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.
ASCS rules say that the first...
ASCS rules say that the first portion of the port up to the "ASCS" stamp in the runner can be worked, so Roush Yates developed a CNC program specifically for these heads to maximize airflow.
Here's an interesting problem...
Here's an interesting problem just for Fords. Sprint Cars spin the external oil pump off the nose of the camshaft using a hex adaptor. But the timing gear bolt on a Ford goes through the center of the cam. To fix this, Roush Yates drills and taps all the camshafts with three bolt holes (Chevy style) along the perimeter so that a hex adaptor can be installed as you can see here on the custom camshaft from Comp Cams.
Most Sprint Car motors use...
Most Sprint Car motors use a gear drive timing setup, but Anderson says their tests have proven that gear drives can transmit power-robbing harmonics. Anderson uses a timing chain setup for the Fords using Roush's Hy-Vo timing chain. It is hard to see here, but it is much heavier duty than the standard double roller timing sets most of us are used to. It needs to be because it not only spins the camshaft, but also the five-stage oil pump, the power steering pump, and the fuel pump.
This is the inside of the...
This is the inside of the timing cover which is cut from billet in the Roush Yates shops. It utilizes a tensioner (the white "finger") which takes the whipping motion out of the timing chain that can happen when the driver stands on the throttle. This should help stabilize the valvetrain even further.
The billet crank is right...
The billet crank is right out of the Cup program. The short 3.400-inch stroke slows piston speed at TDC, which helps build cylinder pressure during combustion and, in turn, makes power.
Roush Yates went with a Jesel...
Roush Yates went with a Jesel aluminum shaft-mounted rocker system which should provide maximum stability. Lash adjusters are included (unlike Cup rockers) to ease maintenance. The pushrods are 3/8-inch one-piece units with 0.080 wall thickness.
The lifter bores are opened...
The lifter bores are opened up from NASCAR-mandated 0.875 inches to 0.905 to accept solid roller lifters. Notice the aluminum tops which help keep the weight down on these trick lifters while still giving them enough height to clear the lifter bores.
Most Sprint Cup motors don't...
Most Sprint Cup motors don't use a damper, but Roush Yates uses one after finding it didn't hurt power and helped smooth things out. It also provides a place to etch timing marks which makes accurately setting the ignition timing much easier. The damper, by the way, is the same one that Roush Yates has used in its Nationwide Series plate program.
Anderson installs the magnesium...
Anderson installs the magnesium intake and fuel injection system from Engler.
One difference Anderson mandated...
One difference Anderson mandated for the fuel injection system is to move the injectors from the outside of the runners (which you can see are plugged in this photo) to the inside. This requires welding on new bungs, but it points the injectors directly at the back of the intake valves and helps keep the fuel atomized as it enters the combustion chambers.
Anderson said one of the goals...
Anderson said one of the goals was to make the engine system a complete unit to make life easier for racers. For example, the oil tank is attached to the engine as you can see here, so everything can be removed as one unit.
The five-stage external oil...
The five-stage external oil pump is driven off the camshaft. For simplicity, all stages scavenge from the oil pan, unlike the Cup engines which dedicate a stage to scavenge oil directly from the lifter valley.
Here's a shot of the water...
Here's a shot of the water pump, which attaches to a cage off the timing cover and is driven by the spinning damper.
The plumbing you see here...
The plumbing you see here is a pressure line that feeds cool oil to the valvespring oil squirters.
The Dyno Sheet-Engine builder...
The Dyno Sheet-Engine builder Jeremy Anderson was admittedly a little hesitant to hand over the dyno sheet for Roush Yates' new Sprint Car racing engine. "I've spent a lot of time building Cup engines, and it's hard to get used to sharing this information we used to consider top secret," he says. Still, we have the numbers in our grubby little hands, and now we're sharing them with you. The averages were 607 horsepower and 504 lb-ft of torque.