I've got a B16a that's starting to make a little noise when I start it. I doesn't do it every time though. When I turn the key, sometimes before the engine fires up, it will make a little grinding noise. Kinda like the noise you hear when you try to start a car that's already running (c'mon, you know that sound!).

Could the flywheel be missing a few teeth? I think if the starter was worn or missing teeth, I'd hear the noise every time. I haven't taken the starter out for inspection yet.