DRM C5

I had a new LS6 engine built last September by a Corvette race car driver who competes in the World Challenge GT. My corvette is an automatic. There is a vibration at 3500 RPM in all gears, including when the car is revved in nuetral. This suggests that there's an issue with the engine. I am assuming that the LS6 short block was balanced at the factory yet maybe not. The heads are AFR 205 and cam is the G5-x3. Can anyone tell me how serious this condition may be? What might be a possible fix? I am hoping the builder will provide some warranty to fix the problem. What could happen to the engine if the vibration/harmonic is not corrected?

I appreciate everyone's input.

Paul

Gman2002Z06

Something else to consider, seeing that you are an auto...It may be possible that the vibration is coming from an imbalance in the torque converter...Also, take a look at all the accessory (power steering pump, a/c, etc) brackets and make sure that something is not loose or cracked...

Vibrations that occur at a certain rpm are, as you say, usually harmonic related...I would think that an imbalance in the engine would show up more as a roughness, than a vibration...

Also, make sure that the harmonic balancer has not loosened itself up...That thing is supposed to have the nut torqued to 350ft-lbs or something like that...

I am running a G5X3 and the only vibration, so to speak, is just a lumpy idle...Other than that, the engine is a smooth as silk...

Good Luck...

Peace...Gman

firechicken2k

I agree about the torque converter bit
Actually, I'd place a $20 bet that that is what it is

very simple fix too... but you need to drop the tranny (obviously) for it

good luck