Alright first of all i want to say hi since im new. Now to the questions,
We have a 66 mustang with a freshly rebuilt 289. The motor was taken to a machine shop and we had everything done. We finally got the motor running and it had a bad vibration when you hold up the rpms a bit, so we thought the tranny was installed wrong so we took it to the transmission shop that rebuilt the tranny in this car a while back(couple thousand miles ago with old old motor). They fixed a few small things but said everything was line up correctly. I was wondering first of all do higher lobe cams cause vibrations? also does having a poly tranny mount make it a lot worse vibrations wise? There was a brand new harmonic balancer installed with the new motor and the flexplate was brand new with the tranny rebuild and worked great with the motor. I just tried installing a used HB from a local shop and it didnt really seem to help the problem. I can really only feel these vibrations from inside mainly on the steering wheel. when i hold it at the same rpm outside i dont feel any excessive vibrations. I know the HB is 28oz for sure and I dont see why the flywheel would all the sudden come out of balance. Im trying to fix this and also trying not to run it just incase it turns out to be something wrong, i dont want to trash the bearings in the motor. Any help would be greatly appreciated!
We have a 66 mustang with a freshly rebuilt 289. The motor was taken to a machine shop and we had everything done. We finally got the motor running and it had a bad vibration when you hold up the rpms a bit, so we thought the tranny was installed wrong so we took it to the transmission shop that rebuilt the tranny in this car a while back(couple thousand miles ago with old old motor). They fixed a few small things but said everything was line up correctly. I was wondering first of all do higher lobe cams cause vibrations? also does having a poly tranny mount make it a lot worse vibrations wise? There was a brand new harmonic balancer installed with the new motor and the flexplate was brand new with the tranny rebuild and worked great with the motor. I just tried installing a used HB from a local shop and it didnt really seem to help the problem. I can really only feel these vibrations from inside mainly on the steering wheel. when i hold it at the same rpm outside i dont feel any excessive vibrations. I know the HB is 28oz for sure and I dont see why the flywheel would all the sudden come out of balance. Im trying to fix this and also trying not to run it just incase it turns out to be something wrong, i dont want to trash the bearings in the motor. Any help would be greatly appreciated!