Since I reinstalled the gearbox, there are some strange noises heard after start up. When driving or at stand still with my foot off the clutch, there is a slight knocking sound but when the clutch pedal is depressed, a fine whining sound is heard. Do you think its the clutch release bearing or the pressure plate. I'm pretty sure it is not in the box.

could possibly be the throw out bearing did you replace it? also a bolt will do this if its broken or coming out I had it happen on my 240sx and my friends it will only make a knocking noise and you can feel it in the clutch pedal when its in neutral and you can hear it at high rpms

mine has been making the same noise, without the whining sound. It got worse when I changed out the master cylinder, but quieted somewhat after bleeding the system a couple times. my best guess is the same as destroy's. I'll be buying a new clutch soon, and I plan on changing the throwout bearing. I will keep you posted on the noise after the replacement. What bolt are you speaking of, btw?

did not think a broken bolt could cause this. But thanks for the feedback. I intend to change the complete clutch when I install the new engine. Will be using the flywheel from the Z20 (shaved of course) clutch and pressure plate from L28e and new fork and bearing from the 720.

Throw out bearing would be my call, although I too have had a loose bolt clunk on me. The whining sound is common in many decrepit bearings.

Well, the clutch gave out whilst trying to bleed it, so I had to repair the master cylinder. I serviced the slave cylinder at the same time. The noise has not stopped but it got a lot less as moredunes said. will bleed it out again later and see what happens.

Bled it out again, and the noises stopped. only the whirring sound remains. will have to change the bearing.

I am going to bleed it again, too.still making the noise. I finally broke down and ordered a brand new throttle cable, it seems that all the junkers have sticky cables. If that doesn't fix my idle issues, i might drive it off a cliff out of frustration.