United States Olympic Committee President Robert Helmick and newly named executive director Baaron Pittenger said yesterday they did not expect recent upheavals in the organization to disrupt the Olympic effort this year, but added that they are considering some long-range restructuring to make the largely volunteer body more effective.

The USOC named Pittenger executive director last week after Harvey Schiller suddenly resigned only 18 days into his tenure and returned to his former job as commissioner of the Southeastern Conference. Schiller cited the administrative difficulty of the executive director's job and also a desire to do more effective USOC volunteer work.

Schiller was the second executive director to resign suddenly in the last six months. In August, Gen. George Miller quit amid reports that he and Helmick, who as president is a volunteer, had trouble communicating. It was initially thought that Schiller's resignation would represent at the least a public-relations problem for the USOC, particularly with the Winter Olympics in Calgary set to open Feb. 13.

But Helmick said he saw no indication of dissatisfaction from any of the national sports governing bodies or corporate sponsors. He said Pittenger, an 11-year veteran of USOC administration, would keep continuity in both the bureaucracy and all important fund raising areas.

"We have not received one letter on this issue or any expression of concern from sponsors," he said. "I can't get into the minds of people, but I see no evidence of concern. I think this demonstrated our strength, rather than our weakness. No events have been jarred by this."

Helmick and Pittenger held a telephone news conference yesterday from Des Moines, Iowa, to discuss the resignation of Schiller, which became formal on Tuesday. Helmick had lobbied one last time over the weekend in an attempt to keep Schiller, and enlisted New York Yankees owner George Steinbrenner, an influential USOC volunteer.

Though Schiller's resignation won't affect Olympic preparations, it did raise questions about the management structure and effectiveness of the USOC. The U.S. teams are not expected to be particularly competitive in Calgary, and though Helmick said that isn't necessarily tied to the USOC administrative problems, unspecified improvements in the organization are being contemplated.

One of Schiller's reasons for quitting was that he foresaw myriad difficulties in getting anything accomplished through the current bureaucracy. The USOC is primarily a voluntary organization, with volunteers frequently dictating policy, while USOC employees take on the difficult job of implementing the paper work and dealing with the many diverse and sometimes authoritative governing bodies in each sport.

Helmick said Schiller is welcome to remain a USOC volunteer, but no specific role has been set for him. Previously, Schiller served as chairman of games preparation.

Restructuring could be justified on the simple basis that the Olympic effort has grown tremendously. In 1956, the Olympic budget was just $2.3 million; it now is well over $100 million. As an influential volunteer and representative of the public interest, Steinbrenner said some alterations could make the USOC more efficient.

"It's getting so big, maybe it's got to make some changes to function better," he said.

Helmick said a report on the issue will be submitted at the next USOC executive board meeting in April.

In the meantime Pittenger, who has served the USOC in various capacities for over a decade, represents both stability and an opportunity to consolidate. He has a solid working knowledge of the national governing bodies, and showed ability to be effective by organizing what became the Olympic Sports Festival. Pittenger said he intends to attempt to improve things before the 1992 Olympics.

"Frankly," he said, "we need to figure out how to be more effective in the next quadrennial."