Judge Albert T. Blackwell Jr., who heard oral arguments yesterday in the civil suit filed by Arnold Heft against Capital Centre general partner Abe Pollin, said he will make his decision on the suit "hopefully within the next 30 days."

Attorneys for Heft and Pollin said they expect to receive the decision in writing, perhaps in as soon as three weeks. Blackwell gave Pollin's attorneys 10 days to reply to a legal memo filed yesterday by Stephen Grafman, one of Heft's attorneys, leading both sides to believe the judge's opinion will come sometime after that deadline.

Neither Pollin nor Heft, partners in Capital Centre but month-long opponents in Prince George's Circuit Court, would comment on the case.

In oral arguments that typified the often acrimonious trial, Grafman reiterated charges that Pollin, through several June 1982 adjustments in license agreements between the arena and the Washington Bullets and Capitals, secretly and improperly diverted more than $860,000 from Capital Centre to the then financially struggling teams, which Pollin also owns.

He also argued that Pollin, as general partner of the arena, had a duty to inform Heft, a limited partner, of the changes, and that Pollin violated advisory clauses in two written agreements.

"Disclose what you're doing, don't disguise what you're doing," Grafman said of Pollin. "They're partners, for better or worse. At the bare minimum, why didn't Mr. Pollin say, 'Arnold, what do you think about this? We're going to do this.' "

Heft's attorneys asked that Blackwell rule that the adjustments be rescinded and an accounting of their effects be made. There will be no punitive damages.

But John Miles, arguing Pollin's case, charged that Heft's motives for filing the suit were two-fold: "personal recognition and greed.

"As a result of the litigation, he's already achieved the first," Miles said. "It's up to the court to determine if his appetite for the second is satisfied."

Burton Schwalb, another attorney for Pollin, argued that his client acted "fairly and reasonably" in making the changes in his three "business entities:" Capital Centre, the Bullets and the Capitals. He and Miles said the license practices regarding complimentary tickets and box-office and Telscreen fees needed to be adjusted because they had unfairly favored the arena at the expense of the teams.

And they vigorously defended Pollin in the face of the suit's allegation that he acted "willfully and maliciously," maintaining that Pollin's business decisions were "sensible and fair."

Both sides said it is doubtful Blackwell will rule completely for either one. They also indicated it is likely Blackwell's word will not be the final one in what Grafman called "the rather lengthy trial we've all been inflicted with for the last month or so."

If Pollin loses, he almost assuredly would take the case to the Maryland Court of Special Appeals in Annapolis. It's probable that Heft also would appeal if he loses.