a taper on your vortec port and on your most recent video the port appears straight, or what is called power bucket.
Would it benefit my ports to fill it in so that there is less taper to increase velocity ( torque)?
Please explain ?
Thanks in advance.
Neal
Hmm. My wife is headed back to her home town (Kiev) for a short visit this week. Maybe she should bring back some Scandium.
I race Oldsmobile and would love to see head porting for an Oldsmobile cylinder head!
I would love for you to elaborate on the ideal radius size of the port entry, in particular in relation to increasing engine speed. Is the smaller radius more ideal at the torque peak? and perhaps a larger radius more effective at the upper end of the RPM range? Or is the small radius optimum at every engine speed? What if the port sizes are already too small, as in the case with Tuned Port Injection where the runners meet the small plenum area?
thanks David,great content.
Now I have to try to put this in action on my inline Chevy 6, with siamesed ports. MONSTER bowl and port size, and no good room to turn the flow into one or the other of the adjacent cylinders. Gotta make the inlet somewhat smaller to get some air speed up, and make the turn too. It looks to me like I need to add material to the sides of the intake port to get size down, but I guess I'll have to let the flow bench tell me how much. I'd bet it's not more than about .060" per side.
I’m not an expert in Chevy 6’s but, I did quite a bit of reasearch on them when my dad was considering building one up for a vintage gasser before the project took a different direction......I’m not sure the power level your attempting to attain but the max effort N/A builds mostly harken back to the Cotton & Perry Nova, and there’s companies that still do a lot of very involved head work on those, like “Sissel Automotive”......from what I can tell the inlet tract volume is needed on the Siamese port because due to firing order there is a LOT of charge stealing going on between paired cylinders, and though extra volume may soften the lower revs, it makes the distribution slightly better and actually allows the needed airflow for higher revs.......if you read a lot of old tech articles on the Chevy 6’s that were campaigned in match racing back then, some even had split duration and split LCA cams ground differently from cylinder to cylinder to keep the charge stealing to a minimum......the only hole hearted recommendation I can give is removing the bolt boss that goes through the Siamese intake port then installing a “lump-port” from “T-6 Racing” will probably get you near 80% of the maximum gains attainable with a factory casting.....after that going to 1.94-intake and 1.6 exhaust valves is most of the rest of the flow, along with de-shrouding the combustion chamber.....Some resources to check out is 12Bolt.com, mrhotrod6.com, and T6Racing.com for parts and information on what I wrote about.
"Bearing-clearence"Difference 10-1000hp.But I removed 50 000km axl scooter.Extreme heavy turning,new.And bearing off 1 day,works like perfectly.Part of a Brake-system.17.1mm axl and 17.2 mm bearing attachment.Sand paper off 0.mm for FREE-PLAY.Front wheel axl 1 mm free-play,crankshaft axl same.Gears all freeplay.
Hey sir a long time reader of all uour material. I have a question for you about the Scat I beam and H beam rods do you think they are equal to the crower rods and cosworth,Oliver and Manley and so on?? I know several engines that are built with them and so far no issues. But I still hear some bashing them. But I do continue to use them and recommend them. Thank you for the videos they are great knowledge. I have many of your books and they are falling apart so tje videos are a big help.
Love your videos and have validated a lot of my own porting and airflow conclusions based on your posts. Alp though I behave a questions that is probably beyond your average head porter or viewer. I have done a good amount of dyno testing and always try to compare ve% to cross-sectional Area vs the average Mach index of the minimum cross-sectional area of the port. My question is we you have optimized both flow and port velocity the theoretical highest port energy has been achieved. So how does this correlate with cylinder filling. And do you believe that sonic choke tanks ve once the port has gone sonic flow is ve is out to lunch.
I would like to hear an answer when the question's are just "classified" and not public. Totally understand, but when learning and asking things this happen, so simple reply would be nice to hear.
Thank you Craig for good question.
Regarding the optimum flow I'm just thinking are we mainly looking what is the piston asking at a certain rpm? Higher port velocity in the system mean more efficient it is. Adding "choke tanks" what I understand as a increased volume in a intake track make the system les efficient, but may help to fill the cylinder in example higher rpm where the airspeed is otherwise too fast.
your respondent - aircraft mechanic and motorsport enthusiast ;)
Juhana Huovinen
On the good port of a big block chevy cylinder head do to still want to put a emphasis on increasing the size of the bowl on the cylinder wall side like you mention in this video?
Also, Would you put more, less, or the same emphasis on the good port bowl size than you would the bad port?
Thanks, Andy.