THE CLOCK HIGH ON THE WALL of the principal’s office at Intermediate School 61 is stuck at 4:18, but Sam Penceal doesn’t need the right time. He comes early. He stays late. He’s at his desk on days when there are no classes. That’s right, he’s new. Penceal, 51, is a principal for the first time. He never had an assistant principal’s job, which is the usual way to climb. Now he’s in charge of 1,400 students and 94 teachers at the Crown Heights, Brooklyn, corner of Empire Blvd. and New York Ave. “I was excited about coming here and I’m still excited,” he says. The excitement is starting to spread to the teachers, and maybe that means the kids, seventh, eighth and ninth-graders, are next. Penceal expects to make a difference. But the first night I met him, 30 years ago, he made no difference at all. Syracuse and Princeton were playing a basketball game and the Princeton star, Bill Bradley, scored 36 points. This same Bradley would spend important years with the Knicks and in the U.