Vibration coming up through the shifter

[El_Mecanico]

Has anyone ever purchased a brand new Sachs clutch set and found to be out of balance? I'm getting a vibration at the shifter knob in 3rd and 4th gear. 1st and second are fine. Just finished having the engine and tranny rebuilt by a reputable shop. I installed the engine and tranny back in the car. Could it be an engine to transmission alignment? some bolts were bent so I ordered new ones. Also I did not fine any alignment dowel sleeves...are there suppose to be any? I know these are multiple issues but what could be causing the vibration in the shifter knob? Any recommendations would be helpful. Want to make sure its right before installing it back in.

[JAR0023]

Not sure I would suspect the clutch if the vibration is only in the 3-4 plane. I'd be lookng to see if I have my shifter/couple adjusted correctly and wondering about what happened during the rebuild of the tranny.


J

[area man]

if your engine/tranny mounts are old that would do it.

[skrufy]

Sure, a new clutch set could be out of balance- unlikely, but possible. I had several vibration issues in a 915 box that I put into my 930. One issue was bearings and a bearing race holder that had elongated- a known 915 issue. The other was the clutch set- it wasn't new at that time, but it only had about 2000 miles on the clutch. I took mine to Patrick Motorsports in Phoenix- sure enough, the balance was off. For piece of mind, you might take yours to a local speed shop capable of balancing cranks and engine parts to have them check it out. Your regular run of the mill machine shop or garage won't be able to do this for you- so find the one the racers go to..... I think Patrick charged me some $50 or so because they had to spend some time drilling the parts to achieve the balance they wanted- maybe within a quarter gram or so.

The engine and tranny mounts: if they are old/cracked/shrunk- replace them, as they can transmit sound and vibration for sure. Also check to make sure you have no metal to metal contact, as in tranny housing touching the torsion bar tube or emergency brake cable tubes touching, etc.- that will transmit a lot of noise and vibration.... The 5 speed 915 box is longer than the stock 4-speed 930 box, and I had metal/metal contact- talk about noise/vibration! - I used a ball peen hammer to "modify" the torsoin bar tube a bit- no more contact......

let us know what you find!

Tim

[El_Mecanico]

All mounts new but had them in before. Ill check the torsion bar when I re-install. I just wonder if the clutch spins faster when you shift to higher gears. I know the pressure plate is attached to the engine so if she doesn't vibrate in 1st and 2nd it should not be an issue in forth or fifth. Maybe as someone else said the shifter rod coupler needs fine tuning so it doesn't ride against the gate?

Andy

[FPB111]

Originally Posted by el_mecanico

all mounts new but had them in before. Ill check the torsion bar when i re-install. I just wonder if the clutch spins faster when you shift to higher gears. I know the pressure plate is attached to the engine so if she doesn't vibrate in 1st and 2nd it should not be an issue in forth or fifth. maybe as someone else said the shifter rod coupler needs fine tuning so it doesn't ride against the gate?

andy

+1

[RWebb]

replace old motor/trans. mounts

replace all 3 shift lever bushings & set it up carefully

feel the shift coupler while driving - how much vibration there?

may need to replace bushings in coupler

may need to rebuild shifter - see 911pcars info on blueprinting