Hello, I just bought a 91 prelude and the motor has a really bad tap to it, I can't find it probeing around but by ear it definately sounds like its coming from the head. the valves have jsut been adjusted and trippled checked and the noise didn't change. Someone mentioned to me that it could have a few bent valves. Is this possible? The car drives and acts great it just taps like crazy. It doesn't seem to knock but tap. Theres no metal in the oil and it doesn't change by pulling spark plug wires off. Any help would be greatly appreciated.