A stormy weekend session of the Polish Communist Party's policymaking Central Committee ended today with a decision to move cautiously toward major political and economic reforms while expelling seven of its former leaders as scapegoats for the country's deep crisis.

Reformist members of the 143-member committee launched a determined offensive at the extended two-day plenum. But they were unable to push through radical demand for immediate change and the wholesale condemnation of the former Polish government led by Edward Gierek.

Instead, the Central Committee passed a compromise resolution expelling seven of its members, including former Premier Edward Babiuch, after accusing them of gross errors of judgement. The resolution also called for economic reforms designed to improve the lot of the Polish consumer, greater party democracy and an intensified drive against corruption.

Although Gierek was sharply criticized during the debate, no action was taken against him. The session avoided this delicate subject by deciding that his personal responsibility for the crisis would be discussed at a later date when his health had improved.

Gierek suffered a heart attack shortly before his removal from the leadership a month ago.

The final outcome of the long-awaited meeting thus fell short of the hopes vested in it by the now resurgent reformist wing of the party, which had advocated the need for a clean and rapid break with the past. No new members were elected to the ruling Politiburo, and the purge of hardline politicians was not as spectacular as some had wished.

At a press conference, however, the new head of the Central Committee's information department, Jozef Klasa, said the process of apportioning blame for past errors only had begun. He hinted that there would be more dismissals in the future and particularly at a forthcoming extraordinary party congress.

Klasa refused to set a precise date for the congress, saying full preparations are necessary and at least two more sessions of the Central Committee would have to be held first. This, too, will disappoint the party's reformist wing. It wanted a congress within the next few weeks, partly to enable fresh elections to the Central Committee.

But the Central Committee formally approved a report delivered by the new party leader, Stanislaw Kania, who attempted to strike a careful balance between calls for reform and insistence that there would be no fundamental change in the structure of the one-party state. One reason for Kania's caution, despite the fact that he personally is understood to be convinced of the need for change, is that the composition of the present Central Committee is still tilted against the reformers.

But if the reformers did not get all they wanted, events nevertheless seemed to be moving in their direction. Their sharp criticisms of the old guard have been published in the press and they can count on the support of the party rank and file, which has become increasingly restless over the last two months.

The officials dismissed from the Central Committee included some of Gierek's most powerful lieutenants. Among them was Jerzy Lukaszewicz, formerly in charge of press and ideology, whose self-criticism at the plenum did not save him from being formally held responsible for "shaping a propaganda line divorced from reality."

As well as Babiuch, who was accused of "permitting distortions in party life," others dismissed included Jan Szydlak, the former trade union boss, for "errors in economic policy," and Tadeusz Wrzaszczyk, the former planning chief, for "errors in planning."

Tadeusz Pyka, a former deputy prime minister, was censured for "an irresponsible attitude during the first phase of talks with the Gdansk strike committee," when he represented the government side.

In an even deeper category of disgrace is the former television chief, Maciej Szczepanski, already under criminal investigation for corruption. Expelling him from the Central Committee, the plenum also called on his local party branch to sanction him- the first step toward stripping him of party membership altogether.

At the press conference, Klasa confirmed that the explusion votes had not been unanimous. "Some people withdrew their votes, but it was six o'clock in the morning, so I could not be sure how many there were," he said.

The drive to disgrace the former leaders was spearheaded by Tadeusz Grabski, a deputy prime minister who was himself removed from the Central Committee a year ago after criticizing Gierek's leadership in an outspoken speech. He was brought back from obscurity at the end of August and is becoming increasingly influential.

In a scathing attack, Grabski accused his opponents of "outrageous hypocrisy" in advocating reforms that they had done nothing to promote during their years in power. Accusing them of personal responsibility for the crisis, he said: "They compromised the party in the eyes of the nation and the world. They are people we once trusted, but of whom we now feel ashamed." t

Another prominent politician from the past to speak in favor of a purge was Mieczyslaw Moczar, the controversial former security chief who accumulated great power in the 1960s, but was eased out of the Politburo by Gierek. He attacked what he called "two-faced politicians who would kill their best friend in order to protect their own position."

Moczar, 67, has been using the corruption issue and what was until recently the largely sinecure post of chairman of the Supreme Control Commission to strengthen his influence. He called for the revitalation of the party by clearing it of corruption, servility and flattery.

The increasing importance of Moczar, who led an "anti-Zionist campaign" in 1967 and 1968, was confirmed at the press conference that followed the plenum. Klasa, who was himself one of Moczar's proteges during the late 1960s, described him as "a party insitution" because of his membership of the Central Committee since World War II.