viberation

[fiat218]

well i need help.
72 124, i got a viberation at 70 mph, i had the ujoints replaced and flex and hanger bearing
still did not solve the problem. went and rotate and balance the tires, still the problem is there

4th gear, vib is at 62 mph
5th gear , vib is at 72,

WHAT is going on?

[RRoller123]

Check engine and tranny mounts? The engine mounts on my '80 were found quite loose when I bought it last Fall. Made a big difference in smoothness when I tightened them.

[fiat218]

Check engine and tranny mounts? The engine mounts on my '80 were found quite loose when I bought it last Fall. Made a big difference in smoothness when I tightened them.

ok thanks

[mgbgtn]

The early Miatas were famous for getting a vibration at 60 mph and it was caused by tire pressure being too high or different between tires.

[majicwrench]

Vibration is something spinning, not motor mounts (unless they are spinning;)
Tires, drivelines produce vibration. Engine can too (crank, flywheel spinning), but it will do it revving engine at a stop, so not that.
Driveline spins 3-4 times more rpm than tires, and thus driveline vibrations USUALLY show up at a lower speed (under 50mph) than tire vib.
Most high speed vibrations are tire balance or poor tires. Air pressure won't do it.
Did whoever balance tires test drive car??
Did who ever replace u-joints test drive car?? What did they have to say about vibration?
Cheap tires?? Aftermarket rims??

[fiat218]

Vibration is something spinning, not motor mounts (unless they are spinning;)
Tires, drive-lines produce vibration. Engine can too (crank, flywheel spinning), but it will do it revving engine at a stop, so not that.
Drive-line spins 3-4 times more rpm than tires, and thus drive-line vibrations USUALLY show up at a lower speed (under 50mph) than tire vib.
Most high speed vibrations are tire balance or poor tires. Air pressure won't do it.
Did whoever balance tires test drive car??
Did who ever replace u-joints test drive car?? What did they have to say about vibration?
Cheap tires?? Aftermarket rims??

yes u joints and bearing and flex was all replaced last week
balance and rotate yesterday, tires are a summit brand , not a aftermarket rim

tires are cupped some what, so rotating them would help ( i thought )
maybe a new set would take the vibration out then. or what

[majicwrench]

Again, did tire shop test drive car?? Who did ujoints?? Did they drive it?? Cupping won't cause vibration, although it can make it a little rough feeling at low speeds.
Glad to see you have OE wheels. Take tires back, still shakes, see what they say.

[fiat218]

Again, did tire shop test drive car?? Who did ujoints?? Did they drive it?? Cupping won't cause vibration, although it can make it a little rough feeling at low speeds.
Glad to see you have OE wheels. Take tires back, still shakes, see what they say.

my mechanic did the drive line, he had the car on jack stands and there was a slight vib he said but nothing as it was before. but when i drove it it was all the same
no the tire shop did not drive it
i will asked the tire shop what they think

[majicwrench]

If vibration didn't change with ujoints etc, that would make me think it is NOT a driveline issue.
Did it change when you rotated tires?
Is vibration in steering wheel, or in your butt?

[fiat218]

If vibration didn't change with ujoints etc, that would make me think it is NOT a driveline issue.
Did it change when you rotated tires?
Is vibration in steering wheel, or in your butt?

SMOOTH front end, no vib in the steering at all,either at low speed or high, been up to 105 mph, not even a stir in the steering other then normal
no change in doing anything, drive line is all new,other then the drive shaft. so cal mark said one time that it is possible the drive shaft is out of balance, how would u know that?
other then that, i have no clue in what to check,or change !!
how about the yoke on the rear ?
thanks for helpng me

[majicwrench]

Hmm, so nothing has changed anything...... OK, so at what RPM is it vibrating?? Go for a drive and take note. Now, Will it vibrate sitting still reving the engine to that same RPM??
Sure, it's very possible drivelin out of balance, or bent. you can balance on car or send out to a driveline shop. First, try above.

If steering wheel smooth before rotating, and still smoother after rotating, and car still vibrates, would think it is not tires.
Rev engine. Report back

[fiat218]

Hmm, so nothing has changed anything...... OK, so at what RPM is it vibrating?? Go for a drive and take note. Now, Will it vibrate sitting still reving the engine to that same RPM??
Sure, it's very possible drivelin out of balance, or bent. you can balance on car or send out to a driveline shop. First, try above.

If steering wheel smooth before rotating, and still smoother after rotating, and car still vibrates, would think it is not tires.
Rev engine. Report back

let u know the results in the morning
how do u balance the drive shaft on the car?

[rlux4]

That's the "take it to a driveline shop" part of Kieth's post. I just had mine checked (it was good) at a good driveline shop after my recent vibration that ended up being the front U-joint being off center in the yoke.
Ron

[fiat218]

That's the "take it to a driveline shop" part of Kieth's post. I just had mine checked (it was good) at a good driveline shop after my recent vibration that ended up being the front U-joint being off center in the yoke.
Ron

speaking of drive shafts, i have another one from the 69, would that fit the 72. , i can measure some how to i guess
thanks

[fiat218]

Hmm, so nothing has changed anything...... OK, so at what RPM is it vibrating?? Go for a drive and take note. Now, Will it vibrate sitting still reving the engine to that same RPM??
Sure, it's very possible drivelin out of balance, or bent. you can balance on car or send out to a driveline shop. First, try above.

If steering wheel smooth before rotating, and still smoother after rotating, and car still vibrates, would think it is not tires.
Rev engine. Report back

let u know the results in the morning
how do u balance the drive shaft on the car?

majicwrench!!! well doing as u suggested, the car in the driveway, e brake on,rev at 4000 rpm,,viberation is there, driving it ,4000, viberation is there, so that tells me that there must be what? loose/ bad mounts,
can't be out of balance in the engine? can it