Based on NASCAR Sprint Cup...
Based on NASCAR Sprint Cup architecture, Roush Yates Engines' new motor for Sprint Car racing looks to be a winner.
Ever wondered how NASCAR Sprint Cup technology would translate to other racing series? Yes, hot rodders with deep pockets have been putting old Cup motors in their cars for years, however they've always been detuned to make them more manageable on the street.
But what about applying all the tricks Sprint Cup engine builders have learned to another class of race cars where all-out performance is still demanded? Despite all that technology, how would it hold up to racing on dirt tracks? Or can these engines, which are routinely rebuilt after every race, withstand a season's worth of punishment?
Interestingly, a number of factors converged in the right time and at the right place so that we can find out. Roush Yates Engines currently builds all the race engines for every Ford team competing on NASCAR's Sprint Cup Series. It also builds Ford engines for the Nationwide and Camping World Truck series and has recently branched out into several other non-NASCAR racing series such as USAC.
Roush Yates also leads the way in the development of Ford's new FR9 race engine that is scheduled to see competition on racetracks by the time you read this. The new FR9 engine uses a completely new block, crank, cylinder heads, and even intake, so that means Roush Yates is facing a large inventory surplus when the new race engine is phased in.
The solution, of course, is to find racing homes for many of the components that still have useful racing miles left in them. The aluminum cylinder heads, intakes, and valve-train work well when mated with aluminum Windsor blocks to make big-inch Dirt Late Model motors, but that leaves the short-deck, cast-iron blocks with no home. At least, that is, until Roush Yates engine builder Jeremy Anderson volunteered his time to help a buddy rebuild is Sprint Car race engine.
"That engine was a Chevrolet, and the guy was competitive," Anderson says, "but as I was going through the engine I kept seeing ways that we could make it a lot better. In a lot of areas it was 15 years behind what we were doing with Sprint Cup race engines."
After that rebuild, Anderson felt he could build winning Ford Sprint Car engines based on the components used in Roush Yates' Cup program. It turns out that the Windsor block and short-throw racing crank are a near-perfect fit for 360 cubic-inch Sprint classes using American Sprint Car Series (ASCS) style rules. So Anderson developed a brand-new Sprint Car motor using a NASCAR Sprint Cup block, crankshaft, connecting rods, and more.
The foundation for this 360ci...
The foundation for this 360ci Sprint Car engine is a Ford Windsor block raced in NASCAR's Sprint Cup Series. Engine builder Jeremy Anderson says the 358ci Cup blocks are the perfect foundation for a 360 Sprint Car motor with the final dimensions coming in at 4.0935 inches for the bore and 3.400 for the stroke.
"We put our first motor together in February of 2009," Anderson says, "and it was competitive right away. But we stuck with what we have learned from decades of Cup and Nationwide Series racing, so much of the development had already been done, in a sense."
And the proof that this engine is effective in 360 Sprint racing came quickly when Sprint Car driver Chuck Hebing won an Empire Super Sprints race in one of the engine's first outings.
"That win was gratifying because Fords haven't been a popular engine choice in Sprint Car racing in a long time," Anderson says. "And this is a way racers can get a motor that's more than competitive against what's out there for a great value. This new Ford motor makes really good power, and it has a flat power curve that makes it very forgiving with gearing choices."
Dyno results are included here, but the big number is 715 horsepower at 8,500 rpm to go along with an incredibly flat torque curve, very similar in performance to the Roush Yates motor in Project DLM. Anderson says that the engine should be able to maintain those power levels for a complete season of racing between rebuilds-after all, the Cup motor was designed to last for a 500-mile race plus practice and qualifying.
As you can guess, we were quite intrigued by this new motor and jumped at the chance when Roush Yates' own Doug Yates invited us to take a closer look. It is definitely a very interesting piece, and one that should be capable of producing victories. Take a look at what we found . . .
Another part of the extensive...
Another part of the extensive prep of the block is drilling oil galleries in order to install oil squirters aimed at the underside of each piston. The steady stream of oil helps pull heat out of the lightweight pistons. Also, all the casting surfaces have been completely polished to improve oil flow back to the pan, remove stress risers, and eliminate the possibility that a piece of slag can break loose and score a journal.
The cam tunnel is cut for...
The cam tunnel is cut for a big 55mm camshaft. High-rpm engines use stiff valvesprings which can cause a standard-diameter camshaft to actually twist and throw off the valve timing events. Roller cam bearings are also used for extra protection.
The Pankl connecting rods...
The Pankl connecting rods are hard-coated along with the pin, and the big ends have been resized to make sure they are round. The pistons are a custom forging from CP with a 10.5cc dome to provide approximately 15.0:1 compression. Notice that the piston has been hand buffed to remove any potential heat risers that could cause detonation. Finally, the ring lands are cut for a 1mm, 1.5mm, and 3mm ring pack. Anderson says they are pricey at around $600, but they are worth it because they significantly cut down on parasitic friction.
One of the nicer features...
One of the nicer features of the 6.0 inch long Pankl rods are the EDM-cut holes which send oil to the wristpins. This prevents galling in a dry-sump oiling system and also allows the elimination of a bronze pin bushing to cut weight.
The cylinder heads are ASCS-spec...
The cylinder heads are ASCS-spec Windsor heads. They've been outfitted with titanium valves from Del West sized at 2.080 for the intake and 1.600 for the exhaust. They've also been chromium nitrided for improved wear characteristics. Roush Yates has cut the decks to get the combustion chambers down from 64 cc's to 54.
Valvesprings are high-end...
Valvesprings are high-end PSI units held in place with titanium keepers, which have also been coated to dramatically increase their service life. Anderson says the valvetrain was chosen based off of NASCAR Nationwide Series R&D and works well across a wide rpm range.