bad vibration
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 6,226
Likes: 33
From: Morton illinois
St. Jude Donor '14-'15
bad vibration
When the car is parked and in Neutral, I rev it up to 1700RPM and the entire car shakes. Anything above or below and it runs smooth. What could this be? Motor or clutch problem? And when I say shake, I mean it sounds like the motor mounts arnt even there.
Also, on the highway, I get oen nasty vibration at about 85 to 95 then smooths back out at 100. It seems if I put it in neutral at speed, it goes away somewhat. The vibration almost has a rythem, its not constant. Im lost....
Also, on the highway, I get oen nasty vibration at about 85 to 95 then smooths back out at 100. It seems if I put it in neutral at speed, it goes away somewhat. The vibration almost has a rythem, its not constant. Im lost....
Melting Slicks
Joined: Aug 2000
Posts: 2,618
Likes: 5
From: Overland Park KS
Start with the easier stuff:
1) motor mount loose, broken
2) front crank pulley coming apart?
3) Clutch/flywheel issue.
If you get to #3 If in neutral, does the vibration change if you have the clutch pedal pushed to the floor vs. not? i.e. shaft in torque tube spinning vs. not.
1) motor mount loose, broken
2) front crank pulley coming apart?
3) Clutch/flywheel issue.
If you get to #3 If in neutral, does the vibration change if you have the clutch pedal pushed to the floor vs. not? i.e. shaft in torque tube spinning vs. not.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
A bit more info would help...When did this vibration start? Is it something new, and if yes, what happen just before it started this vibration? Is this an auto or manual trans car?
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 6,226
Likes: 33
From: Morton illinois
St. Jude Donor '14-'15
ok, so here is what it is...
Vibration at idle, I cannot figure out, I think that is a separate issue. So I will deal with that later
But, the bad one is speed dependant. At 85mph the car shakes horrible, it can be in any gear, with the clutch in or out, or in gear or out of gear. It seems this has been going on since the new motor, but I have had 2 sets of wheels and the same result has happened. Can the wheel bearings be going? or something speed related? I jsut cant see this as a wheel problem.
Any thoughts? im going crazy
Vibration at idle, I cannot figure out, I think that is a separate issue. So I will deal with that later
But, the bad one is speed dependant. At 85mph the car shakes horrible, it can be in any gear, with the clutch in or out, or in gear or out of gear. It seems this has been going on since the new motor, but I have had 2 sets of wheels and the same result has happened. Can the wheel bearings be going? or something speed related? I jsut cant see this as a wheel problem.
Any thoughts? im going crazy
Melting Slicks
Joined: Aug 2000
Posts: 2,618
Likes: 5
From: Overland Park KS
You know you need to have an alignment after a motor swap or even a clutch replacement. One or more cradles were removed and re-installed to swap the motor.
If you prefer to do all your own work like me, before you have an alignment I would re-torque all the rear suspension bolts (control arms to frame, shocks, cradle) and see if something was loose. If everything looks okay, check the front if you know they lowered the old motor out and raised the new motor in. If they did the swap from the top then the front cradle was probably loosened but not removed.
If you prefer to do all your own work like me, before you have an alignment I would re-torque all the rear suspension bolts (control arms to frame, shocks, cradle) and see if something was loose. If everything looks okay, check the front if you know they lowered the old motor out and raised the new motor in. If they did the swap from the top then the front cradle was probably loosened but not removed.
Safety Car
Joined: May 2006
Posts: 3,799
Likes: 1
From: Northern Virginia
St. Jude Donor '08
Another possibility that has not been mentioned is bad torque tube bushings.
If you get the vibrations with the clutch disengaged, then your problem would seem to be engine related. I have read of situations, where an improperly balanced clutch can cause vibration issues.
Good luck hunting down your problem. I know how fustrating it can be!
If you get the vibrations with the clutch disengaged, then your problem would seem to be engine related. I have read of situations, where an improperly balanced clutch can cause vibration issues.
Good luck hunting down your problem. I know how fustrating it can be!
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Here is list of typical sources of vibration. Knowing the type of vibration and matching it to this list can help identifiy the cause.
Torque tube issue (Propshaft issue)
Torque tube issue (Propshaft issue)
Normally will vibrate anytime the propshaft is rotating and will increase in amplitude with rpm
Harmonic damper issueNormally will vibrate at any engine rpm and will increase in amplitude with increase in engine rpm.
CV output shaftCan vibrate only when the car is moving, can be random in nature. On the Corvette, slight dip in the road causing a change on the suspension system height can trigger a bad CV to go into this vibration state. Once the car is stopped and the suspension system returns to a neutral position the bad CV can center, and the vibration will temporarily stop.
wheel/tireWill vibrate worse at a given speed. Go above or below the peak speed and the amplitude will decrease.
Wheel hubIf bent, will vibrate at any speed increasing as speed increase. If out of balance, will act much like a wheel or tire out of balance.
Pilot bearingThis one is a little harder to identify. It can be there all the time the engine is running or in some cases will come and go.
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Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 6,226
Likes: 33
From: Morton illinois
St. Jude Donor '14-'15
I put in the motor, and both cradles were off, along with all the suspension, and steering. I alwasy thought an alignment prob woudl jsut pull the car one way or another, not a crazy vibration. The car has had this since the install, but was ALOT worse after some launches at the track last Wed. I use a slick and dump the clutch at 5000 RPM, dead hook. SO this is why I thought of the torque tube. The clutch seems to work just fine. If i go any speed in first or 2nd gear, there is no vibration, its only about at 85 does it really show its ugly face, then it goes away at 100.....does this help isolate it more?
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Not propshaft if you don't also have the vibration in first or 2nd. My guess would e tire, hub, or brake rotor out of balance. It might also be one of the output shafts, except they normally will not go away with speed like the tire, hub or brake rotor will.
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 6,226
Likes: 33
From: Morton illinois
St. Jude Donor '14-'15
and brake rotors can be out of balance? I had stockers on, and new ones from DBA since. so I dont think its rotors
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
I just had the diff rebuilt at RPM with all very good stuff, so I doubt its that, cuz I had it before and after it was the same. but after the beating at the strip is when it came on much worse, so maybe a rear wheel hub?
and brake rotors can be out of balance? I had stockers on, and new ones from DBA since. so I dont think its rotors
and brake rotors can be out of balance? I had stockers on, and new ones from DBA since. so I dont think its rotors
Yes, I have seen rotors and hubs that are out of balance or even bent.
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 6,226
Likes: 33
From: Morton illinois
St. Jude Donor '14-'15
You may want to jack the rear tires off the ground and run it carefully and have someone watch the rear wheels/tires. See if one start vibrating. At least this will let you know which side to focus on. You shouldn't have to take it very high in rpm to see which side it is.
Yes, I have seen rotors and hubs that are out of balance or even bent.
Yes, I have seen rotors and hubs that are out of balance or even bent.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
The hub is the assembly that holds the wheel, and yes, it includes the bearings. They can be bent. When bent the vibration normally increases with speed. I doubt the hub is your issue because of your statement that the vibration decreases as you go past 85 mph. A bent hub is pretty easy to see if you have the wheels off the ground and rotate them.
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 6,226
Likes: 33
From: Morton illinois
St. Jude Donor '14-'15
ok, well.....I checked every wheel. there is 0 play when traying to move the wheel/tire....but I spun the wheel and both front tires seem to have a SLIGHT egg shape. i put a brick under the tire while it was up in the air and kept the tire away from it by about 1/16th of an inch, then spun it. I could see the light between getting bigger and smaller....how could both front tires get a wierd shape? is this from alignment?
also, when the motor was put in, I had every suspension component off, does this mean I needed a alignment after?
also, when the motor was put in, I had every suspension component off, does this mean I needed a alignment after?
Safety Car
Joined: May 2006
Posts: 3,799
Likes: 1
From: Northern Virginia
St. Jude Donor '08
ok, well.....I checked every wheel. there is 0 play when traying to move the wheel/tire....but I spun the wheel and both front tires seem to have a SLIGHT egg shape. i put a brick under the tire while it was up in the air and kept the tire away from it by about 1/16th of an inch, then spun it. I could see the light between getting bigger and smaller....how could both front tires get a wierd shape? is this from alignment?
also, when the motor was put in, I had every suspension component off, does this mean I needed a alignment after?
also, when the motor was put in, I had every suspension component off, does this mean I needed a alignment after?
If your tires were off the ground, I would expect than to distort, so that should not be the problem. Tires are flexible so their shape will change. If you watch someone drive, you will see the tires changing shape. However, double check to see that the actual diameters of the tires are pretty much the same. If they are off, this could cause vibration.
Out of curiousity have you tried inducing the vibration and then quickly pushing in the clutch to see what happens? I am thinking this would isolate the drivetrain from the motor, and might narrow down the source of the vibration.
Melting Slicks
Joined: Oct 2007
Posts: 2,383
Likes: 14
From: Kinston North Carolina
[QUOTE=VGLNTE1;1571790565]When the car is parked and in Neutral, I rev it up to 1700RPM and the entire car shakes. QUOTE]
Maybe I'm missing something here!!! What has this got to do with WHEELS, TIRES, HUBS, BEARINGS and ALIGNMENT?
Maybe I'm missing something here!!! What has this got to do with WHEELS, TIRES, HUBS, BEARINGS and ALIGNMENT?
Drifting
Joined: Jan 2008
Posts: 1,722
Likes: 138
From: Florida
St. Jude Donor '09
You have a vibration problem since the installation and yet you choose to take it to the track, interesting. My internet crystal ball tells me that your drive-line is coming back out and you will find some severe damage.