(CONCORD, NORTH CAROLINA) – Boosting horsepower for increased speed requires an engine that can breath deeply. However, to do this requires technically advanced machining equipment and the talent to apply both the art and science to engine building. Both are evident at Penske Jasper Engines in Concord, North Carolina. The results were evident in the winner’s circle at the NASCAR Daytona 500.

Powered by Penske Jasper Engines, Ryan Newman (No. 12 Alltel, Penske Racing, Dodge) and Kurt Busch (No. 2 Miller Lite, Penske Racing, Dodge) blew past Tony Stewart for a 1-2 Penske finish at the 50th Great American Race in early February. It was Roger Penske’s first Daytona 500 win as an owner.

Anybody who is familiar with high performance engines knows that the key to making horsepower is having a properly designed cylinder head with ports that flow air and fuel very efficiently to produce a good burn pattern in the combustion chamber.

Engine builders that change the stock ports on a cylinder head call it porting. Porting a head refers to fine-tuning the shapes of the ports that direct airflow to and from the cylinders. To improve its porting process, a manufacturer of high-performance heads for racing engines will use a multi-tasking machining center that is capable of both milling and turning.

Often racers use solid aluminum billets to machine custom heads. For motorcycles a Pro Stock drag racing cylinder head starts out as a block that weighs 68 pounds. After machining, they weigh only 12.5 to 13 pounds. For racing, both motorcycle and auto racers try to eliminate as much extra weight as possible. But at the same time the heads have to be durable. Wall thickness between the outside of the head and the ports has to be constant for proper heat retention and cooling. Ports also need the right surface finish that eliminates or reduces flow turbulence and allows the air/fuel mixture and exhaust to move quickly through them for more horsepower. Also creative undercutting in the ports is what separates the champions from the average racer, and it takes a very advanced machining center like a Mazak INTEGREX e-series machine to do this.

To get these unique curves and finishes in a cylinder port, often requiring both art and science, they are sometimes done using a three-axis machining center and an add-on tilting table. Then finish work is done by hand to get them closer to the perfect airflow state.

But by using a multi-tasking machining center like Mazak’s INTEGREX e-series, production can be significantly boosted while the unique shapes of the ports remain consistent with minimal hand operations and easily repeated by downloading a program.

NASCAR Connection

For the 2008 NASCAR racing season, all the major engine builders have built new engines. Although the rules only allow an engine displacement of 358 cubic inches and specific parameters for engine block deck height and cylinder bore spacing, there might not be much that an engine builder can modify.

“But there’s plenty,” says Jerry Soots, machine shop supervisor for Penske Jasper Engines in Concord, NC. “Cylinder heads, ports, intake manifolds, camshaft timing, and much more can be changed to give a racer that leading edge.” All of which involves precision machining.

Penske Jasper Engines builds engines for Roger Penske’s NASCAR Sprint Cup teams (Kurt Busch, Ryan Newman and Sam Hornish, Jr.).

To get the edge that these engines need to be winners, Penske uses Mazak equipment that includes an INTEGREX 300Y Multi-Tasking machining center, VTC 200B vertical machining center, VTC 510C/50-II Vertical Machining Center, and a QUICK TURN NEXUS 200-II CNC Turning Center. Penske Jasper Engines builds approximately 200 to 250 engines a year, including rebuilds.

Production runs of various components can run from 50 to 100 pieces. By making their own components, it allows the company to be much more flexible in designing an engine for various race conditions, including short tracks, super-speedways, and intermediate tracks of varying conditions.

For example push rods link the rocker arm and cam shaft, helping drive the valvetrain. Different tip lengths will affect intake and exhaust levels. “We purchased push rods at one time,” Soots says. “Now we make them ourselves, which helps drive a lot of prototyping and R&D efforts.”

Other components made on Mazak equipment at Penske Jasper Engines include power steering reservoirs, power steering caps that vent air buildup, rocker stands, seal housings, oil pan dividers, and many more.

Engine Porting for Power

NASCAR engine builders realize that cylinder head porting is a crucial means to gaining the additional horsepower for a winning engine. But as mentioned, it takes advanced machining centers to do this.

Mazak’s INTEGRX e-410H II excels in cylinder head porting. It permits full five-axis milling and has a 12,000-rpm/30-Hp advanced milling spindle that tilts up to 240 degrees. Not only does this provide unsurpassed flexibility for machining complex parts, both the B-and-C axis can be positioned in increments of 0.0001 degree for superior accuracy and finish.

For tooling, a lollipop cutter accomplishes the milling and high-tolerance finishes deep inside the curving channels of a cylinder head port. In fact, “fine-tuning the interior shapes of the engine’s curving channels that direct airflow to and from the cylinders can be done in a single setup,” says Mazak’s Jack Halenkamp. “Where other machines typically run this kind of work in the 60 to 80 inches-per-minute range, we programmed the machine at 120 inches per minute and ran it very successfully at 100% override. Where a cylinder head can take anywhere from four to seven hours, we were finish-machining them in just over two hours.”

Robin Cave, Mazak’s national applications engineer, says, “The INTEGREX e-series design gives the machine’s milling spindle the freedom to move like a machining center can move - with a box-shaped work zone permitting the same full field of travel at the machine’s top or bottom. The INTEGREX e-series is essentially a machining center effective for turning.”

It’s capable of cutting from various engagement angles along the inside of a complex channel. The 12,000-rpm spindle speeds permit a diamond-coated version of this tool improving machined finishes significantly compared to more conventional 6,000-rpm or 7,000-rpm machines.

Also addressing simultaneous five-axis machining on the INTEGREX e-410H II is the new MAZATROL MATRIX CNC. Software and hardware advances in the MAZATROL MATRIX include powerful internal computing speed to support 16 million pulse-per-revolution encoders on each linear axis for high-accuracy, sub-micron resolution in both EIA/ISO programs and Mazak’s MAZATROL conversational programming. Powering these advances is a new 64-bit twin-engine CPU that produces feedrates for machining complex surfaces two times faster than the previous CNC control.