American officials pledged yesterday that the Middle East summit conference at Camp David this week will not result in a rewritten version of United Nations Resolution 242, the ambiguously worded document around which Middle East peace efforts have been built for 11 years.

The officials, who insisted on anonymity, told reporters at a presummit briefing that the talks beginning Tuesday night or Wednesday will focus on a narrowing of the "differences in interpretation" of the resolution.

Stressing the unpredictability of the discussions, they said the United States hopes the summit will produce a fresh set of instructions to Egyptian and Israeli negotiators based on a narrowing of differences at the summit.

It was clear, from the officials' comments, that the American strategy going into the summit is to lower expectations of the outcome so that anything short of a total breakdown might be judged at least a partial success, keeping the hope of an ultimate settlement alive.

"We do not expect to try to negotiate all of the points of a peace treaty" but to discuss "principles and a framework" for further talks, one official said.

"You really have to approach this in a totally open way," another official added. "It is unprecedented and what will come up we simply don't know."

U.N. Resolution 242, adopted after the 1967 Arab-Israeli War, was a compromise acceptable to all sides because it left room for varying interpretations.

The resolution calls for Israeli withdrawal from territories occupied during the war, leaving the Arabs free to claim that it means all of the Sinai Peninsula Golan Heights, the West Bank of the Jordan River and the Gazz Strip, and the Israelis to claim that it means only that they have to return some of the occupied territories.

The U.S. officials yesterday stead-fastly refused to restate the American position on this key point of difference, saying it is well known. President Carter has said he favors Israeli withdrawal from the occupied territories with some unspecified "minor" border adjustments.

The Egyptians consider this formula much closer to their position than to Israel's and are going to Camp David with the hope that the president is determined to advance some variation of it as the basis for continued talks.

The American officials, however, stressed that there will be no effort to tamper with the language of Resolution 242. Israel has long been concerned that efforts to rewrite the document might lead to a more specific definition of the term withdrawal.

Calling the resolution "sacred," one official said yesterday, "Nobody wants to change it. It is there and we do not wish to touch it."

The president will leave for Camp David, the isolated presidential retreat in Maryland's Catoctin Mountains, [WORDS ILLEGIBLE] giving him almost a full day there before the talks begin. Egyptian President Anwar Sadat is expected to arrive at Camp David Tuesday afternoon and Israeli Prime Minister Menachen Begin shortly thereafter.

It remained unclear yesterday just how the talks will proceed. The American officials said they hoped the open-ended nature of the discussions - there is no set concluding time or other deadlines for the talks that could last a week or more - and the informality of the setting will produce "full discussions" of the complex issues.

They said the president first wants to hear out the two sides on their views of the issues in what could be separate talks with Sadat and Begin before the three leaders thrash opt the differences. Carter, the officials said, "will put forward his own suggestions when he thinks it would be useful."

The three main issues, as long defined by the Carter Administration, are recognition of Israel as a legitimate entity in the Middle East, Israeli withdrawal from the occupied territories and accompanying guarantees of Israel's security, and a solution to the Palestinian problem.

What "suggestions" Carter will advance at the summit remained unclear, but the U.S. officials, in keeping with the administration's longstanding insistence that there is no "American plan" for a peace settlement, continued to downplay published suggestions that the president may explore the possiblity of an American guarantee of Israel's security.

"If they (Sadat and Begin) think it would be helpful to discuss guarantees by outside parties, the U.S. would consider that," one official said.

One thing that is certain about the summit is that it will be accompanied by an almost total news blackout. Whit House press secretary Jody Powell and his Egyptian and Israeli counterparts have agreed that Powell will conduct "minimal" daily briefings for reporters and that none of the ground sessions for the news delegations.

Secretary of State Cyrus R. Vance is expected to accompany Sadat and copter flights from Andrews Air participate in the Camp David. Vance will and may hold separate discussions with the Egyptian and Israeli foreign ministers.

The American party for the summit will also include national security affairs adviser Zbigniew Brzezinski, William Quandt of the National Security Council staff, special presidential envoy Alfred L. Atherton Jr., Assistant Secretary of State Harold H. Saunders, Hermann F. Eilts, the U.S. ambassador to Egypt, and Samuel Lewis, the U.S. ambassador to Israel.

Vice President Mondale and White House political adviser Hamilton Jordan may attend some of the discussions and Defense Secretary Harold Brown wll the available if needed, officials said.