Nothing speaks louder than cold, hard numbers. To give you a better idea how these heads p
Remember the old saying, Build a better mousetrap and the world will beat a path to your door? Sorry folks, but it aint always true. Take for example Don Lositos latest custom-designed Ford racing head. Losito, the owner of Ultra Pro Machining, builds CNC-ported heads for some of the top Winston Cup, UDTRA and Sprint Car engine builders in the country. His latest creation is a cylinder head for Ford engines that is capable of flowing more than 30 cfm (at 28 inches of water) over the best-ported versions of the current gold standard, Fords Yates head. Unfortunately, Ultra Pro does not advertise, and only an elite group of engine builders were even aware that Lositos creation exists.
Until now, that is.
Ultra Pros raised port, canted valve head is an ingenious blending of Fords combustion chamber with Chevrolets valve angles. After several months of research and development work on the raw casting for Fords SC1 high-port head, Losito has come up with what is quite possibly the biggest evolutionary step in Ford racing heads since the Yates head hit the scene in 1992.
Theres something magic about Fords combustion chamber. What I wanted to do was combine that with Chevrolet-style valve angles, and I thought I might be able to do that when the new SC1 casting came out, Losito says of his new head. I knew for a Ford V-8 most people run a 4.125-inch bore, so I starting looking within that parameter for the best location for the intake valve. I determined that I needed to cant the valve over to get the best flow. We tilted each intake valve 10 degrees back and also canted it three degrees to the side so it opens away from the cylinder wall and lets the air and fuel come in without being shrouded by the cylinder wall. Weve already got excellent flow from the exhaust valve and determined that we didnt need to change it.
Sure it sounds simple, but repositioning a part as important as the intake valve means rethinking the placement of rocker arms, rocker arm studs, pushrods, valve cover studs and water jacket clearances, among other things.
In the beginning when we began looking at the SC1 head, we had to determine if we could put all the new positions in it. We discovered we wouldnt break into the water jacket when we put our guide bores in, which is critical. We also wanted to move the spark plug, and we also had to determine the optimum port shape and if they would fit in it. Everything you move affects something else, so there was a lot of reworking things to make it all fit together.
In addition to the valves, Losito also made some of his own port changes. Both the intake and exhaust ports on the Ultra Pro head are raised .500 of an inch to provide a straighter shot into and out of the combustion chamber. Losito warns that raising the intake port a half inch on the already tall Ford block (a 9.2-inch deck height) can make it difficult to fit the air cleaner on an ARCA-type stock car, but it can be done. Series where the air cleaner is allowed to stick out of the hood, such as dirt Late Model, will have no problem.
This head makes a strong motor, says UDTRA Dirt Late Model ace Scott Bloomquist. Weve only run the canted valve in a few races, but its definitely got a lot of power. We dropped the track record at Iowa by over half a second. Most big engines seem like they quit pulling halfway down the straight, but with this head it just keeps going. Its definitely got plenty of torque.
Other engine builders we talked to estimated their gains at the rear wheels to be around 28hp. Lositos canted valve heads arent yet NASCAR legal, but they are allowed by many dirt Late Model and Sprint Car sanctions as well as ARCA. For Ford engine builders and racers looking for axle-twisting, track-shredding torque, this may be just the ticket.
The process begins at Ultra Pro with aluminum castings straight from Fords foundry (photo 1). Dont even think about ordering up a set for yourself. Losito has developed a unique relationship with the companys racing division as one of the top developers of CNC-port designs for everything from Winston Cup to Pro Stock dragsters.
Amazingly enough, despite the extra mass of metal available to work with by getting the casting raw, there still isnt enough material in all the right places. Because the locations of everything from the valves, to the pushrods, to the ports are shiftedand sometimes significantlyextra material has to be added before any machining can begin. Welder Jim Taylor builds up material in strategic areas using special aluminum rods. Welding to add strength while minimizing warpage is a delicate art, but once the CNC machines have cleaned up the work it will be impossible to tell where the original casting ends and the additional, welded-on material starts.
There are actually two welding sessions performed on each head. The first (photo 2) adds extra material on the corners and on the valvetrain deck so pushrod and valve pocket locations can be shifted. This first operation requires approximately an hour and a half of delicate hand work per head. In the first round of machine work much of the rough cutting is completed, including drilling coolant holes, bolt holes and removing much of the unnecessary material. Throughout the process, extreme care is taken to remove every possible variable. For example, all cutting tools wear as they are used, so all critical holes and passages are cut with an end mill in a circular motion instead of with a conventional drill bit. The size of the end mill can be recalibrated on the CNC machine as often as necessary, where a drill bit cannot.
Starting with a raw casting allows more wiggle room for moving valvetrain components, but it also means much material has to be cut away. Compare the casted port opening versus the size of the final exhaust port marked on the exhaust face (photo 3).
Three different CNC machines are used in the process because of the complex operations required. After the first operation is complete, the heads are redecked to make sure they sit perfectly flat on the surface plate before moving to the second CNC center where they are rough ported. This operation brings the ports to within .050 of their final dimensions. Guide bores and spring pockets are also cut.
Rough porting reveals just how much the ports (photo 4) and valve pockets (photo 5) are shifted to match the new angle of the valves. In the photos you can see the areas on the right-hand side that have not been touched by CNC cutting tools (they still have the rough casting surface). After this stage the heads go back for a second session on the welding table where the untouched areas are ground smooth and then filled in with aluminum. This allows for smooth, perfectly sized portsremember, ports that are too large can be nearly as damaging as too small because achieving maximum velocity of the air/fuel mixture as it enters the combustion chamber is just as vital as flow.
Before finish porting begins, beryllium copper valve seats are installed and press fit so they are virtually impossible to remove. The heads are also decked to their final height to insure the critical combustion face is true. The final machining stage is done on a special CNC machine that can move along five axis at once. And although almost every surface has been cut to within .050 of its final dimensions, each head spends between seven to eight hours on the machine.
It takes so long because we use such tight tolerances, Losito explains. We limit transition lines to .0225 where a lot of people use .050 and .060. It takes twice as long, but on the track you see a difference in consistency in the way the engine runs. We dont get any tool deflection or port deviation because were hardly taking any metal out per pass. Also, we make two rough cuts on each port before we are ready for to do the final CNC porting. Our final rough port leaves .005 for the finish port, so there arent any marks from tool chatter or other irregularities. Incidentally, Ultra Pro does not recommend hand polishing the ports because that can introduce deviations into the heads.
The valve seats can be cut to a customers specifications, but most leave Ultra Pro with a 50-degree cut on the intake and 50-55 on the exhaustwhich has been proven to allow better flow in high-lift heads. Dave Mitchell cuts seats with a careful eye on a dial indicator (photo 6) to make sure the seat depthand combustion chamber sizeis consistent for every head. Unless the customer specifies otherwise, most heads leave Ultra Pro ready to receive 2.180 inch intake and 1.625 exhaust valves (the intake can be as large as 2.200).
Finally, every head is tested on the flow bench and pressure tested before going out the door. Darrick Vaseleniuck, who normally operates the flow bench, says he rarely gets a head that tests outside Ultra Pros rigorous parameters. Notice (photo 7) the modeling clay Vaseleniuck has molded into a venturii around the entrance to the intake port; this mimics the characteristics of the intake manifold and gives a more accurate reading.
Boxed up and ready to go, each head, which started the process as a 52-pound chunk of aluminum, weighs in at a svelte 34 pounds. Now that he has all the mechanics of the head working dependably, Losito says hes also working on a lightening program he expects will shave approximately four more pounds of dead weight off each head.
The Total Package Obviously, with a head as radically different as Lositos canted valve piece, a racer cant simply bolt on a pair and expect to tear up the track. The shifted anchor points of the valvetrain means Losito had to create a unique valve cover to fit the head. Special intake and exhaust flanges are required to fit the high ports as well as take advantage of the heads extra capacity to flow the air/fuel charge. The rocker-arm system is also custom made by Jesel to fit Lositos requirements.
Charlie Long, engine builder and owner of Charlies Automotive (You can see some of Longs engine-building handiwork in Cookin Up Some Power, Circle Track, Nov. 01), has used the heads in ARCA engines and has some suggestions for tuning the overall package. That head flows so much better than most heads, you can run a cam with a little shorter duration, he says. Aim for about four degrees less duration on both the intake and exhaust than you would normally run.
Larry Clark, the engine builder for Scott Bloomquists UDTRA cars, also has recommendations for any engine builders looking to use the head: Its a powerful head, and we still havent had enough time with it to unlock all of its potential. Dirt Late Model cars are very sensitive to power curves. The first engine we built was somewhat explosive and could be hard to drive on slick surfaces. The best places for Scott to use it right now are tracks that are heavy and can really use power. Then its a rocket ship.