rb26 vibrations. need expert advice.

[240zdan]

i am experiencing vibrations in both my clutch pedal and shifter at higher rpm above 4-5000. the problem is apparent when in gear and moving. it does it in any gear, so i dont think its a driveshaft vibe. the harmonic damper seems to be in good shape but does wobble slighlty at idle. (no more than my friends brand new STI, though). The motor was involved in a front end collision which destroyed the water pump and destroyed the original harmonic balancer. I thought about the crank being bent, but the way I beat on the motor, im pretty sure it would have blown by now. there are no metal shavings in the oil or irregular noises coming from the bottom end.The throwout bearing is a bit noisey but i can feel the vibration in the shiftknob with the clutch released so i dont think its causing it. obviously if the vibration is strong enough to be able to feel it in the clutch pedal and shifter, i know there has got to be something wrong.

anyone have any ideas? whats causing vibration at higher rpms in any gear?my next assumption woudl be to pull the trans and check the flywheel face runout? maybe the motor had fallen on the flywheel during transportation, throwing it off whack?i guess i do have a few things to check but my real question is, what else is a symptom of a bent crankshaft? would there be any oil leakage from the front seal? i have absolutley none.
Modified by 240zdan at 10:48 PM 7/31/2009

[Shocker]

Check the rear bolts on your driveshaft to diff. I bet they are loose. Use blue lock tight when re-installing them.

[HxC_Nismo]

i honestly dont think its the flywheel since it only vibrates while in gear and at 4-5k rpm. if it was the flywheel you would feel the vibration in neutral at 4-5k rpm. i would check the drive shaft like shocker said, check your transmission mounting to make sure its lines up with the diff and not sitting off.

[matafied]

i would also check and make sure your trans isent making contact with your trans tunnel. i had this happen to me one time and after investigating i found the trans rubbing the tunnel. i dropped the trans mount and pounded alittle room with a sledge and BAM, the vibration was gone. idk worth a try

[240zdan]

thanks for all the replies, im going to try those things

[240zdan]

turns out the crossmember i made was hitting one of the bolts that bolt the transmission mount to the transmission. made some clearence and vibration in shift knob is gone, but remains in clutch pedal. im assuming its the worn out throwout bearing. only felt when pushing in the clutch.

[silviasgp06]

if for some reason your using a modified stock 2 piece drive shaft make sure the center carrier bearing doughnut() is not upside down.

[240zdan]

its a single piece, the motor is in a 240z.i get a huge whine/howl on acceleration in the diff, im pointing the rest of the vibrations to that, and the wheel bearings.

[Fibre guy]

Another rb26 240z Pics please!

[240zdan]

yes it changed my driving life... best car ive ever owned, period