This all came to light about three or four months ago when the Saintys' first asked me for some help. I tried, but a couple of things didn't respond to my changes and it made me delve into exactly why their deal doesn't work.

Any nitro mechanic can do a couple of basic things and if one doesn't work, you do this, you do that, and at the end if it still doesn't respond and give you a direction then you have to start asking yourself why, because that answer may give you a reason. I wasn't aware of this until I started to help them and I realised why their motor doesn't respond.

The big reason the four-valve overhead cam design is so excellent is that it moves a lot of air and doesn't require a great deal of valve lift to move the air because you obviously have two valves in and two valves out, it allows you to put the spark plugs away from the heat, therefore shrouding them and allowing you to run in a very lean condition, for example with gasoline, in Formula One, or an Indy car.

I'm talking here about endurance gasoline or alcohol where high heat and fuel economy are what you're aiming at, and let's face it, all your European and Japanese cars are looking for that 15:1 air/fuel ratio, 80 miles per gallon type of deal. That's a great deal. You've got great horsepower, a spark plug that will live in that environment, and everything is aimed at a high heat, normally aspirated situation.

Okay let's take the same design and throw 55 gallons a minute of nitromethane through it; it doesn't work. Why? The reason is all those things that make it work with gasoline or alky on an endurance set up is what the nitro drag race motor detests.

That is a spark plug that is out of the action, stuck away in the corners which allows the fuel to puddle back in there, which will drag heat from the plug, and give it the opportunity to ground the spark because nitro is conductive. The spark will actually go through the molecules of nitro if they're packed close enough together, as in a puddling situation, and the spark will go right through the fuel without jumping the electrodes and creating heat to begin the combustion process.

All this is fine when you have two speeds and very low volume, but you start getting high volume and all of a sudden you have so much fuel and air in there that you get puddling and you can wipe out the heat very quickly. It can get cold really fast because there's so much fuel volume to drag the heat away, and if the heat doesn't build it will just get worse and worse and worse.

And yet it can go the other way with so much fuel and igniting so quickly that once you start to get heat in there it will start to accelerate and go into a detonation condition, where the spark plug will glow red and ignite the incoming mixture as soon as the intake valve closes because the plug is glowing. It becomes a glow plug.

With a nitro motor you have to make it go for, let's say, five seconds, you're hoping four, under wide open throttle without detonation occurring. So therefore it must cycle, it must have a power stroke, and then it must have a cooling stroke, an exhaust stroke, an intake stroke and another power stroke.

All this is to achieve one goal, and that is fill the cylinder with fuel, ignite it at the correct time to produce pressure so it is useful to the crank stroke. In other words it peaks on pressure after top dead centre and the piston is forced back down the bore, therefore pushing the crank around, turning it into flywheel horespower.

If this doesn't occur the flywheel won't spin because you will get peak pressure occurring early in the power stroke and then because combustion has already occurred it wants to push the piston back down the bore and wants to stop the flywheel.

You get a couple of cylinders doing that and all of a sudden you go from a free spinning flywheel to bugger all. That's not making any usable horsepower, because the power is going to destroy itself. You've just made a machine to destroy itself because the timing of your cycle is off.

With a four-valve motor the spark plugs are stuck in the corner, and that's the only place they can be. And the problem is if you get them close to the valve seats you have a physical problem of getting the spark plugs in and out of the motor and the valve covers and everything if you get them very close in there all they will do is love the intake and exhaust seats and they'll create a pathway and just burn the seats right out. Dale Armstrong had that problem when he went to the McGee. They had to put stellite seats in and they could never get the exhaust seats to live.

What happens is the spark plugs have to be cooled on overlap. The overlap cycle on a nitro motor is a whole lot more important than anyone understands. It must make sure that the exhaust cycle doesn't come back up into the intake and cause the incoming mixture to ignite, thus producing a bomb with a backfire. You must have enough fuel in your inlet manifold blowing through to physically push the flame out.

If it doesn't do that it blows the blower off, hence lean motors backfire the blower. Why? The reason is you didn't have any "cushion" fuel there. This is a physical phenomenon of nitro. You must have enough cushion fuel to push the fuel out of the exhaust. Also that cushion fuel must run over the spark plug and cool it to prevent it becoming a glow plug.

That's one of the reasons why the current nitro motors love volume and cycle on volume, because part of the cycling makes the spark plugs able to still be hot enough to vaporise the fuel around them and light it easily. It must maintain a gaseous form because you can't light liquid nitro. You must have enough heat in the chamber and around the spark plug for the fuel to be in a vapour so that when it does spark it will be when you want it to. If it doesn't do that you've got a bomb.

With the four valves-per-cylinder motors the spark plugs are shrouded in the corner because of the physical dimensions of the motor, such as in the Sainty motor. If they get hot there's no way to cool them. They all light and will idle with no problem because you don't have this radical heat build up, but as soon as you step on the gas it will either accelerate its heat to where the plug is glowing and goes into detonation, or it will put the flame out.

If it has any kind of puddling at all immediately a pocket of fuel builds up around that plug because it gets pushed up in there. That's why the Hemi chambered engines have worked so well. With a square chamber like a pent roofed four-valve you have these pockets where the liquid gets puddled and then it just starts this grounding effect and it won't recover from that.

So then it goes into a dropped cylinder situation and it will not get past it. Forget it, you have to cool the motor down, and start all over again. You'll be lucky to get it to cycle, then you'll go into a detonation situation because you don't have the cooling cycle to work properly for you.

What I'm saying is that the four valves-per-cylinder motor doesn't want to cycle with a high volume of nitro. It may have done it in the two-speed days with the single plug in the middle of the chamber, that design works fine, but with dual magnetos you have to get the plugs right by the exhaust seats.

It will cycle, because let's face it, your intake and exhaust are very close so you get the cross-flow over the plug but you have to get it so close to the exhaust seat to get it to work that it now wants to burn up all the time because it's too close.

There's no happy medium, and if it's close enough you have a problem with the seats on the exhaust just becoming a glow plug at the same time. Now you've got double the detonations. It becomes very, very hard to make that motor cycle to make enough horsepower to generate the crank flywheel cycles to spin to maintain RPM for the clutch to do its deal so that you get a decent ET.

What we're doing here is to get the engine to run for five seconds under a wide open throttle with full nitro, full boost and keeping all the heat buildup within limits. A motor has to start at a certain temperature and it's got to finish at a certain temperature.

It has to start at X-degrees and finish at X-degrees. In a perfect world it would start at X-degrees and finish 10 degrees hotter. If you got perfect combustion all the way through there you would probably make maximum horsepower. We always have to tailor our fuel curves so that the temperature doesn't rise too abruptly.

It seemed to me that the four-valve motors don't want to react like that because all the cylinders are not cycling in unison because of all the physical problems, and then when they do cycle you just have to get the temperature to rise gently all the way down the track so that it's reaching its peak just before the finish line, and it's very hard to have all those eight "guys" on your side.

You have eight "soldiers" there that all have to be on each other's side, yet they're all fighting against each other. One little abrupt rise in heat and all of a sudden that one goes into detonation. Then it's over and you get this damage occurring.

The four-valve motor is not fiendly to what we are trying to do to it here. What Stan Sainty has done now is build a three-valve engine which gives you two intake valves, which is a lower cost motor because you can use stainless valves and not titanium and you can still put the spark plug close to the exhaust seat and yet you haven't got two siamesed exhaust valves that have a problem burning the middle of both of them.

Since they have eliminated that problem Sainty's engine potentially may be the best of both worlds. It's better than having two exhaust valves because that doesn't work. With two intake and one exhaust, with the spark plugs like a Hemi they'll still get washed with the cross-flow.

This isn't a rule of thumb, but I worked it out from looking at Sainty's engine, and knowing how a nitro motor is supposed to work and knowing the evolution of why we are where we are. Armstrong tried a Ken Veney head that had spark plugs moved out aways to try and stop the plugs burning, but that was a lean motor combination and it fell on its face. That showed him that spark plug positioning is absolutely paramount.

I have been around many people who have tried stuff in the chamber and they've all fallen on their faces, things such as valve size. They tried bigger valves and the motors didn't run. What does that tell you? It tells you that the amount of heat leaving the chamber is important. It needs to retain some heat for saturation of the heads, pistons, rods and block and yet needs to get rid of excess, so the valve size and lift are important. All this is to make it cycle.

You don't see perfectly running nitro motors here or in the USA. They're perfect for a while but you have to jockey them into position all the time. You always have a problem with the siamesed cylinders inside getting too hot too quickly and the outside ones being cold.

I can remember when a couple of guys in the US tried to have light weight cylinder heads where they hogged out the ends of the castings. The outside cylinders burnt up immediately because they had less material to saturate and they got hot around there. It upset combustion and it wouldn't cycle.

You know what they ended up doing? They filled them back in with material. They lost their cycling because they lost their heat build up. The heat buildup became radical where it reached a point of saturation. They could have staggered all their nozzles and carried on but they decided there was absolutely no gain.

So everyone's been on this cycling thing. A 300 mph run is not going to be made unless a Top Fuel dragster or a Funny Car will be cycling at maximum efficiency through the lights at the RPM that's desired to make that rear gear ratio turn those wheels fast enough to record that terminal speed. It must cycle.

You take it for granted that an alky or gasoline motor will cycle, and they naturally do that, but when you get into nitro sometimes these pigs refuse to cycle, and it brings home what naturally occurs and you take for granted. It makes you delve into what makes horsepower and what makes these motors cycle, how you can pour nitro in a fuel tank at the front of the car and pull the chutes at the other end and have transferred that liquid into speed and power and heat energy.

It really is fairly wild what we do. We transfer this liquid into horsepower and many things must happen to make that occur. The gasoline guys don't think about that, you top the tank up, you make a run and you come back and, okay, it went 8.66 at 164 mph. There are many factors that make that liquid fuel transfer to heat energy and finally into the rear wheel speed to make sure that car went down the track.

We are at the forefront of technology with Top Fuel dragsters. We have actually gone back to the basics on cycling and that's what has made these motors a lot more efficient. You have a four valves-per-cylinder motor and all of a sudden it won't run and it won't cycle and it brings back all of the little lessons you have learned along the way about the Hemi.

Let's face it, if they were better everyone would have one, but it's not. Isn't it funny how the key to simplicity is the key to good design? The Hemi design is a simple two-valve motor, with two spark plugs right together, close to the exhaust but not so far for it to be a glow plug situation and a hemispherical chamber and a flat top piston and it makes unreal power, because it is the right furnace to burn the fuel.

It's just the right shape, and not only is the furnace burning, you can open the door, shove the coal in there and not get your shovel burnt. Everything's just right for it to happen.

Let's face it, if you opened the door and shovelled the coal in there and it burnt your shovel and it got red hot and you put it into the pile of coal and the coal caught fire your cycle of shoving fuel in the furnace will be off because your shovel is too hot. It's as simple as that. That puts it into perspective. That's what makes four valves-per-cylinder motors a bad design for what we are doing.

They may work in a perfect world. The McGees have got a four second run out of theirs, and hats off to them. I would say that they are absolute geniuses and brilliant in making that motor do what it did. They jockeyed, they robbed Peter to pay Paul, they got it to do it but they already know that it's a lost cause. It's not the way to turn liquid nitro fuel into horsepower, there are too many things against it.

The Saintys have found the same thing and they're going to be making a motor that is cheap to run, cheap to build and still make that liquid fuel cycle into heat energy and produce rear wheel speed and I think that it will be a success because of what they learned doesn't work.