The introduction of a new “control” engine for the ARCA series that was designed, built and marketed through the highly respected Ilmor Engineering affirms the racing community’s commitment to lowering a team’s operating cost; but this action once again comes at the expense of the independent engine builder’s livelihood and racing’s quintessential spirit of continued innovation to go faster with each race.
The 396ci LSX-based V8, which made its first public appearance at PRI, will be an optional engine for ARCA teams starting in 2015. There’s no argument that it’s an impressive powerplant with considerable development in the lab and extensive validation time on the dyno and at the track. Ilmor leveraged its global resources and 30-year success record in Formula 1, IndyCar and even MotoGP to work with high-end suppliers and design a 700-horsepower engine with 500 lb-ft torque that will run to 7,500 rpm with ease and last between 1,200 and 1,500 miles in competition before a refresh is needed.
We’re not in competition with ourselves. We want something that will last a long time.–Dave Dixon, Ilmor Engineering
Ilmor had been a supplier to ARCA teams years ago but dropped the program due to escalating costs.
“We actually got out of supplying engines because it wasn’t cost effective for the teams and we couldn’t justify charging the money for what it was,” remembers Dave Dixon, director of operations at Ilmor.
Asked to build new engine
A few years later ARCA approached Ilmor about the possibility of configuring an engine for the series and eventually producing it. The program announcement was made in August 2014 with a number of prototypes build for analysis the following month, including time on the Spintron. Extensive simulation runs were conducted on the dyno with track tests held at Talladega and Salem. Ilmor was taking orders in October and started delivering engines in December.
The engine is not required but any team running ARCA-approved “built” engines may be subject to intake and rpm restrictions relative to the performance of the Ilmor 396 to ensure parity among the teams. Cost for each Ilmor 396 engine is $35,000 with rebuilds ranging from $10,000 to $15,000, depending on replacement parts. Each car is also required to purchase a $5,000 installation kit with the headers, fuel components, etc. The engines are sealed and banded and only Ilmor can perform rebuilds or service the engine at the track. Ilmor also downloads the calibration for the EFI and spark before each race and uploads all relevant data from the race so the support staff can observe engine operation.
The engine is based on a Chevy Performance LSX block. An aluminum block was ruled out after observing problems in another series that uses an alloy-block spec engine. Also, the teams wanted an engine of similar weight to the existing packages so the chassis setup didn’t have to change. Internals include a Callies 3.600-inch-stroke crank, Diamond 4.186-inch-diameter pistons, 6.2-inch connecting rod, Crane Cams camshaft, Johnson hydraulic roller lifters, Trend pushrods and LS7 rockers with Crane trunions.
“The rotating components are not super lightweight,” says Dixon. “They don’t need to be. We’re not in competition with ourselves. We want something that will last a long time.”
Working with Holley
The cylinder heads and intake manifold are from Mast Motorsports. The castings are fitted with 1.600 Inconel exhaust and 2.050 titanium intake valves from Xceldyne. Single valve springs are supplied by PSI. Under the crankcase is a Dailey Engineering dry-sump pump and on top of the manifold is a Holley throttle body and fuel system.
“We worked very closely with Holley,” adds Dixon. “The ECU is a version of the HP that’s made for us because there’s a lot of capability in the system that’s not required. Again, it’s a cost point.”
Nicknamed the ACE, or ARCA Control Engine, the Ilmor 396 carries a 500-mile warranty provided the teams don’t run outside certain parameters, such as oil pressure, coolant temp and rpm. The engines have to go at least 1,200 miles before they can be returned for a rebuild, unless the season expires. Each rebuild renews the warranty. Of course, some teams may be in a position to throw the warranty out the window.
“Say they’re losing water with a couple laps to go but they’re in a position to win,” says Dixon. “Racers are going to want to win the race.”
Finite racing life
The first rebuild will cover basic consumables, such as pistons, rings, bearings, valve springs and possibly intake valves. The second rebuild on a particular engine my include valve seats, lifters, rocker arms and other similar parts. For the third rebuild, the camshaft and connecting rods will get a close inspection.
“Obviously racing parts have a finite life,” explains Dixon. “On some of these parts, we just don’t know yet. But we’re pretty confident the crank and rods will last longer than they would in a Cup-based engine.”
Since the teams purchase the Ilmor engines, they can sell them to another team. However, Ilmor would prefer teams not part them out when the useful life has expired or if the team folds. Ilmor will buy back engines with a pro-rated offer. Again, the company’s goal is to make the Ilmor 396 the engine of choice in the series. But unlike the NASCAR-approved LS2-based 364ci spec engine developed by Robert Yates Racing Engines for the K&N Pro Series and profiled in this EngineLabs story, Ilmor intends to keep all the assembly and rebuilds in house. Under the Yates program, engine builders can purchase the approved and specially encrypted parts, or Yates will build a turnkey engine. Ilmor never considered the option of certifying engine builders for the refreshes.
“Trust me, I’ve been on the end of that frustration myself,” says Dixon when asked about the loss of work for independent shops. “From the inside you’re always against that sort of thing. But when you realize the potential for cost savings and the fact that ARCA fields were steadily declining because of grossly escalating costs, something had to be done.”