PastorTom1
Well-Known Member
Well, the verdict seems to be IN on the 727 vibrations that were driving me NUTS on this particular build.
It's a swapped out 360/727 combo which was shaking the car apart, and destroying tailshaft bushings.
We had a new driveshaft built and balanced first.........installed it, but the vibration persisted.....very little change.
Next, we had a local shop check and change the tailshaft bushing and bearing...it sounded like marbles rattling around in there it was so bad....they chose to leave the bearing (WHY, I will never know....they didn't "feel" it needed changing).... After this, it felt better, but still had the chronic vibration. After just 100 miles or less, it started to rattle AGAIN. All they did was eat my money.
Next, I took it to CRT Racing Transmissions in Z-Hills.........He looked at the driveline angle going INTO the tail, and said he wanted to raise the tail by 1/2"..........OK.........if he says so. Next, he said the yoke shaft had not been properly cleaned and emery'd before the last installation...there were high spots, although very tiny, that were affecting the bushing........OK...if he says so. Next, he stated that he didn't like the bearing either (obviously, a man after my own heart)....so while he was there, he changed it and cleaned up the tailshaft. A new bushing also, and a re-install. Next, he stated that the black rubber rear mount was too soft for my application, and served to allow too much movement at the tail........He installed a more stiff nylon mount bushing, jacking up the tail by his 1/2" that he wanted, and took it for a test drive.
He called me this morning and I went to pick up the car. He told me that at about 50 MPH he felt a slight harmonic, but he felt it could simply be a driveshaft balance adjustment........he said I could have it checked at his favorite shop to see, but that it wasn't a big deal.
I paid him a total of $175.00 ( !!!!!!!! ) for the parts and work, and took the car out for a run through it's paces. I now get a very loed chirp into second gear at about 3/4 throttle, and another nice little one into 3rd. There are NO vibrations AT ALL that I can discern, although I CAN hear the slightest little harmonic over 50......but it's what I would call a "normal" sound for a high revving cruiser. (it could even be a very slight harmonic coming from the motor...but nothing I'm worried about).
Apparently this guy knows his beans. This cup of Joe I'm GLAD to pay $175. for.........It's like a new transmission........all worries gone........enjoyment and smooooooooth ride is BACK baby!!
I'd like to take my hat off to CRT and the gang. Great job diagnosing and finally FIXING the problem.
Again, they smoothed out the yoke and polished it......They changed the tail bearing and bushing........they raised the drive angle at the tail by 1/2" upward (to slightly increase it), and installed a stiffer nylon rear mount bushing. Problem solved. Happy Camper. End of story.
It's a swapped out 360/727 combo which was shaking the car apart, and destroying tailshaft bushings.
We had a new driveshaft built and balanced first.........installed it, but the vibration persisted.....very little change.
Next, we had a local shop check and change the tailshaft bushing and bearing...it sounded like marbles rattling around in there it was so bad....they chose to leave the bearing (WHY, I will never know....they didn't "feel" it needed changing).... After this, it felt better, but still had the chronic vibration. After just 100 miles or less, it started to rattle AGAIN. All they did was eat my money.
Next, I took it to CRT Racing Transmissions in Z-Hills.........He looked at the driveline angle going INTO the tail, and said he wanted to raise the tail by 1/2"..........OK.........if he says so. Next, he said the yoke shaft had not been properly cleaned and emery'd before the last installation...there were high spots, although very tiny, that were affecting the bushing........OK...if he says so. Next, he stated that he didn't like the bearing either (obviously, a man after my own heart)....so while he was there, he changed it and cleaned up the tailshaft. A new bushing also, and a re-install. Next, he stated that the black rubber rear mount was too soft for my application, and served to allow too much movement at the tail........He installed a more stiff nylon mount bushing, jacking up the tail by his 1/2" that he wanted, and took it for a test drive.
He called me this morning and I went to pick up the car. He told me that at about 50 MPH he felt a slight harmonic, but he felt it could simply be a driveshaft balance adjustment........he said I could have it checked at his favorite shop to see, but that it wasn't a big deal.
I paid him a total of $175.00 ( !!!!!!!! ) for the parts and work, and took the car out for a run through it's paces. I now get a very loed chirp into second gear at about 3/4 throttle, and another nice little one into 3rd. There are NO vibrations AT ALL that I can discern, although I CAN hear the slightest little harmonic over 50......but it's what I would call a "normal" sound for a high revving cruiser. (it could even be a very slight harmonic coming from the motor...but nothing I'm worried about).
Apparently this guy knows his beans. This cup of Joe I'm GLAD to pay $175. for.........It's like a new transmission........all worries gone........enjoyment and smooooooooth ride is BACK baby!!
I'd like to take my hat off to CRT and the gang. Great job diagnosing and finally FIXING the problem.
Again, they smoothed out the yoke and polished it......They changed the tail bearing and bushing........they raised the drive angle at the tail by 1/2" upward (to slightly increase it), and installed a stiffer nylon rear mount bushing. Problem solved. Happy Camper. End of story.
