0
Select Articles

Speedy Design PUBLIC ACCESS

Engineers Have to Make Changes on the Fly to Keep Race Cars Up to Speed On the Track.

[+] Author Notes

Associate Editor.

Mechanical Engineering 122(01), 60-61 (Jan 01, 2000) (2 pages) doi:10.1115/1.2000-JAN-5

Abstract

Engineers must make changes on the fly to keep race cars up to speed on the track. Westcoast, based in Anaheim, CA, designs and manufactures specialty components, mainly for the internal combustion engine industry. Engineers design the fixtures that hold the engine block in place during tooling in the same computer-aided design (CAD) program that they use for the block itself. Racing league rules prevent Nissan from changing key parts of the engine design, like the distance between the cylinders, but the company can vary other elements of the engine, such as deck height, oil passage diameters, and the main bearing journal diameters. By working out machining variables to ensure that production will go smoothly and quickly, Westcoast manufactures parts at the lowest cost possible, with no wasted production time. Westcoast is currently designing and manufacturing the most recent engine block upgrade, which will be ready for a spin around the track in May.

Article

When designing engine blocks for use in the Nissan Infmiti Racing Team race car at the Indianapolis 500, engineers need to carry out design and manufacturing changes at speeds that rival those of the cars themselves.

Though it is called a block, the foundation of an automobile engine is not shaped like a simple cube. This, of course, makes design and manufacture that much more complicated, and these factors are compounded when engineers design the powerful engines that propel Nissan Motor Co.’s Infniti Indy Racing League cars.

League rules limit how much a race car engine can deviate from the engine of its production vehicle. In this case, the production vehicle is the Nissan Infmiti. But engineers still have plenty of leeway in modifying engine design. And in the world of high-speed racing, design modifications come at lightning speed. All these factors make three-dimensional computer-aided design very handy—and often necessary—in Indy racing engine block design, according to Bob Zantos, president of Westcoast Performance Products.

The engine block for Nissan’s Infiniti Indy cars goes through a series of design changes each season; engineers must be ready to make them at any time.

Westcoast, based in Anaheim, Calif., designs and manufactures specialty components, mainly for the internal combustion engine industry. Nissan contracts with Zantos’ company for production of its racing engine blocks. From the time Westcoast and Nissan switched from twodimensional to 3-D design, shortly after the contract began, the companies have managed to slash engine block production time by about three-quarters, Zantos said.

The design of this race car engine—which generates 740 horsepower, can run for hours at 10,000 revolutions per minute, and takes the car to 230 miles per hour—is more complex than the design of a typical automobile engine, Zantos added. The Indy Racing Nissan engine generates more than three horsepower per cubic inch. Output from the Nissan Infiniti production engine is closer to one horsepower per cubic inch.

Two years ago, when Westcoast began its Nissan contract, engine block designs came to the company from Nissan in Tokyo as 2-D drawings. But engineers at Westcoast quickly talked Nissan executives into designing the blocks using 3-D CAD renderings, Zantos said.

“You can’t see everything, like bolt patterns, in 2-D, no matter how many cross sections you make,” Zantos said.

For Westcoast, another advantage of receiving 3-D CAD models is that the company’s engineers can use the digital solid model of the engine block part as a substitute for the real thing, Zantos said. That means Westcoast can use the 3-D computer model, rather than an actual model, as the foundation when establishing machining processes. Such processes include developing the tooling, verifying tooling interfaces, and setting up the computer-aided-manufacturing process.

After switching to CAD design, the company doesn’t have to wait to get a casting of the model back from the pattern maker before designing the tooling that will manufacture the parts and the fixtures that will hold the parts, Zantos said. This saves valuable time—often at least three weeks—in an industry where turnaround times need to be bested as often as racing times.

“With the engine blocks, tooling is an extremely complex issue,” Zantos said. “But one of our strengths is that we’re able to design the casting, and then, while the casting is being manufactured (which can take three to six weeks), we can design and make the fixture that holds the casting in place because we have all the part specifications as part of the solid model.

“Nowadays, you can do such extensive assemblies in CAD that you can see how everything will fit together before you make it,” he added. “In the process of creating the model, we think about how we’re going to machine it to make it as manufacturable as possible, so we can machine it in the least possible operations.”

For design, Nissan and Westcoast use Pro/Engineer CAD software and Pro/Manufacture CAM software from Parametric Technology Corp. ofWaltham, Mass.

CAD design doesn’t stop with the engine block. Before the casting design is released to the pattern maker, the Westcoast quality assurance and engineering departments hold meetings to discuss the manufacturing process. Then the solid models and drawing are sent off to the pattern maker.

At the same time, the engineering department begins to design the fixtures needed to machine the block.

The engineers use the same CAD program to design the fixtures that will hold the casting while it’s being machined. The engine block and the fixture models are then sent to the numerical control programming department, where employees write the programs that will dictate the CNC machine’s moves as it machines the castings.

By this time, the first castings have usually arrived from the foundry. Only then is an actual casting placed on the fixtures and run through the machining program.

The fixtures hang on what’s called a tombstone frame. Because engineers design the fixtures in their 3-D CAD programs, they can create layout designs that ensure as many fixtures as possible can be mounted on the tombstone frame at once.

‘‘This saves tool-change time because you’re changing fewer tools at once,” Zantos said.

By working out machining variables to ensure that production will go smoothly and quickly, Westcoast manufactures parts at the lowest cost possible, with no wasted production time, Zantos said.

Engineers design the fixtures that hold the engine block in place during tooling in the same CAD program that they use for the block itself.

Grahic Jump LocationEngineers design the fixtures that hold the engine block in place during tooling in the same CAD program that they use for the block itself.

The machining process before Westcoast started using the CAD program took three to four times longer than it currently does, Zantos said.

Nissan often revises engine block design, even after it has sent final design versions to Westcoast for production. According to Zantos, changes from Nissan can be “fast and furious.”

Racing league rules prevent Nissan from changing key parts of the engine design, like the distance between the cylinders, but the company is allowed to vary other elements of the engine, such as deck height, oil passage diameters, and the main bearing journal diameters.

The pace of these design changes in the racing industry encouraged Zantos to nudge Nissan toward 3-D design. Frequently, Nissan engineers change designs following a race, after they’ve studied results.

“The customer is working on developing more and more horsepower all the time,” Zantos said. “They’re always saying, ‘We have testing on Friday, so we’ll tell you on Monday what to change.’ ”

For instance, the first Nissan engine block produced by Westcoast put out just over 630 hp. The next engine produced 700 hp and weighed 36 pounds less than the original model. And the succeeding model was 21 pounds lighter and reached 740 hp.

Because the solid model is readily accessible, design changes are made quickly, Zantos added.

“If you have everything set up right, you change the model and that changes the machining,” he said. “The whole thing can happen very quickly—in one afternoon.” Reconfiguring just one small part of the solid model immediately triggers appropriate changes to all affected areas of the part, Zantos said.

Often, a change to the engine also requires one to the fixture. If a hole moves closer to the edge of the engine, for instance, designers need to shorten the clamp in that area.

In addition, modeling in 3-D reduces the risk of misinterpreting a design. When 2-D designs were shuttled between Nissan headquarters in Japan and Westcoast in California, the pattern maker had to interpret drawings to make the wooden forms used to sand-cast the engine block. Inaccuracies in the casting, even if slight, would carry through into the machining of the engine block.

“We work with excellent pattern makers and it’s surprising how accurately they can shape a piece of wood using the information on 2-D drawings,” Zantos said. “But it’s still not as accurate as taking a CAD model directly into a CAM program and cutting the pattern with a machine.”

Westcoast is currently designing and manufacturing the most recent engine block upgrade, which will be ready for a spin around the track in May.

Copyright © 2000 by ASME
View article in PDF format.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In