A motor oil that shall go unnamed pays Al Unser big bucks to carry its name on his race car in the Indianapolis 500.As part of the deal, the three-time Indy winner was on TV yesterday suggesting that his favorite oil will make the family flivver a champion, too. Left unanswered was the question of why you would drive to the grocery store at 195 miles per hour, but, hey, if America believes toothpaste makes you sexy and panty hose in eggs make you a dancer, some of us will drink the 30-weight oil if Al Unser says it is yummy.

In a carefully orchestrated strategy, the Unser TV commercial played during a nationally televised baseball game on a network other than the network that later in the day was to carry live coverage of the first-day qualifications for the Indianapolis 500.

A month ago, the motor oil's advertising people must have been ready to dive out of their MadAve skyscraper offices into a half-quart of the stuff. At that point. Al Unser was not going to drive in the world's most famous car race. Here he was on TV as the famous Indy Winner. Yet on Indy day. Unser had planned to be racing in Atlanta, or outside Detroit, or, forgive him Mauri Rose in unmentionable Trenton. Somewhere Al Unser could drive in competition with the only car race most people ever heard of.

Had Spectacular Bid run at [WORD ILLEGIBLE] Downs on Kentucky Derby day, white-coated men with butterfly nets would have chased [WORD ILLEGIBLE] and Delp for days. Unser's plan to boycott Indianapolis was of a piece with such kookiness. But perhaps under threat of losing money from sponsors, including the motor oil, who use Indy as a moving billboard Unser yesterday was ready to quantity for the May 27 race.

All this is part of sport's latest alphabet war, CART against USAC.

At the moment, a truce prevails. A month ago four Indy winners - Al Unser, his brother Bobby and Johnny Rutherford (two victories apiece) and Gordon Johncock (one) - were determined to race elsewhere on Indy day. Along with such top runners as Danny Ongals, Rick Mears and Tom Sneva, they are rebels in CART jousting with the Establishment's rulers, the USAC brass.

CART is Championship Auto Racing Teams; USAC is the United States Auto Club. Formed by prominent car owner-builders Roger Penske. Dan Gurney, Tyler Alexander, Jim Hall, Bob Fletcher and Pat Patrick, CART rebelled against what it described as USAC's inability to make Indy-car racing economically feasible.

The costs are astronomical. And Indy car goes for $135,000. A season's campaign may cost $1 million. Jim Hall, who is Al Unser's boss, said his team last year won more money than any racing team ever - a half-million dollars with victories not only at Indy but in USAC's two other 500 mile races at Pocono and Ontario - and yet the operation lost money.

What particularly disturbs the CART people is Indianapolis' division of its proceeds. In a month of qualifying practicing and race day, maybe as many as 750,000 customers will pay their way into the Indianapolis Motor Speedway. Estimates of the gate run as high as $20 million; a conservative guess is that the Speedway takes in $14 million in May as much as $10 million of that coming on race day when an estimated 400,000 fans pay up to $55 a ticket.

Of that $14 million - or $20 million - the drivers who creates what the Speedway advertises as the "Greatest Spectacle in Racing" are paid a [WORD ILLEGIBLE] pittance. The Speedway's contribution to the purse is $873.250 - barely 5 percent of a conservative guess at one month's income. Most galling to CARt is that five years ago the Speedway paid more in prize money, $877,500.

When USAC showed no interest in generosity or in giving the car owners more of a voice in scheduling and car specifications, CART broke away.

CART has run races under its banner and plans more in competition with USAC. It takes small imagination to see such a war bringing down both sides. Except for Indianapolis, the Indy-car circuit has been pitifully weak financially and artistically, for a decade. The circuit can not survive with its money and power divided.

USAC, if outnumbered by CART's big names yet carries a tire iron because four-time Indy winner A. J. Foyt, the sport's biggest drawing card, returned to the fold after a brief alliance with CART. Some Carters believe Foyt was promised special treatment by USAC - perhaps even a step upward toward ownership of the Indianapolis Motor Speedway - but Foyt insists he jilted CART because its leaders "are on an ego trip and want to conquer the racing world."

With Foyt and the Indy 500 USAC needs little else.

So two weeks ago, USAC rejected the entries of six CART car owners and in the process, left all those bigname drivers without wheels.

But last week a judge ruled in CART's favor, saying USAC's rejection of the entries was inordinate punishment for what USAC saw as action detrimental to racing.

Thus the current truce. All the big names will be at this Indy 500. No advertising executives will leap from tall buildings.

"But it's going to get worse before it gets better," said a man on USAC's side. "The whole thing is a charade, anyway Roger Penske started it as a cover. He wants to buy the Speedway for himself. He figures if he has all the top drivers and cars in CART, he'll be the biggest man in racing. Then the Speedway will have to come to him.

The week after Indy, the truce ends. USAC runs the Indy-car at Milwaukee. CART goes to Scranton. Both races will be nationally televised.