Thousands of college and university faculty members lost guaranteed labor union collective bargaining rights yesterday when the Supreme Court ruled, 5 to 4, that many of them are part of management, not labor.

The ruling is a blow to relatively recent union organizing efforts on the campuses of private colleges. Public employes, including teachers and professors, never have been protected by federal labor law.

The court held that where faculty members play a major role in governing an institution; they are managerial employes expected to give their "undivided loyalty" to management.Educators play such roles in most major private colleges.

They are thus not protected by the National Labor Relations Act, which guarantees such things as unfettered organizing, union elections and "fair" treatment by employers of a union during collective bargaining.

The case was prompted by Yeshiva University in New York, where the administration refused to negotiate with a faculty union on grounds the professors were part of management.

The National Labor Relations Board agreed with the faculty, but was overruled by the court yesterday.

At Yeshiva, Justice Lewis Powell wrote for the majority, faculty committees "effectively" determine curriculum, grading systems, admissions policies, course schedules and tenure standards.

Although some of the faculty decisions can be vetoed by the school administration, "the controlling consideration . . . is that the faculty of Yeshiva University exercises authority which in any other context unquestionably would be managerial."

In fact, he said, "it is difficult to imagine decisions more managerial than these.

"To the extent the industrial analogy applies, the faculty determines within each school the product to be produced, the terms upon which it will be offered and the customers who will be served."

Powell was joined by Chief Justice Warren Burger and Justice Potter Stewart, William Rehnquist and John Paul Stevens. Justices William Brennan, Byron White, Thurgood Marshall and Harry Blackmun dissented.