Chief mechanic Louie Unser dies.

Louie Unser, who was chief mechanic on two of his brothers' cars when they made their debuts in the Indianapolis 500, has died at the age of 71.

Unser was the twin brother of Jerry Unser who, in 1958, became the first family member to qualify for the 500. Louie was his chief mechanic on that occasion and, in 1965, handled the same duties for youngest brother Al, who went on to the win the race four times. Bobby, the other Unser brother, won the Indianapolis 500 three times, but Jerry was fatally injured in a 1959 accident at the Speedway.

"If it wasn't for Louie, I wouldn't have made it at the Speedway," Al said, "He pushed me."

Louie was born ten minutes after Jerry on 15 November 1932, in Colorado Springs, and moved with the family to Albuquerque when he was four. However, in 1955, Jerry Unser Sr took his sons back to Colorado for the annual Pikes Peak Hill Climb, and it was there that the boys' interest really took off.

Louie was driving a tour bus up the mountain, but his father refused to allow him to race in the wheel tracks of his famous uncle of the same name. So Louie slipped into brother Bobby's Jaguar on race day and placed third overall.

But Louie had greater skills as a mechanic and, in 1956, went to work for Bill Stroppe's factory team that was based next door to brother's Jerry's DePaolo Engineering USAC racing team. Both teams folded in 1957 when factories withdrew their support, but the brothers purchased the equipment and went racing together.

Jerry earned the 1957 stock car championship and presented his diamond ring to Louie, who wore it the rest of his life. Louie also was named mechanic of the year that season.

Jerry and Louie showed up at Indy in 1958, and Jerry jumped from car to car until he qualified the McKay Special in 24th place. However, he didn't get to complete a lap as he got tangled up in an accident in the north chute on turn one.

From 1960-62, Louie worked with Stroppe, Carroll Shelby's AC Cobra team and others building engines in the shop, and changing tires and refuelling cars in the races. He also worked on a car in the four-month East Africa Safari in 1964, despite suffering from multiple sclerosis.

He still managed the strength to act as crew chief with Al at Indy in 1965, before retiring from trackside involvement. He started an engine-building business in southern California, and his powerplants helped brother Bobby and Mario Andretti to race to victories at Pikes Peak. He also built strong, winning engines for sprint cars, sports cars and racing boats.

By the 1970s, Louie was confined to a wheelchair, but he continued working until the 1990s. He and his wife, Laverne, participated in many MS-related fund-raising and research events over the years, and he was inducted into the Orange County Hall of Fame in 1997. His final visit to the Indianapolis was for the 1999 Brickyard 400.