Fine-tuned cooling system components help NASCAR and Indy 500 racing teams nose out the competition.  Oil temperature is one of the most critical engine parameters in an engine with up to 700 horsepower. These NASCAR engines can develop temperatures as high as 245%F.  C&R Racing (in Indianapolis, of course) is the world's largest supplier of radiators and oil coolers to NASCAR race teams, making parts for cooling engines in prestigious racing series' like Winston Cup, Busch Grand National, NASCAR Craftsman Truck, and more.

C&R's engine oil cooler, exchanging oil heat through the engine's radiator coolant, is more efficient than air-cooled models, which also include a drag-producing duct into the cars' aerodynamic lines.  But, sometimes, C&R's oil cooler is just too darn good!

"That becomes a problem," says C&R owner Chris Paulsen, "because the engine oil temperature can fall  below the optimum for top engine performance.  Since we can't lower the coolant temperature," Paulsen explains, "we had to devise a variable bypass valve that would still keep a constant total flow of oil through the valve."  There were no stock controls available that would guarantee an even oil pressure, so Paulsen had to design it himself.  He decided on a barrel-type rotary valve with 100% flow rate through an infinite adjustment range, from all oil through the cooler to total bypass directly back to the engine. 

Oil coolers and radiators aren't the only prestige racing parts sporting the C & R logo.  If you follow the NASCAR circuit, you're likely to see their Mastercam-programmed logo on a car's radiator.  Many winning Indy 500 and NASCAR drivers have ridden with C&R parts programmed with Mastercam.

Riley and Scott, whom you may know as one of Indianapolis' premier race car builders, rely on C&R for fabricated aluminum transmission bell housings with large aluminum plates totally contour-milled with large pockets and windows machined by Mastercam- generated toolpaths.  

C&R also machines and fabricates suspension mounts for Riley and Scott rear engine cars from the builders' IGES files.  Paulsen notes that "Mastercam makes it really simple and fast to get a no-waste toolpath for a complex part."  

The Plymouth Prowler, America's first production street rod, uses C&R-made, Mastercam- programmed suspension pickup points that Riley and Scott fabricated into their front end assemblies for the prototype of the unprecedented Chrysler Corporation presentation.

     Indy car maker Reynard Racing Cars, Ltd. sends SimCAD-drawn IGES files for suspension parts, steering arms and various contoured aluminum mounts and brackets to C&R.  Also files for parts to fabricate the shrouds that keep the heat of braking away from race car wheel bearings.

Paulsen designed the four main pieces of the oil bypass valve -- aluminum body, barrel, cover plate, and adjusting handle   in AutoCAD.  Paulsen brought the files into Mastercam, which C&R has been using since 1994. "The program (developed by CNC Software, Tolland, CT) has such a  wide range of options, it was the logical choice for toolpath generation," says Paulsen.  In fact, he adds, "There's a Mastercam influence in every C&R part riding on winning NASCAR and Indy 500 cars."

"We wanted a good looking piece, since racing television coverage often includes engine shots," Paulsen continues, "and every ounce of material counts against a race car, so we wanted to radius all the corners."  After programming the outer contour to be  cut with  a 3/4" 2-flute end mill, "we went right back on the same toolpath," he says, "this time specifying a 5/8" radius corner-rounding end mill."

Next, Paulsen used Mastercam to circle-interpolate the barrel bore, a 1.300" diameter by 1.100" in depth, and, with a Z-axis offset on the same center line, a 1.975" diameter pocket  to be counterbored to a depth of .187" to register the barrel's cover plate. He also programmed the channel for the main O-ring seal on the main axis.

Before any cutting was done on C&R's Protrak mill, C&R machinist Joe McCauley was able to check his programming using Mastercam's solids-based toolpath verification feature.  The program runs each toolpath on a piece of virtual stock, allowing programmers to avoid possible gouging or tool damage, saving time, material and cost.

McCauley changed tools again to center drill and tap a 4-hole pattern on the cover bolts and machined a slot for the pin which would eventually limit the arc of the adjusting handle.  Standing the part upright, he completed the valve body's three oil ports -- one input from the engine oil line, and one output port each to the cooler and directly back to the engine.  They were drilled  and tapped and an O-ring slot milled, one port at a time, to accept and seal -12 AN fittings.  The output ports terminate at the barrel-bore circumference in the unique, broached "double-D" configuration that gives the valve its constant flow property.

McCauley turned the valve barrel on C&R's Protrak lathe, and then milled the Y-shaped oil channel.  Next, he drilled-and-tapped the hole for the knurled handle retainer thumbscrew.  Paulsen programmed and verified the hex of the handle stem in Mastercam, then ran the toolpath on the Protrak.

Programming the cooler's adjusting handle toolpath in Mastercam was easy.  Paulsen drew the 3-D file in AutoCAD, and imported the file into Mastercam in IGES.   With a few selections of parameters from Mastercam's machinist-friendly graphic interface, he set it to work creating the most efficient toolpath for the smoothest result.

This toolpath was also checked using the program's solids-based toolpath verification function.  "We do that with all parts," Paulsen says, "because it makes it so easy to check everything as you go along."  The handle's broad outer contour stepped up to a more rakish profile for the hand-contact surface of the handle, leaving a base flange which accounted for about a quarter the .500" depth of the piece.  A ball-end-tool fillet gave the handle the typical C&R flourish, while the slim contour helped reduce the racing weight of the part.  A 3/8" hex broach for the barrel stem and a tapped hole with its 6/32" handle-travel stop pin completed the part.

The valve cover plate was disk-turned on the lathe and the screw hole milled using Mastercam once again.  "It's so easy to plot out the hole that way... center the drill, drill, tap the holes... programmed all at one time."  

The finishing touch to the whole unit -- the step that makes the part look like a NASCAR- level class act -- was done with Mastercam finesse, too.  After all exterior parts surfaces were black anodized (the adjusting handle in flaming red!), C&R's logo was loaded into Mastercam, which wrote the toolpath for a tiny cutter to incise the design into the cover plate, right below the operating arc of the handle.  As you can see in the photo, the whole effect does C&R... and NASCAR... proud. While C&R can't boast of direct endorsements from top drivers like Dale Ernhardt (Richard Childress Racing), Mark Martin driving for Roush Racing, or Morgan-McClure  Motor Sports' Sterling Martin, Chris Paulsen and crew know that they know C&R parts have helped them win.  And now we know that Mastercam has helped C&R become the name behind the top NASCAR performers.   

     CNC Software, Inc./Mastercam can be reached at (800) 228-2877 or (860) 875-5006, 344 Merrow Road, Tolland CT 06084.  Or visit Mastercam's Web Site at