This is real elementary stuff and you probably know it already. I sure don't mean to insult you, but make certain that your rings are properly "clocked" (the gaps are properly spaced around the piston and not neatly lined up in a row), and the oil ring spacer gap should be lined up with the piston pin toward the rear of the engine.

Also, make sure your oil rings are installed correctly with the spacer stopper pins facing in.

Take it from somebody who has done it wrong despite having a piece of paper from the navy saying that he is an engine mechanic.

Jim