Vibration - Not the Good Kind

[Kevin71]

Well I have been a the same problem for almost three years.  I put a tremec 5 speed kit in from The Driven Man.  I have looked at everything.  New rear springs drive line angles.  All mounts are new polyerthanes.  Driven man is now saying pull the trans and clutch.  Put the bellhousing and starter back on and crank it up does that solve it. If not add the pressure plate and try again.  They think it is the flywheel or pressure plate.  I don't know if this helps.  I'll let you know next week.  I hope to get time to work on it this week end.  However did run into a guy that had a 89 mustang the other day and he had similar problem after putting a new center force pressure plate and clutch.  He had the flywheel turned too.  Got alot of vibration after that and sold the car. 

[ek3]

when did this start . is the engine new? or has this started after only a trans change ? i have seen plenty of engines with out of balance issues that are new!  an rpm specific vibration is usually  balance related..  eng, harmonic-bal, clutch /flywheel or driveshaft . this goes away at higher rpms /mph correct?

[ek3]

I know you said Denny's built the driveshaft, but the symptoms sure sound like the problems I used to have until I had my driveshaft rebalanced.  Just my 

   

[EddieE]

when did this start . is the engine new? or has this started after only a trans change ? i have seen plenty of engines with out of balance issues that are new!  an rpm specific vibration is usually  balance related..  eng, harmonic-bal, clutch /flywheel or driveshaft . this goes away at higher rpms /mph correct?

Yes, the vibe is in the narrow range between 3000 and 3500, and it's only under heavy acceleration.  No vibe in neutral with the clutch out, no vibe in light driving.  It also smooths right out above 3500.  I have the rev limiter set at 5500 and I don't really run the car hard very often.

[Kevin71]

Does it vibrate when it's in nuetral at 3000 to 4000 rpm's   Or with the clutch in.  Did you have the flywheel turned for a new clutch disk?  I got a new flywheel and clucth assembly.  Come to find out the flywheel center hole measured 2.14 and the crank is 2.16.  When I bolted it on yea it was tight but I thought is was supposed to be.  Anyway it didn't seat right and flywheel mushroomed a little.  Caused all kind of vibration.  Has taken forever to figure it out.  Good luck.  Let's us know what it turns out to be.

[ek3]

Yes, the vibe is in the narrow range between 3000 and 3500, and it's only under heavy acceleration.  No vibe in neutral with the clutch out, no vibe in light driving.  It also smooths right out above 3500.  I have the rev limiter set at 5500 and I don't really run the car hard very often.
[/quote                                                     so, it is just like a tire when it shakes at 60 mph to 65 mph but is fine at speeds above that  or below ! it passes through the point where the imbalance is .......misaligned driveshaft yokes ,missing weights from driveshaft as, it does not do it in neutral.. i have seen  the wrong  harmonic balancer or  a  warped flywheel or incorrect  balance on a flywheel that wasn't noticed unless loaded ,or even a-- bent yoke-- .  . find a known Good shaft and compare it installed. my local machine shop charges 75$ to cut and re-balance a shaft.