In a previous article (read here) we introduced you to world-renowned technical expert David Vizard. This month we extract as much knowledge from him as we can!

Last month we spoke with David Vizard about the who, what, when, where and how he became a key player in the production of V8 DIY manuals. We’re still amazed at how an English accent muscled its way into the realms of America’s Holy Grail, but once again we won’t dwell on this point, just marvel at the tenacity of a person who infiltrated that closed society.

David mentioned last issue that he didn’t hold opinions; instead, he reckoned his dyno defines answers to all our performance related questions. It would be great to have unlimited access to this type of equipment, but in the real world, unless you’re seriously committed to making your hobby a business, mills, lathes, a dyno and airflow benches are out of financial reach.

That’s where David steps in. As long as you believe he has taken testing to its conclusion, then owning his literature (or reading it) is as good as having a workshop full of specialist equipment.

Gone are the days when selecting a cam meant going to the bottom of the page in a Crane or Isky catalogue. David’s testing of those 23,000 cam combinations mentioned last month pretty much says it all. If there’s another person out there with that much experience in valve timing, we’d love to meet them. And just to reiterate his experience, although it’s not widely known, at any given time David has upwards of 50 record-holders running round using his specified cam sequences.

It’s not just the speed equipment industry that uses his expertise, either. NASA had him on its payroll calculating the amount of fuel it would take to economically arrive at the moon. We’d say there was little room for error on that particular project…

He’s played with unobtanium in the realms of Formula One. (“We worked on pistons worth 50 grand a piece back in the 1990s,” he says.) At the same time he was making valves weighing nearly one-third of an equivalent titanium item. For those who have never held a piece of titanium, the best way to describe it is to think of picking up air in the shape of a valve, then realise Vizard was working with a material significantly lighter than that.

Back to his ‘opinions versus dyno-proven, definitive answers’ comment last month. We thought you’d like to hear his responses to a few off-the-cuff questions. It became apparent that David’s knowledge base isn’t just limited to results from the dyno. Well, in a way they are, but he’s made lots of mistakes along the way while drawing his conclusions.

“People think I’m cleverer than I really am,” he says. “My real talent is recognising ability in the people who surround me.” That goes back to his days of working in the labs at Smiths Aeronautical during the 1960s. “If you have friends with a wealth of knowledge then invariably the answer won’t be far away.”

So let’s get on with the questions — watch for his opinions versus facts.

NZV8: What performance cars take your fancy at the moment?
DV: Rather than nominate any particular car, look at the Holden Monaro. It isn’t being produced any more but what a beautiful machine, it drives great. The Americans took all the character out of it when they developed it into the Pontiac GTO and never recouped their money. Unfortunately, the ‘not invented here’ syndrome took hold and that was the end of a mean machine.

NZV8: What’s happened to all the tech articles you’ve produced for magazines over the years?
DV: Let me tell you, the internet and its forums have severely affected monthly magazine sales. The editor of a very well known American magazine told me recently at the current rate of decline he can tell you the day it will close its doors. Right now, I can’t even give away a tech article to an American magazine because they can’t keep their own writers busy. It’s totally different with the book business though; my publisher, Cartech, has me topped out for the next two years.

NZV8: How long does it take you produce one of your manuals?
DV: Well, the latest edition of How to Build Horsepower — the manuscript, the photos, the captions, all 148 pages of it — was produced in exactly five weeks and five days. The funny part about that is my publishers gave me a deadline of six months, I told them it would be done in six weeks.

NZV8: What effect has Popular Hot Rodding’s Engine Masters competition had on the hobby?
DV: It doesn’t produce real engines for the everyday speed merchant. However, Jon Kaase has won many of the Engine Masters competitions and it’s done wonders for his business. As far as giving followers an honest and level playing field to judge engine builders and tuners, it does wonders. But remember, most of the engines for this competition are built fragile and to run for a very select period of time.

NZV8: What are your thoughts on Chinese products?
DV: They can be anything from an okay product to an absolute mess. At this point in time I have no objection to someone taking their own invention to China to produce, but if it’s copied stuff then you need to ask yourself do you want your big block to have equipment made by a company that doesn’t even know what a 454 is? Or would you rather have it made by somebody who lives, eats and breathes engines and gauges every failure as a slight against his name? My advice to anybody who has a conscience is not to buy a rip-off copy. Remember, the end user also gets what he pays for…

NZV8: Do you think it’s time the aftermarket industry needs some form of regulatory body to keep out rogue products?
DV: Contrary to what some may think, the speed equipment industry is a very small family. If somebody puts out a new product on Monday and it doesn’t work, then pretty much everybody knows by Friday. In some ways an ISO compliance could be good for the industry, but SFI covers much of the safety and performance certification for motorsport already.

NZV8: What will be the next big performance breakthrough?
DV: What we’re going to see is the ever-increasing efficiency of superchargers. Eaton Superchargers has just come out with a new screw vane that literally puts it in the realms of a turbocharger. A positive displacement blower that emulates the performance of a turbo but without any lag, everything under the bonnet and easy to install. The turbo guys aren’t going to stand still, they’ll bring out units that are electrically controlled and more effective. I was talking to a friend of mine who’s testing the new Magnuson street blower, and he’s got it on a true street motor making 1176hp [877kW] and nearly 1355Nm of torque that will have a one-year or 12,000 miles [19,300km] warranty on it.

NZV8: Thoughts on engine-building software?
DV: They range from horrifically bad to near perfect. Guys like Kirk and Kevin from Performance Trends have made great home-user software, but then there’s the likes of Belfast University that’s producing software valued upwards of $50,000. Unfortunately, it’s cheaper for an enthusiast to go along to one of the Engine Masters teams and have them build one for them.
My suggestion is if you want something that will tell you if you’re going in the right direction, then Performance Trends programs will show you what you need to know.

NZV8: What’s been your biggest disaster?
DV: I’ve had plenty. Remember, you learn as much if not more from your mistakes because it forces you to investigate further. I like to think I’ve made them on behalf of the readers, and there’s where the true value is in my books. My leaning is very biased toward the reader. In saying that, I had a doozy of a disaster just recently. It all boils down to everybody thinking somebody else had checked the block. What started out as a hot street build ended up close to full race. Somehow we all overlooked the fact the block hadn’t been sonic tested, but I was in charge so it was my fault. It was on the dyno and we were on the last pull when the whole side of the block broke away. It had good rods, good pistons, nice crank, the lot — everything ended up on the floor. All because I hadn’t ticked the right boxes on my build sheet. That engine ended up costing me around $25,000.

NZV8: What do you think of Rhoads lifters?
DV: They’re the variable duration lifters — to get them to work is incredibly difficult. The bottom line is for the most part, if you have a stiff cam that is short to give you the bottom end you will make the top end using these lifters. At the end of the day, if you’re having to use Rhoads lifters and they’re working then you quite probably have the wrong cam.

NZV8: And zero gap rings?
DV: They leak. They have no gap but they leak. I’ve run them and they’re better than regular rings but I’ve got a lot of dyno figures to say they leak. I run Total Seal in all the cup motors I build.

NZV8: Octane boosters?
DV: I have the patent on one of the most successful octane boosters so I am a bit biased. It’s expired now because I did it in 1980. When it was tested against the others, it came out number one, it blitzed them. Ford Motor Company used it in 1982 in the Mexico Rally and it boosted its fuel’s octane from 76 to 96 octane in the Cosworth engine.

NZV8: Do oil additives work?
DV: Well, once again I’m a bit biased as I have done testing on a product called Oil Extreme. It’s available here in New Zealand through my friend Graeme Dobbe, just in case anyone’s wondering. The thing about this product is I knew the guy who created it through common friends. It was the first comprehensive test I was paid to produce. I now have pot-loads of the stuff lying around my shop all the time. The engines don’t drop off using it. It can be in one of my mules running 15 pulls a day, and once it’s broken in I can baseline the engine at the end of three months of testing and it will replicate that first pull.

NZV8: Hypereutectic versus forged pistons?
DV: Hypereutectic pistons have a high silicone content for better expansion and stability for street use. A forging will give you more protection against really lean mixtures, but provided you don’t put the engine on kill then the hypers will work better in a street car.

NZV8: Somender Singh grooved combustion chambers?
DV: That’s a good one… I have not touched a set of heads with them, but a good friend of mine did a basic test and called me up and said: “You know what, I can’t sit here and say they did work, but I am sure they did not not work. The results are encouraging enough to do more tests.” I’ve talked to a lot of engine builders about Singh grooves and the general consensus is they can’t find a reason why these will work, but tests are not conclusive. On average it seems we’re a little better off doing them than not.

NZV8: Are performance coatings worth it?
DV: There are a lot of engines out there with friction and thermal barrier coatings that are winning races. Cylinder heads are becoming so efficient nowadays the only way you can make improvements is better thermal management. There’s a coating I use on valves that acts like a graphite film and allows them to slide down the seat more effectively. One of the noticeable things when using this coating is you can even see a small improvement on the starter motor when it’s cranking over. You won’t find a Formula One team that hasn’t made extreme use of coatings.

NZV8: High-volume and high-pressure oil pumps?
DV: If everything’s right then you don’t want any more pump than is necessary. I turn my Cup engines to 9800 and they have 60psi oil pressure at those revs and they idle around 20psi. A high-volume pump is a good idea for somebody who is not sure and they have too much money invested to take a chance. I tell people if they are worried about it, use a high-volume pump; it will cost you five horsepower [3.7kW] but it’s better than costing you the engine. An experienced engine builder will know what pump will work just by the clearances. If you run loose, then thick oil and the bigger pump is the way to go, but it’s the opposite when everything is tight.

NZV8: Restricting oil inside the engine?
DV: Definitely control the oil to get the job done and no more. But for an endurance setup we’re using oil squirters that literally flood the valve covers. We don’t use that system in sprint or drag engines, but for long distance or on the street then it’s imperative to keep the valve springs cool. The only way to do that is by getting oil to them.

NZV8: Any secrets to bore and stroke combinations?
DV: Big bore, short stroke every time. Any time anybody wants to argue with me on this, they can pay me to come out and prove I’m wrong. I did a project for Chrysler in which it wanted the widest power band possible. The engine made power from 400 to 8000rpm — it made 85 per cent of its peak torque at only 1500rpm, you did not need a gearbox. Here’s the thing: that engine had massive intake valves and massive bores but just a 66mm stroke. It was the most flexible car they had ever tested.

NZV8: Do cryogenic treatments work?
DV: There’s more than something there. We’ve had it on every moving part and pushed items to their limit. After cryo treatment they’ve gone 75 per cent further before they failed. We’ve never had it make a part worse. Admittedly, other times there has been no difference, but on average it works.

NZV8: Solid roller cams on the street?
DV: If you get the right one you’ll love it, if you get the wrong one you’ll be pissed off with the noise and maintenance real quick.

NZV8: Balancing an engine?
DV: Definitely overrated. That doesn’t mean you can just put an engine together without thinking about it. Balancing V8s is far looser than we’re often led to believe. If you’ve got all your rods and pistons and the balance is back to 30 grams you’ll never feel it when it’s running. If someone doesn’t know what the balance is, then it’s a good idea to get it checked. But if you’re making a change and the weight of the pistons moves by 10 grams, don’t panic about it.

NZV8: Honing at home?
DV: I used to do it all the time, but it all boils down to having the right equipment to measure what you’ve done. I used to take five hours to do an engine; nowadays with the right equipment and torque plates at your local machine shop, it’s easier to take honing to them.

NZV8: Aluminium rods on the street?
DV: If you were to use one of those 10,000rpm aluminium rods on the street it’s going to fail at 200,000km. But if you’re going to use an aluminium rod over a steel one, then yes it is going to fail way before an H or I beam. It’s most certainly doable for a weekend cruiser or warrior.

NZV8: Sleeving blocks?
DV: It just depends on the block. My rule of thumb is one sleeve per side maximum, and they must not be adjacent. Sonic testing will tell if your block will take them.

NZV8: Cross-drilled cranks?
DV: Basically they’re overrated. Modern computer technology has shown cross drilling inevitably only allows oil out one hole, potentially causing a dry spot on the opposite side of the journal.

NZV8: Lapping valves?
DV: When you have a $50,000 Serdi machine like I have in the shop then it’s not required. But very so often I will go through and lap the valves to see where they are. I do use a grit that is so fine a Scotchbrite will wipe the witness marks off, though.

NZV8: Stale fuels: fact or fiction?
DV: Sometimes stale fuel makes more power. We actually made fuel artificially stale for a turbocharged engine and got 25hp [19kW] with no other changes. But the bottom line is this: for most normally aspirated engines, if you have your fuel around unsealed or with a large volume of air above it, then aromatics will evaporate. Please remember though, this subject is way overrated by people who sell stale fuel additives. I don’t think you’ll see me doing any tests on fuel stabilisers any time soon.

NZV8: That’s it for now David, thanks for allowing us to bleed you for info. Where can readers get hold of your tech articles and information?
DV: Until recently I hung out on the gofastnews.com forums answering questions, but presently I’m moving over to Moto Tech magazine’s forum. Anybody wishing to view or ask for advice should head over to these websites or wait for the next series of seminars, and remember, the only dumb question is the one you haven’t asked.

Interview: Cameron Sharft

Click here to read Part 1 of the interview with David Vizard.

This article is from NZV8 issue 63. Click here to check it out.