Former Arlington legislator Ira Lechner, buoyed by a sweep of Northern Virginia's Democratic delegate-selection meetings, yesterday upstaged the party's front-running candidate for lieutenant governor Richard (Dick) Davis.

Lechner's surprising showing seemed certain to force Davis, an ally of gubernatorial candidate Charles S. Robb of McLean, into a convention floor fight over the party's No. 2 slot on the November ballot.

Unofficial returns compiled by the Associated Press showed Lechner, a Washington labor lawyer and a liberal maverick by Virginia standards, had a lead of 177 delegates over Davis, a selfmade millionaire and a former Democratic Party chairman. The AP said Lechner had won 1,028 delegates to a state nominating convention to Davis's 851.

A top strategist to Davis, a close ally of Lt. Gov. Robb and long considered a front-runner in his race, earlier had predicted that Davis would lead Lechner by 20 delegates when all the Norther Virginia results were known.

Richmond legislator Gerald Baliles, a former assistant state attorney general, was reported to be leading populist Del. Erwin S. (Shad) Solomon of Bath County by a margin of 633 delegates to 559 in the race for the nomination for the state's top legal office. The AP reported that 568 delegates elected yesterday were listed as uncommitted in that race.

Neither Lechner nor Baliles seemed likely to have won enough delegates at 68 mass meetings around the state yesterday to grab a first-ballot victory at the party's state convention at Virginia Beach next month. More delegates were to be selected at meetings Monday night, but probably not enough give either man victory.

"It will be a very close vote, but I believe we will be ahead," said Davis campaign manager Bobby Watson.

Lechner last night predicted that the would emerge the front-runner when votes from yesterday's meetings and those planned for Monday night are counted. Lechner, who has claimed that his campaign seeks to purge Virginia's Democratic party of the last vestiges of the once dominant Byrd machine, said he was optimistic that he would win the nomination for the state's second highest office, a race he lost four years ago to Robb.

But some Democratic Party officials were fearful that a Lechner nomination would alienate the conservatives that Davis and Robb have been seeking to attract. "If Lechner sneaks by us, the real loser will be Chuck Robb because there's no question they're not compatible," Watson said yesterday.

The Democrats will face a Republican ticket to be headed by State Attorney General J. Marshall Coleman, a lieutenant governor nominee to be picked at party convention in June, and former Fairfax legislator Wyatt Durrette, who is unopposed for the GOP nomination for attorney general.

Virginia Republicans had been hoping for a strong showing by Lechner, fearing Davis as a conservative and politically savvy politician who would be a formidable opponent who could draw campaign funds for the party this fall. Lechner draws much of his support from labor unions and teachers -- groups who have supported Democrats in the past in Virginia -- but whose support has not been enough to propel many to victory in statewide elections.

While officials at the Davis headquarters yesterday were predicting a narrow victory, Lechner supporters were confident that populous Northern Virginia would give their condidate an edge. Returns from Fairfax County, for example, gave Lechner 220 delegates to six for Davis and Lechner scored a clean sweep in Prince William County, winning all 76 of its delegates.

"People out here for Lechner are not just pie-in-the-sky, last-stand liberals," said Jim Schroll, a Lechner campaign worker and candidate for one of the 114 delegate positions in Arlington.

The race between Davis and Lechner developed into an acrimonious and bitter debate over the past week, as supporters of the two men men charged each other with offenses ranging from vote fraud to felonious assult. The results yesterday did not seem to resolve that dispute, raising the possibility that Robb, who has remained impartial throughout the campaign, might be faced with the difficult decision of whom to support.

The turnout of labor groups yesterday for Lechner, including the American Federation of State and County Municipal Employees (AFSCME), irritated some of Davis' supporters.

"At 12 noon they marched all these AFSCME people in here who we'd never seen before," said Jared Cameron, the Alexandria campaign corrdinator for Davis, nodding at an AFSCME table set up in the lobby of Minnie Howard School.

The race for the attorney general nomination has been marked by what campaign officials were referring to as the "Lechner effect." In Northern Virginia, for instance, Solomon had more delegates pledged to him than Baliles had fielded. But there were more uncommitted delegates filed than those committed for either Solomon or Baliles. Those delegates belong to Lechner, who reportedly intends to use them as bargaining chips before the state convention.

"When you get around to power politics, I don't know which way it will go," says Solomon.

Saolomon said last week he would prefer a primary to a convention. Other Democrats agree, including some blacks and party activists who complaigned to the Justice Department earlier this year that conventions dilute the voting strength of black Democrats.

But Friday the Justice Department sent a letter to party leaders approving the delegate selection process and convention plans.

That decision, and the arguments that led up to it, were a main topic of conversation yesterday at mass meetings in Northern Virginia. Fred Berghoefer, the Arlington Democratic chairman, said he liked primaries because they generated more publicity for Democratic candidates.

Del. Mary Marshall of Arlington, however, said primaries were too expensive and often led to excessive blood letting. "I am aware, though, that conventions can be more easily dominated by a small group than primaries," said Marshall.

Another objection to the convention was based on the confusion that resulted from trying to elect delegates for three separate candidates. In Alexandria, for example, voters were handed a ballot with 171 names and told to choose 72 delegates.

"I would describe it as a real zoo," said Pam Miles, a Northen Virginia campaign manager for Baliles.

"This form of choosing rather than a primary tends to be divisive," said Bill Romjue, the state coordinator for Solomon. "It lends itself to suspicion that deals are going to be made."

But for Democrats who like to play the political game, the mass meetings and convention were an opportunity for pleasure. "I think it's splendidly confusing," said Del. Elise Heinz of Arlington.