Vibration...Need help

[slvr302]

I have a 93 with Vortech. I have a vibration in my drivetrain and I can't figure out what it is. Everything is basically new in the car.

Block is a new DSS Pro Bullet
Stock Harmonic balancer that is new from my old motor
Tremec 3550 with 7500 miles on it
FRPP steel flywheel new from old motor
SPEC Stage 3
FRPP Driveshaft

I have eliminated the driveshaft as being the issue because I swaped it out with a good one from my buddy's car. Vibration happens when car is not moving thus that eliminates the rear as causing it.

If I "blip" the gas lightly in neutral with clutch engaged you can feel and hear the vibration in the shifter. It is like something is knocking. If clutch is disengaged (pedal to the floor) it becomes harder to feel or hear the vibration but nevertheless it is still there.
If I "blip" the throttle under the hood you can feel the vibration in the throttle body!
When driving in every gear at some point, depending on which gear I am in and if I attempt to tach the car up, the entire car vibrates as if it is going to fall apart. 1st, 2nd, and 3rd starts to really vibrate at about 3000 rpms. If I put the car in say 4th when it should be in 3rd (lug the motor) and I give it light gas, you can feel and hear the knocking easily.

Basically at lower rpms it is like a knock and you can feel it. As the rpms get higher knock becomes vibration I suppose because everything is spinning much faster.
Clutch is just passed the break-in period and motor has about 600 miles on it now. I got on the car hard a couple of times while driving down the highway and also from light to light one day to see how everything was working. Last time I got on it from a dead stop, the next time I went to drive off that is when I noticed the issue.
What does it sound like my problem is and is there a way to isolate the problem to the motor or clutch/trans?

 

[88hatchblack]

you don't have solid motor mounts do you?

 

[88hatchblack]

my friends dad has a 351 fox with solid motor mounts and it vibrates alot

 

[slvr302]

you don't have solid motor mounts do you?

NO

 

[Blandnuts]

Since the sound is, "harder to feel or hear" when the clutch is disengaged (pedal to the floor) I would assume it is the pressure plate. Maybe someone else has an idea, but that seems to be what the problem is. I thought it could be something else but there wouldn't be a difference with the clutch on or off.

Maybe the bolts just need to be tightened up.



fred

 

[slvr302]

Since the sound is, "harder to feel or hear" when the clutch is disengaged (pedal to the floor) I would assume it is the pressure plate. Maybe someone else has an idea, but that seems to be what the problem is. I thought it could be something else but there wouldn't be a difference with the clutch on or off.

Maybe the bolts just need to be tightened up.



fred

I an under the impression that with the clutch engaged, the input shaft on the trans is now able to transmit any vibration easier from the motor (if something with the motor has anything to do with it)

 

[Blandnuts]

I an under the impression that with the clutch engaged, the input shaft on the trans is now able to transmit any vibration easier from the motor (if something with the motor has anything to do with it)

When the pressure plate is disengaged from the clutch (pedal to the floor), the motor no longer has movement on the transmission/ inputshaft.

When the pressure plate is engaged, the motors vibration is transmitted through the input shaft. So you are correct in that manner, but if the vibration is gone when the clutch is pushed and present when not, it seems to be in the drivetrain not the motor.

If it's the motor, I would check simple things like the water pump, altenator stuff like that... Basically anything that runs off the belt or is spinning. If these things pass then like I mentioned earlier, it's probably the pressure plate.




fred

 

[gt90stang]

slvr302,

Just because the DS is perfectly balanced does not mean that the entire rotating assembly is in balance, there are many factors. Check this out:
http://home.hiwaay.net/~ctfrench/procedure.htm

Good Luck, Don

 

[slvr302]

When the pressure plate is disengaged from the clutch (pedal to the floor), the motor no longer has movement on the transmission/ inputshaft.

When the pressure plate is engaged, the motors vibration is transmitted through the input shaft. So you are correct in that manner, but if the vibration is gone when the clutch is pushed and present when not, it seems to be in the drivetrain not the motor.

If it's the motor, I would check simple things like the water pump, altenator stuff like that... Basically anything that runs off the belt or is spinning. If these things pass then like I mentioned earlier, it's probably the pressure plate.




fred

This sound is there either way but just easier to hear and feel when the clutch is engaged. The sound doesn't go away wehn the clutch is pressed (disengaged)

 

[revelationz]

I have the exact same problem with mine it vibrates like hell no matter what gear its in, weather im driving it or not and it doesnt matter if the clutch is engaged or disengaged and you can really notice it around 2000+ rpm. i took it to this guy who's real big with mustangs around here and he said that my clutch wasnt adjusted correctly. what had happend was that i replaced my adjustable clutch cable after it broke with a stock oem non adjustable one (due to no cash) and he said that, that was the problem, i dont know how to adjust a stock one at all or even if i can hopefully that will help i hate seeing a bad mustang just sit like mine is due to shortage of funds.

 

[UnderPressureGT]

bro you said youe car is running hott and you have to get a new fan clutch... i wanna put money on that .. Same thing happened to me and that was the problem.. someone made a similar thread like this, and i told him to look at the fan and sure enough that was it.... when you drove me in your car, it reminds me of exctaly what mine was like when that happened...... even if you dont think thats it... take the belt off and rev it up.. 2 seconds aint gonna kill ya... call me up and let me know what happens