Ask the average performance enthusiast about Ford's modular family of engines and you'll usually hear a barrage of preconceived and misguided notions. The engines are too small. Those things don't make torque. You need a blower to make power with one of those. The bore is too small for real horsepower. Ford blew it when they phased out the good old Windsor small-blocks. The opinions go on and on, but the reality is that the mod motor, introduced in 1991, has been one of the most successful and innovative series of V-8 engines in production history.
To serve as a foundation, Kaase started with a production Ford M54A aluminum block as a ba
Notable for its single or dual overhead cam layout, the mod has been produced in two-valve, three-valve, and four-valve variations, with iron and aluminum blocks, and in a staggering range of displacement and horsepower output. It is safe to say that the mod has been offered in a broader range of permutations than any engine in history. There is little debating the mod's success as a production engine. Still, outside of modifying late-model vehicles, suspicion of the mod seems to linger in the hot rodding world.
When we revised the rules for the 2013 AMSOIL Engine Masters Challenge, one of the changes from previous competitions was to remove the prohibition on four-valve engines. We wondered how many would take note of this revision, and take up the mod as the basis for a competition build. From a classic engineering standpoint, the advantage of a four-valve layout has been documented since the early part of the 20th century. Still, we had to wonder how common misconceptions might influence the acceptance of the mod engine in our competition. After all, this was a contest of normally aspirated power, one where low-end torque is a major contributor to score, and finally there was the hurdle of a 400ci minimum displacement. This is not the normal venue of the mod Ford.
Jon Kaase of Jon Kaase Racing is an engine builder known for innovative thinking and exceptional engine building talent. Kaase saw opportunity in the four-valve Ford, "I started thinking about it right after the rules were announced last year at the press conference at the PRI show. It just looked like if you could make it big enough, it would be an interesting project. I thought it could be very good, but I wasn't sure, since I didn't know that much about them or what parts existed. I started to do some research, because I didn't have any history with that engine whatsoever."
Factory six-bolt cross-bolted main caps are standard equipment for these blocks, giving bu
Job one was to explore the possibility of increasing the displacement to meet the 400ci requirement. Kaase explains, "I really didn't know how much stroke you could put into one, since nobody really had taken these engines to this kind of displacement. I had to see if big displacement was physically possible, but in the end it turned out to be pretty easy."
Kaase began by looking at block selection, considering both the iron and aluminum blocks available. Determining the iron blocks to be more limited in bore size, Kaase went with an aluminum 5.4 production block as the basis. Kaase elaborated on the block: "The aluminum block has siamesed cylinders, and does not come with a sleeve in it. It comes with a thin plasma coating as the liner in the cylinders. I bored it out and designed some thin .050-inch wall sleeves for it, and ended up with a bore size of 3.720 inches." Kaase had a custom billet crankshaft cut by Bryant, using the OEM journal diameters and a 4.700-inch stroke. Filling the bores are custom Diamond pistons built from a model made by Kaase for this application, with Eagle 6.658-inch rods connecting the internals. The combination yielded a displacement of 409ci, making it the largest known engine of its type ever built.
Exotic Top End
Kaase retained the stock rod length, but opted to upgrade to Eagle H-beam rods. The piston
Clearly, the defining component of the engine is the four-valve DOHC cylinder head arrangement. Ford had several variations of these four-valve heads, with these being the Ford GT-style castings. Kaase actually acquired this set from Roush Yates, as takeoffs from a Daytona Prototype endurance racing engine. The heads were already CNC ported, and Kaase actually acquired two sets, giving him a set of heads to experiment with. As Kaase tells us, "I worked on one of the sets putting a little bit bigger intake valve in it. That is the set of heads I ended up running, but I really didn't see much improvement. To be honest, I did hardly any headwork, almost nothing. I did put the bigger valves in, but the other heads made every bit as much power."
The heads and cams were essentially a team, and optimizing the combination required unique considerations with the DOHC arrangement. Unlike a conventional pushrod engine, the DOHC engine opens the door for a wide range of variables and adjustments, with separate intake and exhaust cams allowing experimentation on centerline angle individually. Kaase described some of the theory and testing, "With all the valve area they have, at about half lift there is a lot of valve opening area, so these engines will run about 20 degrees less camshaft. If you can run a lot less camshaft, it would seem to reason that it would make a lot more torque down low. With the very long stroke and the short camshaft, I figured it would be very good down low if it had the right manifold. Really, these factors influenced my decision to try the four-valve in the competition."
The crown configuration of the Diamond pistons was duplicated from a model made by Kaase t
Even with a giant stroke of 4.700-inch, Kaase considered the block clearance modifications
The GT-style heads are actually takeoff units from a Roush Yates endurance racing program,
Jon continued, "I talked to COMP Cams and they helped me out with ideas on the duration. I had two different sets of cams, and in the end had one set reground, so I had quite a few variations to try out. I tried a lot of different things, and it is basically trial and error. I started out with the biggest cams, and I had those cams in every possible position, with wide lobe separation, narrow separation, way advanced, way retarded, just everywhere, because they are easy to move. It was pretty consistent that the intake wanted to be at around 98 degrees centerline, and when I finalized everything, the exhaust was the same, it wanted to be at 98 degrees. You can say I was at 98-degree lobe-separation angle, and zero advance. One observation I made from the EFI cam sensor, which reads in degrees, is that from 3,000 to 7,000 rpm the cams will retard about 5 or 6 degrees. You couldn't ask for anything better than that, it is just what you want."
The key advantage of the four-valve is that virtually the entire chamber is used for valve
While the four cams seem exponentially more complex, Jon tells us, "It wasn't that hard. For this contest the intake lobe is going to want to be between 92 and 100 degrees. That will work the best, especially with a compression-ratio limitation. With 11.4:1 compression, the engine still produced about 240 to 250 psi cranking compression, which helps down low. At the same time, the later you open the exhaust the better off you are going to be down low, so having the exhaust in at 98 degrees it opens late and that helps you. It wasn't that hard to figure out; I knew about where it wanted to be and that's about where it ended up. On these kinds of engines especially with their good exhaust flow it wasn't going to need a lot of exhaust cam. Initially I had less exhaust than intake, but I ended up with them both the same."
Nothing really outlandish was needed in the valvetrain; the factory Ford components proved to be excellent. As Jon explained, "The rockers have a roller wheel and 1.8:1 ratio, and it really works out well. I never had any trouble with the hydraulic adjusters. I tried shimming them and making them almost solid, and it really didn't matter, they worked fine no matter how you did it. In the end I just ended up removing the limiters and running them as original. I never had a bit of trouble as you might have with a hydraulic. With these engines the spring loads are much more modest than we are used to with the larger valves of a pushrod engine. I used COMP Beehive springs with loads of 115 pounds on the seat and 280 pounds open. If you look at the valves they really weigh very little and they have titanium retainers on top of that, so the relatively light spring loads offered all the control required in this operating rpm range."
The DOHC mod uses a long chain from the crank to drive the exhaust cam, with a short chain
The induction system consisted of a factory '00 Mustang Cobra R intake manifold with an Accufab throttle body. This rather rare intake manifold is a two-piece unit, with laid-over individual runners enclosed in a separate plenum housing. Kaase found this intake to offer the broadest powerband, "When I first got it running, I had a four-barrel intake manifold, and the engine made as much as 2 hp per cubic inch. The thing is, for the EMC competition you need to have very good low-end torque to score well, so it goes to show you that even with everything else going for you, with one wrong component, it still will not give the power curve you want. We had to give up a lot of that upper-end power to make it better down low."
Jon continued: "The manifold is a two-piece design and is hard to find, especially the top. On the bottom I ported it a little bigger, but I don't know if that really mattered because I started out with it un-ported and when I ported it, it didn't really help it. It is pretty small, but it still makes pretty good power. The biggest thing I did to it was shorten the runners a little bit, because they were really close to the sides of the top cover. There were a few places where the entry to the runners was a half inch from the top cover. I cut about an inch or more off the runners and angled them back. I made radius entry rings out of aluminum plate to give the runners a good entry. The shorter runners really helped from about 4,000 rpm and up, mostly because the stock runners were just too close to the top cover wall."
The induction development continued with the fuel injection, as Jon details: "The other thing I did is experiment with the injector position. When the injectors were in the original position, there was only about 5 lb-ft of difference, but 5 lb-ft is the difference between a win and loss at the AMSOIL Engine Masters Challenge. With the injectors in the stock position, it was easier to get the tune correct, and you could see it was clean in the plenum. When I moved the injectors up the runners like I ran them, you could tell it had more standoff, and you could see the fuel staining in the plenum. It was much harder to tune, and I had to really chase the fuel curve for each cylinder through the rpm range, with the greatest difficulty being below 4,000 rpm. We tried it with the injector at the mouth of the runner, but it didn't work out well. The pulses would throw the fuel out of the port and it would go everywhere."
The mod uses roller cams with a large base circle, and feature balance counterweights. The
Kaase retained the full production valvetrain, including the hydraulic lash adjusters and
With the plenum removed, we gain a peek inside the intake showing the radical cross-ram de
While the Kaase mod motor is an extraordinary piece in just about every aspect, the crowning achievement has to be the unique "16-pipe" exhaust headers. The system takes advantage of dual primary tubes from each cylinder, a setup we confess to have never seen on any V-8 engine. Kaase tells us, "I got the idea looking at a Buell V-twin racing motorcycle. At first glance, seeing the four pipes I presumed it was a four-cylinder, and looking closer I realized it was a twin. It was a system that I felt could be put to use on the Ford four-valve. I had only built one set of headers decades ago, but something like this was interesting enough to try. My first set was based on the idea of using a long and a short primary on each port, looking to produce a wider tuning window, but it didn't really work out compared to a conventional header. The final design proved to be functional in testing, showing advantages at certain rpm points compared to a more conventional header. Actually, there were quite a few further variations I would have like to have tested, but the time was not available. You could play around with something like this forever."
Kaase had high praise for the FAST XFI injection system. With the distribution difficultie
There's no doubt that Kaase's mod motor is an unusual engine combination. With a displacement bigger than any other V-8 mod motor, a huge stroke and tiny bore, four cams, 32 valves, 16-pipe primary headers, a factory intake with injectors shooting up toward the plenum, all based on a stock Ford block and heads, and turning an essentially factory valvetrain, this thing was an enigma. At the 2013 AMSOIL Engine Masters Challenge, Kaase's radical mod held a crowd of onlookers simply slack-jawed at its sight. That astonishment continued as the engine went into the dyno test cell and began spinning out power. At the bottom end, the numbers were staggering, with over 600 lb-ft of torque on the dial at just 3,400 rpm. That, folks, is an outstanding level of torque for an engine of this displacement. The dyno's strain gauge kept stretching up to a peak of 666 lb-ft at 5,100 rpm. The resultant specific output of 1.63 lb-ft per cubic inch is unheard of, especially considering an 11.4:1 pump gas engine. Convinced that a four-valve mod can indeed make torque?
On the power side of the equation, 720 peak horsepower was recorded, equally impressive considering the engine was built for the broadest possible power curve at the EMC competition. Kaase had already seen well over 800 hp in pre-event testing with a combination favoring top end output. Still think you need a blower to make power from one of these mod Fords? Think again. Frankly, the Kaase mod gathered up all of those preconceived notions about these modern Fords and annihilated them in an incredible display of pure engine power, taking his fifth AMSOIL Engine Masters Challenge Championship in the process.
|By The Numbers409ci Ford Modular Four-Valve
||custom COMP Cams hydraulic rollers
||230 degrees at .050
|Rocker and ratio:
||COMP Cams 1.8:1
||Total Seal .043, .043, 3mm
||custom forged by Diamond
||OEM production aluminum 5.4 M54A
||Eagle 6.658 inches
|Intake valve diameter:
|Exhaust valve diameter:
||VP Fuels VP100
Kaase experimented with injector position, looking for an edge in power. The final arrange
Is it jewelry or a magic power trick? Kaase tells us his one-of-a-kind 16-pipe header syst
What may go unnoticed is the level of detail that went into making this not only the world
|ON THE DYNO 409CI MOD