The morning of a scheduled interview with Roger Penske turned up cold and rainy at Indianapolis Motor Speedway. The reporter arrived early, uncertain whether inclement weather might have altered Penske’s plans.

But the garage door had been rolled up about two feet. The reporter bent at the waist to peak under the door, saw six pairs of legs up to midcalf and relaxed.

Penske, “The Captain,” was there. That was evident from the trousers with the razor-sharp crease and the dress shoes that would have looked spit-shined if he had just traipsed through mud.

At the appointed hour, 30 seconds either way, the side door opened and the most successful team owner in IndyCar racing history summoned the reporter.

Roger Penske, 75-year-old self-made billionaire and still the heart and soul of an international automotive empire, is no less goal-oriented or attentive to detail and obligation today than he was those 20 some years ago.

His legend and world-wide brand as not only an historic figure in auto racing but also a business mogul continue to grow.

His drivers have won 15 Indianapolis 500s and 12 IndyCar series championships. Penske created the blueprint. He still talks about “human capital” and preaches that effort equals results. The results have been sensational. With one glaring void.

Penske has not achieved a NASCAR Sprint Cup championship, in spite of 76 race victories scattered over 1,571 starts dating back to 1972 but almost entirely since 1990.

Brad Keselowski, an ascendant talent and personality in the sport, could erase that omission from Penske’s résumé Sunday in the season-ending Ford EcoBoost 400 at Homestead-Miami Speedway.

A 15th-place finish or better will enable Keselowski to outpoint remaining challenger Jimmie Johnson, a five-time champion.

Grinning, Penske quipped, “I kid these guys that I don’t want to sit down on the front row [at the Sprint Cup championship banquet] anymore. I want to be up on the stage [as champion team owner] so I can see who’s at the party.”

Rusty Wallace, who drove to 38 of his 55 career victories in the Penske Racing No. 2 Miller Lite livery that Keselowski now steers, will be trackside for ESPN’s telecast Sunday.

He’s part of the media now. Theoretically, he’s supposed to bring a neutral viewpoint to the analysis. But he’s not trying to fool anybody.

“I drove that ‘2’ car forever,” Wallace said, “and I’m really pulling for it.’’

He’s high on Keselowski, but it’s Penske he wants to see celebrating. “Roger has paid his dues. It’s time for him.’’ The Hall of Fame driver is certain that mind-set permeates the garage area.

Wallace, the 1989 Cup champion for Raymond Beadle’s Blue Max team, came closest to giving Penske a championship in 1993. He won 10 races that year, but Dale Earnhardt narrowly outpointed him for one of a record-sharing seven titles. It still eats at him that he couldn’t be the one who put Penske at the head table.

“Roger Penske has taught me so much about life,” Wallace said. “He helped me get into the car business. He has been a mentor. He’s one of my best friends. ... That man has so much integrity.”

Just as Penske is the IndyCar owner against whom all others are measured — and found lacking — Rick Hendrick holds that distinction in Sprint Cup.