bigoneZ28

Hi guys. Recently my car has developed what seems to be an engine vibration. I initially thought it was drive train but
today I parked the car and slowly took the revs up. It seems to shudder from about 1800 to 4500 rpm.
Could this be sign of an internal problem, external such as torque converter/flywheel or something as simple as bad plugs &/or wires?

Anyone had such an experience? Any ideas?
Sorry for the long post & if post in wrong section.
Many thanks

Viper

iTrader: (6)

Busted tranny mount possibly. Inspect, then if needs replaced I recommend poly urethane.

bigoneZ28

Thanks. I'll check it over the weekend.
Anyone else with any ideas?

Mustang Hat'r 2

iTrader: (24)

How does the engine run sound? A cylinder going down/not firing will make the car shake like SOB, I would also check motor mounts, and the crank pully could be coming loss and wobbling.

robertbartsch

A primary source for this type of proble is the flywheel...do you have an auto? ...if yes, the flywheel could be cracked...this causes a whicked vibration that sounds like the motor has thrown a rod!!!

Pro Stock John

iTrader: (34)

Make sure the car is running on all 8 cylinders.

Make sure you don't have a broken motor mount.

bigoneZ28

Hi guys, I was busy at work the last few days and just got a chance today to take the Z in to the garage.
We put it on the lift and checked trannny mount, u joints, crank pulley, etc. All seemed okay. The engine mounts appear a bit mushy but not obviously broken. Also checked the torque converter bolts and they were tight(spinning the flexplate and looking thru inspection hole).

We checked the TR6 plugs which appeared in good order. Could the coils/wires (original be going bad-wires look good)?

Any suggestions on where to go from here? Many thanks.

robertbartsch

...PULL the tranny and inspect the flywheel...I bet it is cracked... some cracks are impossible to see with the tranny and motor bolted together...

...if you have a lift it should not be too bad...

robertbartsch

...is the bad vibration more of less evident when the tranny is in drive vs. neutral? If more evident when in drive, then I really think it is a busted flywheel...

bigoneZ28

Actually, the vibration is more evident in "park" slowing taking revs from 1500 to around 5000...getting more so as the revs go up.

Pulling the tranny is a pita

bigoneZ28

I didn't get a chance yesterday to do anything with the car and as the garage owner is 7th Day Adventist, it will be Monday before we can get back at it.

Is cracking the flywheel a common issue with the LS1 cars, especially after a high stall converter? Do you think that the converter(TCI Streetfighter [3000 stall])itself could be an issue?
I appreciate all input from you guys. Thanks

robertbartsch

...don't know about whether a cracked flywheel is common in LS1 cars or if a high stall contributes to this....

bigoneZ28

Hi guys, I've installed a ASP underdrive pulley/damper and the vibration is still there.
Also disconnected the converter from flexplate and
vibration still there. Im beginning to thing that the flexplate is the problem, but would like to have another on hand first(dealers don't really stock such items here on island). I read that TCI was bringing out a heavy duty flexplate for LS1. I'd rather install that than another stock plate, if indeed the plate is the problem.
Anyone aware of a release date of the TCI flexplate?
Car is not my only vehicle and with my work schedule, I have not been rushing it...so please, don't any of the hard core wrenchers think I'm lazy

robertbartsch

Flexplate = flywheel ...sounds like it is cracked to me...

robertbartsch

Some of the after-market torque converters have a thin hub (about 2")that fits inside the flywheel...it acts as a centering piece upon assembly...

...I have seen the hubs break...this also gives the same result as a broken flywheel...namely, bad vibes...