The western portion of the Stanley Cup playoffs, reduced to secondary status by the early departure of the Edmonton Oilers and Minnesota North Stars, occupies center stage Thursday night.

While the champion New York Islanders await the result, the Vancouver Canucks and Chicago Black Hawks will resume the Campbell Conference series here. Vancouver, after winning, 5-3, Tuesday, needs only one more victory to create the first coast-to-coast final in Stanley Cup history.

The Hawks not only face the unenviable task of trying to erase a 3-1 deficit in the best-of-seven series, but they undertake it without captain Terry Ruskowski, who has reinjured a separated shoulder.

Chicago has been bedeviled by penalties even more than by towel-waving Vancouver fans while losing the last two games. On Tuesday, the Canucks built a 3-0 lead by scoring on an ordinary power play, a two-man advantage and a delayed penalty.

At least the Hawks need not worry about the distraction of the towels on Thursday. The foolishness began here a week ago, during Chicago's only victory, when Vancouver Coach Roger Neilson and two players, Tiger Williams and Gerry Minor, put towels on the blades of their sticks and waved them at referee Bob Myers.

All three were ejected and the Canucks later were fined $10,000 and Neilson $1,000 by the NHL. Vancouver fans, however, turned the incident to the Canucks' advantage by bringing towels to Pacific Coliseum and taunting the Hawks.

The Canucks have lost only two of their last 21 games in a remarkable stretch that began in modest fashion with a 6-6 tie in Washington March 17. Most NHL folks are hoping that they can give the Islanders a better battle than the Quebec Nordiques, who fizzled in four straight games.

Quebec trailed, 3-0, after 56 minutes in Tuesday's windup in Quebec City, scored two goals in 37 seconds and was unable to launch a shot the rest of the way as an empty-netter completed the Islanders' 4-2 triumph.

Although both the Canucks and Hawks were sub-.500 teams during the regular season, the Islanders do not consider the final to be a walkover or an anticlimax.

"That doesn't make it any less," said Bryan Trottier, leading scorer of the playoffs with 22 points. "The final is always very exciting and it doesn't matter who you're against. I can't explain it. It's just a special feeling to get to the finals--and, of course, when you win it."