Ignition timing tech you probably did not know!

In this, episode 120 of PowerTec 10, DV details what an engine needs for the most efficient use of the fuel involved.
Knowing the "why's" of ignition timing can result in a far smoother and lower idle RPM as well as a more authoritative "lope" when a big cam is used. He talks about one big cammed 500 inch test BB Chevy motor that, on the dyno, idled at an amazingly low 200 RPM!
All the advice applies to both carburated and EFI motors be they street or race. A smooth and consistent idle, whether it has a big cam lope or not is the mark of professionalism. This video shows just how to do it.

[@philzellmer6073]

Great video David! I've been trying to convince others about manifold vacuum for street use for nearly fifty years now. Some get it, others don't. It's ok though, my car pulls their's in straight line accell anyway!....Thanks again for the great work!

[@CatDaddyTuning]

You’d be shocked how many computers get tuned following the same bad advance curves and locked out.

[@apachebill]

Problem with manifold vacuum is as soon as you blip the throttle all the vacuum advance goes away and then comes back, then when you go to full throttle it goes away a second time. Check it with a vacuum guage. Your vacuum can is pulled in at idle on manifold vacuum. As soon as you touch the throttle the vacuum momentarily drops and the distributor retards all the way back to base timing then, immediately sucks the can back in and advances the ignition again. 2 tenths of a second later. So, because that’s actually worth near .2 seconds, I took my HEI apart put a 5.5 mm cap screw in the inside hole under the rotor. Now I idle at 30°, with only 6° mechanical advance and another 14 in the can on ported vacuum. 2 tenths sir. That’s what you lose watching that can reel in and out, in and out. Don’t even have to have a guage to check me. Put your finger on the vacuum advance rod and blip the throttle and you can literally feel all that advance duck out the exact moment you need it only to return after you’ve lost. Better to set the distributor up for the initial you need rather than lean on the can. I did it. I get It.works. But for that one fatal flaw. Makes them start and idle better and smoother and cleaner and much cooler. I really needed the idle cooling. But I felt the launch wasn’t right and that is when I discovered all I wrote above. And I’ve seen it on every car I check. Hook up a vacuum guage. Just flick the throttle and watch the vacuum drop and come back. That’s what the vacuum can was doing too on manifold vacuum. So I was set up at 12° with 24° and 14° on the can. I’d idle at 26° with the can on manifold vacuum and as soon as you touch the throttle… boom! 12° launch. Then back to 36° by 1500. With the 5.5mm cap screw I launch part throttle, 2k rpm at 50°, soon as I stab the throttle it sucks back to 36° and there’s your .2 They said it wouldn’t work on a 10.75/1 iron head pump gas Pontiac. That “it would tear the nose cone off the starter and detonate, destroying the engine.” They lied. Try it. You’ll see.

[@philzellmer6073]

If you're drag racing you don't need vacuum advance.....DV's point is that vac. adv. is for street cars where economy is important.....@@apachebill

[@thisisyourcaptainspeaking2259]

Consult the canister specs. You must have the correct vacuum can calibrated for intake vacuum. Most every later canister was calibrated for carb vacuum, that's why they don't work well with manifold vacuum. The carb vacuum canisters will drop out way before a canister calibrated for manifold vacuum, Vacuum advance retards out of time with throttle butterflys if connected to manifold vacuum.

[@thisisyourcaptainspeaking2259]

​@@apachebillThe reason timing drops out is because it's the incorrect canister. A manifold canister remains all-in during light throttle tip-in.

[@Crazy8ts]

this guy is a mastermind of mechanical knowledge

[@tylervassar714]

Thank you so much! I've screwed around with timing and mixtures for years but never pit it into the proper sequence. It's like a slap in face looking at it now.

[@AlexJonesWasRight1776]

Proud to say I have a Progression Ignition HEI on my 400 SBC!

[@danielmauter1737]

Dr.David!!. Excellent as always!!. I've been following you for 35+ years following a purchase of one of your books at a Swap meet. Then every time a new one came out. I jump on it. I'm sure I have a dozen already. Take care and God Bless..😊

[@DavidVizard]

Daniel, Just wanted to thank you for your considerate thoughts. Take care.

[@buildaboiworkshop]

Dr 😂😂😂😂😂😂

[@sidecarbod1441]

My understanding is that as long as an engine conforms to the accepted standards such as conrod ratio, bore to stroke ratio and things like that then any engine will want peak cylinder pressure to occur between 14-20 degrees ATDC, this is a purely mechanical thing, it is to do with the angle that the conrod forms with the crank, the likes of Ricardo worked this out years ago. The graph at 15:34 shows peak pressure a little later at around 20-22 degrees but at least its in the 'ball park' with what I have read. All of the tricks that we have to do with mechanical advance and vac advance is all to achieve peak cylinder pressure at the right point in crank degrees on the power stroke. Obviously an engine operates in many different 'modes' and at a range of RPM's such as peak RPM at WOT and mid range RPM with the throttle just cracked open (and different AFR for different modes), all of this stuff effects the burn speed which is why we need to adjust when we light up the mixture in the first place. I read some interesting things about how to select a vac canister, basically if an engine pulls lets say 18" on idle then you must select a canister that is 'all in' with 1.5-2" less vacuum, otherwise the timing will bounce in and out. I found it quite hard to find suitable canisters for some engines, the programable MSD 6AL running a locked out dizzy and a MAP system solves the problem nicely! I recently had a big argument with a "professional" 2 stroke tuner here on youtube, he stated that he was working towards getting peak cylinder pressure at TDC! I quickly concluded that he is an idiot!

[@gergatron7000]

I have one thing to note about using vacuum advance straight from manifold. When using a stock-style distributor, I did achieve a very smooth and quiet idle (heard through the exhaust), along with great steady-state cruise and light throttle performance with direct manifold advance. However, when the throttle was opened under even moderate acceleration, there was a moment of severe detonation as the vacuum canister responded to load. No matter what timing setting I tried, there was no compromise or getting around the slow response time of the vacuum advance. In the end, I installed an MSD 6AL programmable which has a MAP sensor input (equivalent to a vac advance) but you can fully customise the entire vacuum curve, as well as the rpm curve, and the timing response is instant. I am currently running around 28 degrees at idle on a closed chamber, 10:1, mild-cammed 302 Cleveland. Approx 45 degrees total under vacuum, back to 35 under load. It starts first kick with no choke and one pump of the throttle (even in winter). Idles beautifully at 850, only time I ever see a hint of detonation is when in traffic on a hot day and the temp is above 3/4 (which is rare). I run E10 exclusively, which my engine loves the most. I most certainly agree that the vac advance at idle should be maximised, but in my experience, using the canister (which requires physical actuation) does not pull timing back quickly enough to allow safe acceleration. Using a programmable electronic ignition provides an instant response.

[@DavidVizard]

could not agree more. Nothing beats a electronic fully programable ignition system. Thanks for your excellent appraisal.

[@sidecarbod1441]

The MSD 6AL Programmable is the only system that I will consider using for any engine that I build, In the UK the Rover V8 engine is still a popular choice for hot-rodding, I take the standard Rover dizzy, I remove all the internals and the fit my own stuff inside the standard dizzy, it is a locked out system using the MSD pickup coil, the improvement over the stock setup is "shocking" !!! I run a MAP system. The programable system is not used much in the UK, I think it is because people shy away from learning how to program it. I wish they would update the 9 pin cable to a USB setup!

[@gordowg1wg145]

The problem can be reduced by ensuring a large internal diameter through-out, as some fittings and/or hoses are relatively small and don't dump the air in the canister fast enough. A second problem may be the characteristics of the vacuum canister used on the distributor, as they're available in a range of values, and your's may have applied more advance at part vacuum/throttle than the engine required, and switching out to a lower/higher value would bring in less advance for that engine vacuum. Perhaps looking for an adjustable aftermarket unit would be a good move?

[@peteloomis8456]

​@@gordowg1wg145 The Chrysler electronic vacuum advance electronic distributor for small blocks and big block have an adjustable vacuum advance canister that can bet changed using a small Allen wrench through the hole that the vacuum advance canister has in it where the vacuum hose connects. Mopar Performance used to sell advance curve springs and weights to change your advance curves and how fast or slow you need them to be.

[@trivigonzales]

Does this practice Work for any carbureted vehicle or only for high-powered performance carbureted vehicle ? I have a 1949 Chevy deluxe with the two 216 in line six all original and I would love to be able to get the maximum performance out of that motor while cruising on the freeway I 55 mph is there any help you can give me or guide me into the right direction on how to get maximum performance out of my car

[@petercermak4095]

Hello Mr. Vizard. New subscriber here. Been watching your videos and taking notes. Wish I found you back in 76 when I started building my street cars. Saw a recent video from Richard touting the benefits of LSA selection. Looks like he switched camps!

[@dadalebreton184]

For the common backyard mecanic who always been learning from usual mecanic so called "experts", its hard to know the difference sometime from what is good and what is best when we were tought "This or That" way. Realizing some teachings were not always the BEST, is sometime difficult to master without starting all over again. Thanks for sharing these gold knowledges. I respect you and Andy very much for what you and everyone who does there best to help us, New and old backyard DIY mecanics and race lovers. Happy New Year everyone !

[@DavidVizard]

Thanks for your kind comments - especially about Andy as he is about as close to ireplaceable as it gets.

[@Barry-tp2vd]

I totally agree. Overconfident fools never realize or consider (as its impossible for them) 'how much they don't know'. However the humble genius will realise how much they don't know yet (and often understate their own abilities as a result). David here is on another level . Huge respect and thanks for all he gives .

[@alanwilliams8078]

Regarding the comments on your Holley book, I would just like to say that I own many of your books, starting with your Mini books when I was a young man starting out modifying and racing cars, I would consider any book or article written by you as the best on that subject, and your videos here are the same - and thank you for being so generous with your knowledge.

[@wantkixido]

Yes, I agree. Well said @allanwilliams8078. Thank you, Mr. Vizard!

[@mechanknuckle]

I'm a classic car mechanic (currently at a British Specialty shop) and even though I now deal with Jaguar, MG, Austin Healey and Triumphs with SU, Stromberg and Weber carbs, I keep the How to Tune a Holley Carb book in my box. Ignition and Air/Fuel principles apply across all cars with carburetors. From time to time we get Holley's coming in on something, and even though I can rebuild a Holley with my eyes closed-- TUNING one to perfection is always worth opening the book.

[@rotaxtwin]

That's good info. I had a reasonable understanding of combustion chamber events but DVs deep explanation & gripping sound effects help to bring it home. I think i will be watching parts of this again & again.

[@DavidVizard]

"Gripping sound effects". I had a good chuckle over that one!!!!

[@wantkixido]

yeah! Me too!!! @@DavidVizard

[@monadking2761]

You always have great information. I am still a carburetor guy. I remember when Excell was in Branford Ct. and went to their car shows and have one of their duel ponts distributors. Now they are in Meriden, which I have driven by many times and remember the good old days. I can't wait for warmer weather now to get back to my 55 Chevy with a 355.

[@groundpounder55]

I'm sitting here wide eyed wishing I could just open up my head cheese and scoop this knowledge in. When I was a teenager 25 years ago, I felt the same way when cousin John came to town and tried explaining the principles to me out of his notebooks filled with equations, telling me the stories from racing on John Bradley's team before Manthis engineering came about. All them family members aren't here anymore for me to ask now that I am trying harder to comprehend the knowledge. Gentlemen like you willing to share the intricate details of their knowledge are priceless. Let's face it, quickly becoming a lost piece of the passion for the hobby when the technology exists for my kids to just bolt stuff on and let computers take over. I would stand in line for a tech seminar or event, just to try and absorb what I need to really enjoy my old Fords. I'll get there, just need to set your channel on repeat

[@Adrenacyde]

DV: In the next installment of this Topic, can you please include the nuances between in and out of gear idle when using an automatic transmission? There usually isn't a lot of clarity here. Take care!

[@ringgap]

For me, in Park is 14:1 and in Drive with my foot on the brake and stopped, I'm between 14.4 and 15:1. If I tune to highest vacuum at idle while in Drive, then I'll be too rich in Park. 750rpm in Park and 650rpm in Drive. 20inHg in Park and 18inHg in Drive. I never run my AFR gauge at less than 13.5:1 at idle because the instructions said it will break the O2 sensor.

[@JudgeMeNotLeMans]

@Adrenacyde follow DV’s procedure to set idle. Once set you may need to increase idle with the idle screw (not idle mixture) just enough to prevent the engine from stalling when the transmission is put into reverse or drive. Most manufacturers have a set idle while in gear which is a good starting point but these are factory settings and may not apply if your combination is not stock.

[@brocluno01]

Good episode. Some aviation folks have been flying "Lean of Peak" for decades. That is they keep leaning their mixtures to peak EGT and then they keep going until the engine gets to weak to maintain RPM. Then slightly fatten up and fly on. This is to save fuel on long cruises. Airplanes don't have vacuum advances. But they do have wide ranging mixture controls 😊

[@andrewforrest1088]

When it comes to reviews on anything, I’ve always said most people that leave bad reviews on products are also the ones who are expecting that product to do or contain something that wasn’t even advertised. I’ve been reading David’s books and watching these videos for awhile and he is one of very few people that actually wants to pass on all of the knowledge he has for those willing to pay attention and listen. I would be more than happy to know just the things that he’s forgotten. Keep up the amazing work Mr. David

[@markerwin7416]

David, I cannot thank you enough for making this video. This information is priceless, and nearly impossible to find online, as there are too many people out there with opinions rather than facts. I've been searching for this *exact* information for months, and you sir are the ONLY source I could find with reliable, specific, universally applicable step-by-step guidance on how to set up a Holley idle circuit perfectly. While this information might be in a book somewhere, us young guys dont have mentors with enough experience to tell us what books we can turn to for this info, and most book stores don't carry the good stuff like they used to. Again, I thank you. I thank you A LOT. You are a true hero to the hot rodders.

[@bobyk87]

He's still quite consistent. I'm particularly intrigued by how the ported vacuum advance works together with the carb's accelerator pump on old classic cars to give an imediate burst of "response" at quick yet slight throttle movement: (1) There's static timing at idling (10 to 15°); (2) vacuum advance kicks in with a peak at maximum vacuum (up to 15° as the accelerator pump jets squirt down); (3) mechanical timing starts kicking according to rpm (two weights and 2 different springs!); (4) vacuum decreases and mechanical keeps rising as rpm goes up, (5) close to WOT vacuum goes to zero so only mechanical + static remain. So static + vacuum = 30° is possible (and needed) way sooner than expected! Another thing: idle mix is richer and cooler, WOT is leaner, more efficient but also hotter. Alcohol blends of nowadays may require some carb tuning for a richer idling mixture, + timing compensation.

[@PetesSnakeBiteKit]

This is one of the best videos so far. You stretch my brain like Smokey did. Thanks!

[@shane-222]

Excellent sound effects. Excellent content. Thanks!🎉

[@Z06RFan]

Always really Great Information Mr. Vizard. Thank you for your time and knowledge and putting it into video form. It is greatly appreciated.

[@patrickmazzone9066]

Glad to see you back

[@josephnickola877]

excellent video David I'm gonna probably have to watch this a few times to absorb all this information much respect

[@frankjones4094]

Another session of learning from the professor. Thank you.

[@timothyjudsontaylorofficia9786]

The master speaks, us mere mortals are blessed by his wisdom. Mad respect for Mr. Vizard!

[@cannaroe1213]

So glad David is still making videos, because I always learn something and the comments/channel really doesn't suffer BS lightly.

[@BretShell-hp9ng]

Most excellent engine information. I have knowledge of set up for smog or emissions testing many years now. Carburetors gone somewhat feedback at this point. The year was 1983 when I started listen to the old man read the underlying info he's genius. Thank you David you rock

[@thomasabbe8964]

Thank you for this master class on Weber emulsion tubes! (from another Weber and Mini Cooper expert) I have been following your lead for 50 years

[@ericcraig8205]

Hi David,good to know your still at it,ive still got your book i used on tuning my twin cam back in the early seventys,seems like you migrated stateside,take care and thanks for so much knowledge and fun over the years from blighty.

[@adeptpeasant6161]

You're a stellar chap. Thanks for your works

[@Sandmann1968]

Your Holley Carb book is amazing. Thank you for that.👍

[@biastv1234]

Another excellent episode. Thank you

[@3Repete]

David, you just made me think back to my college math classes with describing burn rates. If I understand you, it is this way because each burning molecule ignites others around it. And they in turn ignite that many others around them. And the process grows and repeats until the fuel, and commensurately stroke, are completed. I'd say you were calling the burn rate an exponential acceleration that was occurring until the available fuel was used up. The whole arrangement is varied by engine speed, fuel mixture and load using vacuum advance as a guide to control spark advance. These are things I felt that I understood, but you have really clarified their interrelationships. Thank you! I have lately been a proponent of setting transfer slots and then mixture and finally using timing to find an idle speed. I'll have to compare that to your process and see how it does.

[@leonardrice2830]

Awesome as always. I’ve been a fan of you sir since the 80s!👏

[@alessandroghizzo972]

Great video for the new year

[@stevececchele2880]

The echo filter went off about 8 minutes in. As always very informative, I always look forward to your new content. I'm a long-time subscriber and also owner of most of what you've written over the years.

[@basiclifeskillsasaman1291]

I’m so happy I found you you made my tuning so much more enjoyable thanks

[@user-ye3ty9zd2l]

Your chart on cylinder pressure and %mass burned makes sense to me. My old IC engines professor at UTexas (Dr. Ron Matthews) told me years ago that the combustion process is not from fuel and air straight to CO2 and H2O (water vapor). He told me the combustion process goes through stages of combustion, partial combustion of precursors leading to complete combustion. The same applied to octane boosters in that they slowed the formation of precursors even though flame speed is essentially unchanged. I hope I remember all of that correctly.

[@GMengineguy]

DV, always a pleasure to watch your videos and read your books! Working on Chevys built in the 60's it seems they all ran off ported advance. Most of us thought that was to improve power by increasing advance at low speeds under high loads. Thank you so much for setting the record straight!!!

[@North700]

Thank you David, I much appreciate the effort you put in these videos 😊

[@jacquespoirier9071]

excellent in depth explanation. this type of fiddling is related to an engine lab as this needs precision equipment and in depth engine engineering knowledge. excellent video

[@bd5058]

“Plucked Their Bullshit from Thin Air” 👍

[@lautburns4829]

Thanks David. Great as usual!

[@johnbrady177]

Amazing channel! Thank you David!

[@billlittle4285]

Im a big believer in using the vacuum advance even in a street blower motor, it will run cooler temps, thanks David!

[@bobwhite4344]

phenomenal vid. going to have to watch this one several more times. my little cup runneth over.

[@79beans347]

This is a great in depth video on timing, just shows no matter how much you think u know there's always more that you can learn, especially from this guy. David i still want those heads , the ones you mentioned or any of your cheaper one's that will make a 347 scream, trying to get at least 500hp

[@stevesadusky8634]

Excellent video David. 👍 Thank you...

[@richarddein6418]

Legend, I followed it to the letter your instructions. Wow.. gone from problems to no problems. Before had trouble idling in gear. No problems now! All the factory books wrong! Have understood everything and applied it. Keep helping others with your knowledge please. Have bought you holley tune book and will turn up at end of month. Total respect to you and Andy 🇦🇺

[@trivigonzales]

Does this practice Work for any carbureted vehicle or only for high-powered performance carbureted vehicle ? I have a 1949 Chevy deluxe with the two 216 in line six all original and I would love to be able to get the maximum performance out of that motor while cruising on the freeway I 55 mph is there any help you can give me or guide me into the right direction on how to get maximum performance out of my car

[@realazliving]

I’ll tell you what is in David’s books (Those I’ve read which isn’t all I’ll admit), genius, truth, and more power tips than you can remember I bet. I’ve been reading them since I was a kid and I’ve passed a half century a few years back.

[@wantkixido]

I like this man! He knows what he's talkin about. Imagine havin him for a father...incredible! Thank you, Mr.Vizard! you made somethin that is complicated and too much for many folks to comprehend , much easier to grasp...! Good luck on your subscription goals. Not that you need it ; just people who are wanting to know and good attention grabbing titles that will persuade them that they need to know and this is what they are lookin for...This is where you may need the luck! Creating titles like that may prove to be harder than the subject matter itself!!!

[@gordonborsboom7460]

This is a great start, David. 🍻Here’s to more like it.

[@DavidVizard]

Gordon - rest assured the team and I will do our best. I know for a fact that Andy has got something up his sleeve but I am not really sure what!

[@aguyinnc2865]

Thanks David and Andy. I've been working on tuning my 351C 2V in my '73 Mach 1 Mustang. It's currently all stock, with dual exhausts. It's low compression, maybe 8:1 or even less. Not a power house, but I've been trying to tune for best street performance, and good mileage. Would like to do a good street build on it someday, but that is a few $$$ away. Big cost will be better heads. Anyway, I currently have static timing at about 15-16 degrees BTDC. I put a Mr. Gasket re curve spring set in the distributor, and set the mechanical advance stop in the 10L position from the 15L. Does seem to have more punch, runs good, however it appears I do not have an adjustable vacuum can. Yes, I am running the stock distributor with points. I am currently using stock ported vacuum. I have found yours and Andy's videos very interesting. Thanks a lot.

[@michaely6665]

I bought a combi vacuum/pressure gauge, reset timing and carb using David's tips, and changed distributor vacuum from carb. ported to manifold. WOW low throttle torque and fuel burn on O2 lambda is way better! P.S. setting timing with vacuum gauge gave same results as on road testing for engine tapping I had done!

[@rayowens4355]

Thanks again for sharing your knowledge!

[@DavidVizard]

You are very welcome Ray. Have a good 2024.

[@nerradnosnhoj5122]

Thank you for the video Happy New Year !!!! Best wishes for 2024 Keep 'em coming !!!!!!

[@aparker9622]

I'm 27 with a 76 c30 and an 07 subaru impreza. I love turning wrenches and am soaking up every bit of knowledge you have. So greatful for you and and your channel. The more I learn, the more I see guys that have no idea what they're talking about

[@rickbrandt9559]

used vacuum advance for years(since1972) converted my old (73) Hd Sportster to electronic to VOES idle/mileage /accel all improved, Big Yes for vacuum, great for big cammed jet boat & street engines.

[@roberthollinshead2325]

@DavidVizard Thanks Mr. Vizard I've been reading your wisdom for years! Awesome stuff!

[@LiveChrist365]

I value your Holley Book. I've learned so much on how to tune and adjust holley carbs. My engine hasn't ran so good since from using what is in your book to modify, tune and adjust my holley 750 HP carb for my SBC 350

[@Napalms10]

I bought the book myself. It's a great book with tons of great info in it and I am not a amateur or d.i.y.

[@mikef-gi2dg]

I think I got the gist of it. I stumbled upon Full vacuum by accident. I installed a performer cam 2102 in my new GM performance 260hp 350. To get the 14 to 16 degree initial the cam recommended, and still be able to easy hot start it I did this. Set initial at a low 4 to 6 degrees, modified vacuum advance can to a limited 10 to 12 degrees, max. At idle I go the 14 to 16 degrees as recommended. It idles and cruises at 19 to 21 inches of vacuum and hot starts super easy even in 90 degree weather. I'm going to try and follow DV procedure and fine tune it all. Took me years to dump ported advance, slow learner!

[@Joeylucio22]

Awesome video always appreciate the information👏🏽

[@user-cg1jg9mi5c]

Thank's for the detail info how to set up an engine for good ideling and the most economical way

[@andredesousa96]

I learned so much from this one! I own a Mazda mx3 that comes factory with a little v6 in it, it’s my project car which I’ll try and tune-up the engine maybe get some hidden horses out of it. I’m actually waiting on some of your books to arrive. I’ll also be a Mechanical engineer by the end of July. I’m developing a great deal of respect for you Mr. Vizard, besides all the knowledge you’re also a gentleman, you and my hero Frank Zane in the fitness industry seem to carry youselves in a similar way. From Portugal 🇵🇹

[@DavidVizard]

Mechanical engineer - all the best wishes for your final exams my friend.

[@johnj2496]

Tell em david anyone who has any technical sense should clearly see by Your knowledge and even more atell Your open mind to the times where you talk about real experiences where you tested and verify X results Crap talkers will run their mouths but Everyone with any sence sees right thru it Thank you for sharing all your vast knowledge

[@cbobscountrybunker2312]

Awesome video

[@ZEPRATGERNODT]

Always good stuff

[@adeptpeasant6161]

I never knew about the Bluetooth distributors. Now that's slick 👌 Especially for power adders. 😮

[@montanakidd]

After watching and listening to this video podcast I can can see where he's coming from . U can't trust anyone who never spent any time under the hood excluding checking the oil . Plus I can't really trust a mechanic who wears rubbers on his hands ? How are they supposed to feel a tiny hole 😅😂

[@offshore50]

Here for support

[@ldtenenoff]

David so thank ytou david always enjoy and learn wen watching ur vids

[@79beans347]

I was just checking to see if you had any more of the heads we discussed the aluminum gt40 or vic jrs , c3's or anything thing that will make my 347 scream, i messaged a while back and Terry messaged me back saying that he talked to you and would let me know when he had time. He may still be busy but im just making sure I haven't been forgotten about but no big rush if everyone is busy. I appreciate your time and hope to hear from you soon with good news about some 300 cfm flowing heads 😊 thanks DV

[@nathanlee5789]

love holley , gotta get your book .

[@markcollard9326]

Nice view to thumbs-up ratio here 1 hour in. 115 views, 129 likes. Great content.

[@4ujkdguy]

DV always amazing explaining, you make something so complex as an internal combustion is easy to understand. I would love to come to one of your porting seminars, tried emailing but never got a response 😢. Léase let’s know when the next seminar is. Thank you for sharing❤

[@autonomous_collective]

IONFIRE PLASMA IGNITION REVIEWS BY DAVID VIZARD -WORLD REKNOWNED ENGINE GURU! Ex aerospace engineer David Vizard is a revered engine builder and acknowledged Chevy big-block engine expert. That's why GM contracted him to develop several engine packages for the Chevy big-block crate program. In addition to being a successful racer and engineer, he holds over 40 patents ranging from fuel additives to improved cylinder head designs use on F1 engines. David Vizard is also one of the world's most widely published automotive writers with over 37 books and 4000 magazine articles to his credit. As an engine builder David Vizard has 58 years of flow bench experience and 52 years of dyno experience having performed an excess of 500,000 dyno pulls over his career. This is a man who not only knows what he is talking about, when he speaks people listen...his engine building seminars are famous worldwide! David saw our system in action at PRI 2010 and was a skeptic until he ran comprehensive back to back tests at Terry Wallters dyno shop in Roanoke, Virginia.

[@autonomous_collective]

When it comes to any new ignition technology, the only valid proof it works, is to test it on a finely tuned test bed engine out of which every last bit of horsepower has been squeezed out. Any gains should show up by doing back to back dyno pulls with and without the plasma amplification. Any such testing would have to be carried out by unbiased racing and engine building industry professionals. Ionfire Ignition's innovative patented plasma ignition system has been tested and industry peer reviewed by two of North America's top racing and engine building gurus: David Vizard and Terry Walters!

[@DavidVizard]

@@autonomous_collective I have had good results with long burn plasma ignition but my source seems to have vanished. Where can I get a system like this?????

[@autonomous_collective]

@@DavidVizard THE IONFIRE PLASMA IGNITION SYSTEM! THE WORLD'S MOST POWERFUL AUTOMOTIVE SPARK AMPLIFIER - IGNITION BOOSTER! GAIN 10HP to 40HP AT THE FLICK OF A SWITCH!! When you tested it David, it was called: Blue Phoenix Plasma Ignition .

[@autonomous_collective]

kzbin.info/www/bejne/Z6LdqYN8aLeZhdUfeature=shared

[@jimlove4541]

Thank you David for all you do and have done. It's hard to have a thick skin when it comes to the ignorant trolls out there on the internet and You tube specifically. You are braver than I. Keep it up I look forward to your videos. Thanks Jim. Can you give a hint as to the instrumentation from England?

[@racyclark3576]

Love what you and Andy are doing that’s great but I would vote to have no music. Thank you.

[@daleolson3506]

The music sucks

[@sumguysr]

Great new intro!

[@65sohc]

I have a Progression Distributor in my 406 sbc. It would be awesome if you would create a timing map illustrating what you discussed. with respect to what some would think is extremely high advance at idle and low load conditions. I have tried to make my own and have done probably 200 iterations. It is amazing what you can do with the Progression. My engine idles at about 850 rpm at 60kpa. When the electric radiator fan kicks on it puts an extra load and tries to drop the idle so I have those cells at 50 degrees to compensate.

[@flinch622]

"...out of thin air!" Holy flying buffalo's batman! Burn rate is its own great subect, and glad to see it. And, happy new year to all.

[@michaelblacktree]

That's a good point. You don't burn holes in pistons at idle. That only happens under load.

[@geniferteal4178]

I work in training for a large company. The first thing our instructors do at the beginning of a class is explain their credentials. This tells you they know what they're talking about. I may not know in every instance but I've seen enough of your videos to appreciate your experience. If you say this is good that's bad. I know your methodical approach and where that information comes from. That's what really matters. This man came to teach our company about a particular type of product.. He had a company for 30 Years that only sold that kind of product which he manufactured. Someone asked him a question what if this happens? He said I've only seen it 3 times. ( For reference that's in thousands of installations over thirty years). No one in that room doubted him. That's how I feel about your advice. Thank you for sharing.

[@brainward2611]

I have that Holley carb book Love it !!

[@DavidVizard]

Mr. Brain sir - what can I say- you obviously have great taste!!!!!

[@curvs4me]

So goooood! This becomes even more critical in a boosted engine. David, could you delve into that as well? Say a boosted engine is running 12 degrees advance at 6500rpm with X psi of boost, timing can increase at lower rpms because the piston is moving slower even if boost remains the same. Slower speeds also give more time for detonation to occur at high load. How to optimize these events is a delicate dance for sure. I'd love to hear from experience. Lot of people won't even go near it because easier to burn it down at high torque slow speed.

[@johnd4273]

Very informative video DV. Always look forward to your videos. Would love to see you going through an engine doing the explained timing and leaning out the carb adjustment. My set up is Holley 750 DP mechanical advance only so no vacuum advance on my distributor. I wonder how this would change the set up procedure and best method of tuning?

[@ehb403]

Very useful information, thanks for sharing the results of your years of experience. I have an odd application in that I'm looking for a fast idle (2000 rpm) on a 4.6 liter 3 valve Ford V8 with moderate air density and close to stoichiometric mixture. This info gives me a bit of a start (of course I'm planning on using a wide band O2 sensor). I can't use vacuum because I'm not going to include a throttle in this application (pneumatic valve operation to control air flow).

[@cs2-llc]

Read this book at least once a month. It has been THE best and most comprehensive book on tuning Holley Carburetors. I have a 750 Holley Street HP Vacuum Secondaries on a mostly stock 460. Using this book and some of my own experience, It runs beautifully and has a clean idle. All tuned from vacuum and following getting the mixture right FIRST, then adjusting the timing. 90% of hot rudders get this totally wrong. That and running vacuum advance off of manifold vacuum. NOT ported vacuum. I am always astonished how many, so called experts, get this totally wrong.

[@midwestlee-iw8nl]

thanks good tech

[@RandallSoong-pp7ih]

Thank you Mr Vizard!!

[@theshed8802]

Looking forward to the next instalment of this series. Could you please do a short video advising everyone of where the Mission Impossible project is up too. Even though I'm a Ford man at heart, I really enjoyed the project, and was looking forward to seeing how much was contributed to the cause. Regards Greg

[@DavidVizard]

Greg, Mission Impossible progress has slowed very much due to my reduced output fron high blood pressure and chronic back arthritus. It's still moving forward but at a much slower pace.

[@theshed8802]

@DavidVizard thanks for the update David. Wishing you the best health wise. Certainly hope that you can get the blood pressure under control. Arthritis is a nasty thing, i feel for anybody that suffers from it.

[@matthewmiller2268]

David, we are holding you up in prayer 🙏. I know about arthritis with having the beginning stages of it in my knees. I found that out when I saw the orthopedic doctor for the sprained meniscus on my left knee. I definitely have tremendous respect and appreciation of your knowledge and wisdom of how an ICE works.

[@glennjohnson4064]

I thoroughly like your teaching, I've learned more in just a few videos than I have in 20 years. Like you I hate the bs, I've been giving so much bad advice my whole life and there was no reason for other their stupid need to voice their opinion. Which was all bulsh__

[@markbogle8062]

Thank you for the infor.

[@brucearterbury1856]

I hope you mention the Carb Cheater. I am considering it for my 292 powered 56 GMC

[@tomstulc9143]

What is a carb cheater. Is it for more power or fuel economy does it do both?

[@DavidVizard]

I am hoping to do a test on this about summer time!

[@EitriBrokkr]

It just electronically throttles the air going to a carb to help it more mimic the linear response of fuel injection ​@@tomstulc9143

[@tomstulc9143]

@@DavidVizard thanks you are a gracious encyclopedia of auto knowledge. I keep wondering about your 318 project. I don't see the algorithms too often bringing up your vids. Posted a little blog about running Lean of peak in aircraft engines. That's where I first learned that the myth I was taught of young that getting leaner Burns valves out of engines. I finally came to understand it wasn't the lean fuel which burned up engine valves it's because Rich fuel cooled the cylinders. In other words things are a little more complicated than it seems on the surface.

[@davej3487]

@@tomstulc9143 Not relevant to this video but... A "Carb Cheater' is a brand name device. About $400. It is basically a "CONTROLLED" vacuum leak and uses a wideband O2 sensor and a black box to control the leak. If your carb is jetted fat rich the system opens the leak under the carb on a plate and balances the mix, sort of.... Will not work if the carb is jetted lean. So when the exhaust is leaner the box shuts off the leak. Done in mili-seconds...

[@TaekwondoFitForLife]

Thank you Mr. Visard, I’ll have to re-visit this many times.. I wish to gain full understanding and add to my “in head toolbox.” Let’s say.. Thank you Sir, and especially for clearing-up the silly old ported or manifold vacuum source thing which is so silly all over the internet in discussions.. Or as you well put-it people going on about something they poorly researched and pose as “facts” … silly, I try to tell people I deal with that this man David Visard was involved in the industry when the epa stepped-in and said to use ported to lower emissions… Can lead a horse to water… right Sir?😂 Thanks again Sir! Mine is a 1963 Chevy C10 383 Stroker, thanks much for my tune!

[@cuda6496]

David at 26:38 what do you meant by "minimum" vaccum? I'm thinking for example from 20 to 18-17 on the vaccum gage?

[@stooartbabay]

Best ignition sound affects I’ve ever heard :) David, could you please please please do a BMC B series engine video? Would love to get your updated 2024 thoughts on these engines… there is a huge community of people that use them and I am sure it would help increase the number of subscribers by a huge amount. Thanks heaps! :)

[@lautburns4829]

Do you mean that Austin engine?

[@stooartbabay]

Yes, used in MGBs and Austins… but David knows this…. It’s a bigger version of the mini engines.

[@daledavies2334]

Very interesting.