"The Betsy" is a needles solemn but glossly and diverting movie version of a Harold Robbins best seller. Laurence Olivier, colorfully midcast as a foxy grandpa captain of American industry, a visionary auto manufacturer named Loren Hardeman, leads a parade of expert, entertaining or at least photogenic performers through the twists and turns of an Oedipal conflict that threatens the birth of the Betsy, the fuel-efficient family car of the 21st century.

The film falls considerably short of the irresistible, rousing kitsch standards set by King Vidor in "The Fountainhead" and Edward Dmytryk in "The Carpetbaggers." Ultimately, it's not even as risible as "The Other Side of Midnight," although it's directed in a similar bewildering manner: slow and dignified instead of brisk and gaudy.

Maybe the Emmys he won for both chapters of "Eleanor and Franklin" left director Daniel Petrie in an inappropriate frame of mind for "The Betsy," which would appear to call for a certain zestful vulgarity. Nothing crude. The ripping Lesley-Anne Down has the right idea, and she is certainly going to give millions of moviegoers ideas, including a growing desire to see her emerge as one of the stars of the '80s. Her classy but carnal Lady Roberta Ayres, a titled interior decorator, is the most amusing and glamorous tantilizer to shimmer across the screen in quite some time.

Unfortunately, her character is always on the periphery of the plot, which finds her provider, Robert Duval as Loren Hardeman III, trying to sabotage his grandfather's dream car - which is named after his own daughter, Kathleen Beller, who falls in love with ambitious young diamond-in-the-rough designer Tommy Lee Jones, who also is involved with Lady Bobby.

The movie might have been slightly sensational if Down had been at the center of the action. The humorous sensuality she brings to this assignment should have characterized the whole project. Petrie tries to keep it dignified even when Down and Jones disrobe for some soft-core dalliance.

The most impressive aspect of Jones' performance is his facade of self-control when being subjected to Down's withering battery of beckoning smiles. He appears to carry playing it cool beyond the call of duty. Perhaps this reserve is meant to explain his lack of romantic soul The hero is required to prefer the doe-eyed, heavy-breasted ingenue and her multi-million-dollar inheritance, a preference that makes him look fundamentally sleazy and opportunistic.

In fact, he calls for Mafia assistance when the chips are down, a twist that Robbins or the screenwriters really should have straightened out.It's not necessary to achieve his aims - and it ends the story on a sour note, with both Jones and Olivier lookin glike rather deranged wheeler-dealers. Audiences may be amused playing place-the-accent with Olivier, who evidently affect's a Midwestern wang but occasionally wanders off to Texas or Ireland. His jolly old codger number suggests a cross of Joseph Cotton in his white-haired scene in "Citizen Kane" with Walter Huston in "The Treasure of Sierra Madre."

Oliviers skill and authority always are evident, and they're particularly impressive in a sequencel where Hardeman feels compelled to relieve his weaking son, played by Paul Rudd, of corporate command. Nevertheless, it's more than a bit dismaying to see the world's greatest liping actor compromised on several occasions by insurmountably trashy situations or dialogue that just doesn't sing, no matter how much he tries to orchestrate the lines with surprising inflections or beats or emphasis. It is simply wasteful to turn such a performer loose on a soliloquy like the following: "I made it for you, son. I made it all for you. He doesn't know, does he? He doesn't understand, does he? It's not the money, it's the car."

It can be depressing to hear such drab lines spoken by a superlative actor. This might have been a challenge for someone like Katherine Ross, who plays Rudd's estranged wife. For Olivier it's pittance, and ultimatelyan insult to both the performer and the audience.