Miata Turbo Forum - Boost cars, acquire cats. - Engine/Trans noise woes, rattling/ticking? Stock drivetrain.

So for the past couple months, I've been trying to figure out what this noise is that my car is making. I cant really describe aside from the sound of a bearing with a pit in the race that makes a "tap tap" added in with a rattling washer.

I've tried to eliminate variables, but I just cant figure it out for the life of me.

My car is a 95, all stock drivetrain + K&N drop in filter and a Jackson racing header.

- When the sound happens. -
The sound does not occur until the motor is warm, and it seems like it happens on warmer days.

Sometimes it slightly makes the noise if i let the clutch out at around 1300 rpms. Higher rpms it does not.

In third, fourth, and fifth gear, at or above 3.5k RPMs. But not first or second.

If I climb a big hill on the freeway, it will make the noise throughout the whole pull.

- What I've tried. -

My first thought was speedo cable, I threw a new one on and it seemed to fix the problem. Until the weather got hot again.

I've removed my A/C belt and tensioner(car has no P/S) thinking it was the A/C clutch. No dice.

I've looked for any type of loose bolt/washer or the like, but it doesnt sound like its just a loose washer, theres an RPM related "tick" associated with it.

Someone mentioned clutch pilot bearing, or TOB, but I've never had one go bad so I dont know what that feels like.

You can hear the sound in this video as my car drives by. I cannot replicate the sound unless the car is under load, it does not make the sound while revving in neutral.

http://youtu.be/nJuuRlX4hSY

Is my motor gonna asplode?