Strange Rattle/Chatter Above 1000RPM?

[evan_aggie]

Dxd stg 5 - YouTube (http://www.youtube.com/watch?v=P9IWkhdrjP8)

At 22-23s, 37-38s, 51-53s into the video, you can hear the chatter w/o hearing all of the exhaust.

It is a southbend stage 5 clutch, made of dual feramic discs. I've heard these tend to chatter, but what I hear is weird. Plus, the noise doesn't change with the clutch pedal in/out. It is only dependent on being above 1000rpm.

Any ideas? I know this is a z32 but I was hoping someone else may have an idea.

[evan_aggie]

Anyone? The link is a video of the noise....

[rcdad123]

can you feel it on the clutch pedal? sounds like an exhaust leak to me.

[KiLLeR2001]

How does the car pull when you get on it? If it feels weird like its not applying all the power to the clutch, you may have a loose flywheel.

[evan_aggie]

There was a small exhaust leak, but I fixed that after the video. If you check the time stamp I mention, you'll hear more rattle than anything else.

The car pulls great. The clutch is new and the flywheel is a segmented RPS. Those are both different than my previous setup. So, that could somehow be an issue. However, I also did install a new fork, and the koyo bearing that came with the clutch from South Bend.

[Megaman V2]

Considering you are holding the cam at the side of the Z you assume its comming from the tranny or the exhust? Have you checked to see if the actual sound is comming from the engine itself? kind of sounds like it spun a bearing. and the rod is knocking. IDK about z motor sets but in an SR this type of sound occurs when a bearing is shot. try and un-plug your injectors 1 at a time see if there is a change in idle. if there is no change in one of the cylnders thats a good indacation its a bearing. Hope this helps.

[evan_aggie]

Man, I hope you are wrong about that. =)

Pulling a plug (spark is easier) would rule out faulty spark, faulty injector. How would the bearing being shot show any change in the power balance test. If you are saying it is a failed bearing, then that chattering is the bearing noise, but the piston still travels up for compression right?

Plus, I'm thinking I'd have really low oil pressure.

[Megaman V2]

The bearing failing would cause the rod to jerk up and down on the crank, Wich sounds like what I am hearing. in the case of an SR its hard to pinpoint knocks cause the sound echo's through the aluminum. When diagnosing a knocking sound in an SR I pop the valve cover off and check the lifters, and the timing chain guide. (I just take it out) IDK how the timing chains are on a Z but I would check that too, I also know that cam sprockets tend to cause knocking sounds. does your motor shake at all wail the knocking is happening? like its off balance? and SR's have the coil pack cover thats why I said pull the injector lolz.

[evan_aggie]

no, it's not a spun bearing. it would be much more detrimental. My car seems to be in fine working condition aside from the chatter near the bell housing.