The Baltimore Orioles finished a three-game sweep of California almost effortlessly tonight, drubbing the fallen Angels, 7-1, on Scott McGregor's composed and nearly nonchalent seven-hitter.

The Birds who now trial the Yankees-- 6-4 losers in Seattle -- by 1 1/2 games, have now won five in a row, as well as 16 to 20 in their August of extreme heat. McGregor, whose record is 15-6 in what will probably be the first 20-win season of his career, has given California just three earned runs in his last 43.2 innings against the Angels over two years.

The player who ignited the Birds both in their 10th-inning win here Wednesday (when he walked, stole and scored the winning run) and tonight with a pair of important hits, includinga home run, was tough veteran John Lowenstein.

Earlier this year, Lowenstein went on the disabled list with a serious hip bruise. In his first game back he knocked himself out making a running catch before crashing into the wall and reinjuring his hip in the same spot.

"John, you just came back from running into a wall with your hip," said Jim Palmer. "Why did you do it again?"

"So I could catch the ball," said Lowenstein.

That is a spirit with which the lackadaisical Angels are totally unfamiliar. Tonight, there was only one team in this game -- the Orioles. The Angels folded their tent and quit as soon as Baltimore scored three runs in the fifth for a 3-1 lead which KOedwoeful Angel starter Chris Knapp.

In the Bird locker room, the players were loudly humming the USC Trojan fight song in honor of Rich Dauer, who, the night before, made an ugly mental error, failing to complete a double play when he thought the inning was over and jogging off the field with his head down as no one else moved.

"I never do anything like that," saidthe chargrined Dauer, who went four for four tonight, including the two-run bases-loaded double that proved to be the game-winning hit.

Also in for needling in his spotlight moment was Lowenstein.

"Brother Lo . . . the only man whosehometown is Las Vegas, the city without clocks," intoned Ken Singleton. "The only question about John is whether he ever sleeps."

'It really helps to be an all-around good ballplayer," deadpanned Lowenstein, who terms the eight years of his career before becoming an Oriole as "meaningless."

Thereafter, the Birds could have named their score.

All in all, the Orioles trip to balmy Disneyland has been a cushy visit where they won twice with effortless ease, and, in the one game they might have lost, had the game handed to them by the hapless, heartless Angels.

In this baseball land of nod, the loudest cheers in three nights have been for beach balls being batted about the stands during the game.Play was even stopped once when the surf's-up noise became so loud. This is the franchise that has already drawn more than 1.8 million in '80, despite the fact that thousands of fans got up and left Tuesday's game before the eighth inning to beat traffic, despite the fact that Steve Stone had no-hitter going.

Give these fans a baseball primer.

When the Birds have not been accepting Angels favors, they have been thinking about the New York Yankees.

"I was very unimpressed by (Yankee Owner) George Steinbrenner's comments criticizing his players and hismanager," said Mark Belanger. "It shows no confidence in people you've hired to do a job for you."

Orioles who had formerly been Yankees gave mock imitations of Steinbrenner's clubhouse pep talks, including one tape-recorded Steinbrenner win-one-for-the-Gipper lecture that hadthe Yanks in gales of laughter so loud they couldn't hear the last halfof it.

"How can Steinbrenner knock Regie, the guy who's carried his club?" said Steve Stone. "It can only have a bad effect. They were crumbling even before Nettles got sick. They don't need this."

It is hard to pinpoint exactly when a team loses a bit of momentum or confidence and unconsciously revs down. In the Orioles' case, however, just such a slackening of pace followed their dismal performance Wednesday night here, as they squandered a three-run lead in the ninth before winning, 6-5, in the 10th.

It ruffles the Birds to watch themselves make fundamental blunders because their success is predicated on mistake-free baseball. Yet on Wednesday, Rich Dauer lost track of the number of outs and failed to finish a double-play pivot, Earl Weaver left in a struggling starter (Mike Flanagan) too long and the Orioles allowed the potential game-winning run get to second in the ninth with none out because they threw to the wrong base.

All of this mattered naught, however because the Angels play like a rich, pampered, coudn't-care-less team allowing runners to be picked off, failing to execute simple, sacrifice bunts when the game is on the line, and misplaying easy line drives when they mean the game. And that was all on Wednesday alone.

This evening's game should have been a foregone-conclusion Oriole victory.

The dismal Angels, by brutal contrast, are one of the worst and most injured teams in baseball. "If you can't beat this lineup, with the guys they have out and the others playing hurt, then you'll never beat anybody," said Jim Palmer before the game.

In addition, the Angels, whose entire pitching staff is a wreck, started perhaps the worst hurler in any rotationthis side of AAA -- Knapp, who had one victory and a 7.13 ERA in 17 previous starts.

And still, the Angels took a 1-0 lead. Knapp, without a win in two months, gave up rockets in every inning,but escaped.

McGregor was excellent, but gave up a quick run in the fourth when Dan Ford, who was openly accused of malingering earlier this season by teammates, doubled to left on the first pitch of the inning and scored on Don Baylor's RBI single to left.

McGregor, as usual, was his best in mild jams. After a Bobby Grich single in the second, he fanned Bobby Clark and Jason Thompson (when he wears on his watch chain) on six pitches.

It was, of course, only a matter of time before the O's awoke against such humble opposition and began the whomping.

Leading off the fifth, just after California's run, Lowenstein cracked a single past Thompson's lunge. Knapp, who has averaged a measly 4.16 innings per start, ensured another short night's work by walking DeCinces. Belanger then laid down a good, quick sacrifice bunt that third baseman Carney Lansford botched for a bases-loading error.

Although the Angels still led, the Orioles had won. Dauer picked out a letter-high fast bass and doubled to right center for a 2.1 Oriole lead. Al Bumbrey conked the next pitch to left for a sacrifice fly. One walk later, Knapp had been KOed while lowering his ERA.

The rout was on as the Birds scored three more in the seventh. Dauer singled to left and Bumbrey beat out a good bunt hit to third that Lansford bobbled when he might have had a play Rick Dempsey then got his second double of the night, a two-run job, on a hooking liner to left that Don Baylor might have snagged had he not been Don Baylor (it clanked off his glove).

It took considerable ingenuity to getthe gimpy Dempsey home for a 7-1 Bird lead. A single to left by the still slum-ridden Singleton got Dempsey to third and Eddie Murray's long sacrifice fly brought Dempsey galumphing home.