body rattle at 3K RPM

[doribak]

Hey all, got some problem in my car that i can't point to the cause.
i got hard vibration at 3K rpm the pedals and all the body shakes all around the place.
on lower then that its ok and above that it weakened.
on idle the steering column shakes more then the body.
i trying to figure if its the engine mounts or any other cause from the engine itself.

Thanks for the help

[6'9"Witha69]

RPM related vibrations are often caused by driveshaft balance and driveline angles. Do a search here as there has been a lot of discussion around this before.

[Mr.VENGEANCE]

Maybe improper pinion angle...

[Pro Stock]

Hey all, got some problem in my car that i can't point to the cause.
i got hard vibration at 3K rpm the pedals and all the body shakes all around the place.
on lower then that its ok and above that it weakened.
on idle the steering column shakes more then the body.
i trying to figure if its the engine mounts or any other cause from the engine itself.

Thanks for the help

Did this problem recently appear or has the car always done this ?,
if it has always done this it could be that the engine was improperly balanced and would be more apparent at different engine speeds (the same as tires that are out of balance will vibrate worse at different speeds, it could also be pinion angle or driveshaft balance but that would'nt explain the vibration at idle, it probably has something to do with engine balance or the clutch disc, if the engine was externally balanced the harmonic balancer could have slipped and effected the balance or a balancing weight could have come off of the flywheel. as far as the clutch disc goes, look to see if a piece of the facing has come off of the hub, that would also cause an imbalance at idle with the car out of gear. Take your car out of gear while standing still and bring the engine up to 3000 rpm and see if the vibration increases and then drive the car to 3000 rpm and push in the clutch and see in the vibration is reduced, in either case if it does these things your problem is probably from the clutch forward, if it does'nt do this the problem is probably from the drive shaft back but i doubt that this will be the case, hopefully I did'nt confuse you, I know what I am trying to say but might not be explaining this in a non confusing way, haha.


Good luck, Dale

[doribak]

ok cool sound like a good test! i will try it in few days when i will have time and i will report back.

another question, if the engine is not balanced how do i balance it?

thanks!

[Pro Stock]

ok cool sound like a good test! i will try it in few days when i will have time and i will report back.

another question, if the engine is not balanced how do i balance it?

thanks!

If it is out of balance due to the problems that I mentioned (balancer, flywheel, clutch disc) you would replace the broken part with a new part of the same design. the clutch disc can be replaced with the same type of disc made by any quality mfg. If the engine is a recent build ask the builder if the engine was internally or externally balanced and ask him if there is a chance that something was overlooked, hopefully you will be able to trust his answer.

[Gitter Dun]

If your steering coloum is shaking at idle, I'd check your motor mounts