50mikey

Recently my car has sprung a significant vibration in the 2200-2800 rpm range. Seems to lessen once warmed up or driven a bit. It does have the vibration throughout the rpm range its just most noticeable there. I feel it mostly through the shifter, but is strong enough that vibrates the steering wheel and gauge cluster (which caused rattles errr)

Car has factory T-5 with 15-25k miles after a HCI upgrade. Aluminum driveshaft. Factory rear end with new (15-25k miles) ring and pinion and axles.

joes90gt

After checking the obvious (tire balance, harm balalcer, etc.) check your driveshaft yoke/tranny tailshaft bushing for play. My yoke was hour-glass shaped from wear and the bushing had seen better days. I replaced them both and bye-bye vibration!

50mikey

Might sound like a dumb question, but how do you check the Harmonic Balancer? I have a feeling it could be that, only due to it being the only part on the engine that has been removed in 5 years.

Jfsram

First narrow down the protential problem to before or after the engine.

You say it's worst at 2500rpm. Drive 2500 rpm in 1st, 2500 in 5th then stopped hold it at 2500rpm in neutral.
If it only vibrates while driving in gear. Report back.
If it only vibrates in neutral try it with the clutch in and it gear, also at 2500rpm.

50mikey

Ok, so a little messing around with it I have come up with this.
1st, 2nd, 3rd, 4th, 5th gear all vibrates about the same amount at the specified RPMs.
At a stop, in gear with clutch in, it vibrates at the specified RPMs.
At a stop in Nuetral it vibrates at the specified RPMs.
So I'm guessing that means its most likely something from the Flywheel forward?

projectresto83

Sure is. Bring the motor up to TDC by bringing the rotor in the dizzy to the #1 cylinder and see where the timing pointer is pointing on the balancer.

50mikey

Ok put it to TDC this morning and it seems that it is sitting at 15 degrees past the 0 mark on the balancer. Also I noticed that there is nice shiny metal on the front inner ring of the balancer (might not make sense) like something scraped across it.

projectresto83

Well if you have the rotor pointing at the number 1 plug and it is at 15 then you have not spun the balancer (that is your aprox timing ) It might have slipped a little but even a little can cause it to vibrate a little. It kinda makes sense but try to get a pic of the shiny part

50mikey

Figured I would throw a pic in also. (keep in mind i went a hair past TDC while verifying with piston movement)

50mikey

im a little confused. I thought with the engine off and at TDC it should point at 0...with it running and using a timing light is where you would see the actual "distributor timing"


also cant get the correct angle to get a pic of the shiny area of the balancer at least its not as visible to the naked eye