ZOOMING IN ON THE PROBLEM: JGR engineers used a Nikon AZ100 microscope to capture and analyze images of failed rocker arms. These arms, designed to help the cars accelerate to high speeds without damaging the engine, were experiencing excessive wear and tear even though they were coated with lubricant to prevent just that type of problem. Image: COURTESY OF JOE GIBBS RACING
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Sunday's NASCAR race was bittersweet for Joe Gibbs Racing (JGR). After dominating the early part of the 200-lap Good Sam RV Insurance 500 at Pennsylvania's Pocono Raceway, only one of JGR's drivers—Kyle Busch—managed to finish in the top 10, thanks to a long rain delay and problems in the pits. Yet even more important than Busch's second-place finish (and the 15th- and 26th-place finishes of teammates Denny Hamlin and Joey Logano, respectively) was the absence of engine problems that have plagued JGR all season.
NASCAR racers cover hundreds of kilometers at any given event at speeds at times exceeding 300 kilometers per hour. Tires, suspension and hundreds of other components must work together flawlessly to keep a driver in contention, but without an engine reliably delivering upward of 700 horsepower, that driver will struggle to keep up with the pack. Whereas many problems can be addressed in the pit area during a race, major engine failure—the result of a cracked engine block, broken valve, damaged piston or any of a dozen other causes—is not one of them. Once the race starts a "blown" engine cannot be replaced, although a problematic engine may be replaced prior to a race.
Hamlin, ranked 11th in the NASCAR standings this year going into this weekend's race, has had to swap out engines before two of his past three races, including the Brickyard 400 in late July. JGR, which won more Sprint Cup races last season than any other, has experienced nine engine failures so far this season prior to races. In the past two seasons, bad engines have cost the team five DNFs (did not finish). These problems put the team's engineers on the spot to diagnose the issue and devise a solution.
With the season well past the halfway point, JGR engineers are hoping upgrades in their lab have helped them turn the corner. Foremost among the new equipment is a high-power Nikon AZ100 Multizoom microscope more likely to be used by scientists to examine biological specimens than by mechanics conducting forensic investigations of car engines and other equipment.
Following an engine failure, JGR engineers thoroughly examine the motor's major internal components—this could be a lifter, a piston or any number of small parts. Precise engineering is crucial to performing well in NASCAR races. "This has been a particularly challenging year as no two failures have been related," JGR Quality Control Engineer Richard Miller says.
In 2010 JGR engineers built 322 motors at $80,000 a piece. "Our target is plus or minus two horsepower at 875 horsepower, and last year we hit it every time but twice," says Mark Bringle, JGR technical sponsor manager. "We're getting 875 horsepower out of 358-cubic-inch motors. If you know anything about motors, that's not supposed to happen. There's really, really violent conditions taking place inside these motors so not only do we look at the parts before assembly, we also look at the parts under a microscope after assembly for stress, cracks and things like that."
To provide some context, a 2012 Chevy Corvette with a 6.2-liter V-8 engine delivers about 430 horsepower. Your, ahem, "friend's" Chrysler Town and Country V-6 minivan gets about 280 horsepower, whereas your neighbor's four-cylinder Toyota Prius maxes out at about 135 horsepower.
JGR began using the Nikon microscope early last season to diagnose problems with their engines' rocker arms, which are reciprocating levers that convey radial movement from the camshaft into linear movement. These arms, designed to help the cars accelerate to high speeds without damaging the engine, were experiencing excessive wear and tear even though they were coated with lubricant to prevent just that type of problem.
After being contacted by the racing team, Nikon shipped JGR an AZ100, which combines the wide-field-of-view advantages of a stereoscopic zoom microscope (from 5x to 400x) with those of a metallographic microscope typically used by materials scientists. JGR engineers used the microscope, with its high-resolution lens and the digital imaging system, to capture and analyze images of failed rocker arms. Through video conferencing and image sharing with the manufacturer of the rocker arms, it took the two groups only 90 minutes to determine that "inclusion and discoloration in the coating were responsible for the rocker arms' damage—and that the excessive stress and heat placed on these parts were not being properly deflected," according to Nikon.
Since then, JGR engineers have used the microscope to zoom in on other problem areas in engines, take digital snapshots and send them to parts-makers. Previously, JGR had used a crude microscope that could not take photos, which meant engineers had to describe what they were seeing to engine part–makers. Most car owners, NASCAR or otherwise, can relate to this: "That was the problem. When you're trying to describe something to someone as abnormal, it's very difficult a lot of times to describe," Bringle says.
This season, the AZ100 has been instrumental in helping JGR diagnose issues related to valve-train components, among others. "We were able to very quickly identify an issue with our valve springs and with [the] coating on our valve stems," Miller says. "As you can imagine, the quicker we can identify an issue, the quicker we can implement a corrective action internally and convey our findings to the vendor."
JGR attributes this fast turnaround to helping the team stay in contention this year, despite its engine issues. The team's next shot to test its progress comes at this weekend's race in Watkins Glen, N.Y.
View a slide show of images from JGR's forensic examinations using the Nikon AZ100 (as well as JGR's top race cars).