Mart00SS

iTrader: (19)

So I bought a rotating assembly from a sponsor here and had them balance it a while back. Took my time and Built the motor with checking every clearance by the book with no problems. Now the engine is in the car and has a noticeable vibration at 1500 and 2400 rpm. Other than this it runs perfect. I would imagine that its not clutch related because I was using this same ls7 clutch on my old engine and it was smooth. Could it be this is an internal balance issue? Possibly balanced wrong? I know there really is no way to tell unless I tear it all back down and have the balance checked, but i'm hoping for some insight here.... thoughts?

01ssreda4

iTrader: (96)

IMO it could be a balancer issue. I would swap on a known good one to eliminate that as a possibility.

LilJayV10

iTrader: (39)

Is the vibration on the engine only or when driving?

I love these kinda threads.........

Duffster

iTrader: (103)

When you say built, are you saying you have a non-stock cam shaft in it? It's very common to have 'harmonic' issues with non-stock cams in the manual cars.....

Mart00SS

iTrader: (19)

Brand new gm balancer went on the new engine. Cam shaft is a tr224r. I know these threads suck but I'm at a loss, thought this engine would run rather smooth.

Mart00SS

iTrader: (19)

Also the vibration is more noticeable while driving but I can also duplicate it in neutral

01ssreda4

iTrader: (96)

Sounds silly but I would pull the trans and clutch and see if I could duplicate the vibration with just the engine running.

Darkman

iTrader: (2)

You can check/eliminate the driven accessories (water pump, alternator, power steering pump, etc.) by removing the serpentine belt temporarily.

LilJayV10

iTrader: (39)

Good idea.

Chasing down a vibration can suck.

Darkman

iTrader: (2)

The GM Service Manual (2005 CTS-V) has no fewer than 50 pages dedicated to vibration analysis and troubleshooting.

Mart00SS

iTrader: (19)

not a bad idea, I guess i'd have to leave the flywheel on there though so I could start the engine, so I wouldnt be able to rule that out though.


I seriously doubt any accessory on the front of the motor is causing this. Plus all the accessories are from my old motor which was running smooth.

kenp

iTrader: (9)

If you put the car in gear and depress the clutch while sitting still, nothing in the the tranny is turning. No need to go to all of the trouble of removing it to eliminate it as a source of vibration.

Mart00SS

iTrader: (19)

he meant remove the trans to remove the Pressure plate which is always turning with the engine.

01ssreda4

iTrader: (96)

Pressure plate and clutch is always turning. You could simply remove the assembly and replace with a know good stock flywheel/flexplate for starting purposes.

LilJayV10

iTrader: (39)

Any updates?

NVR_SPDS

iTrader: (39)

What kind of mounts are you running? Rubber, poly or solid?

RsSean

iTrader: (27)

Just a thought could you use a EVA2 to detrmine his problem rather quickly? Eva is a electonic vibration anaylis-SP

Mart00SS

iTrader: (19)

UPDATE! Well I had some clutch issues, so I pulled the trans and replaced the flywheel and clutch with a new unit. After that there was no change in the vibration, it was still there just as before. So tonight I decided to remove the brand new balancer I bought from NAPA that was on this new motor and install my original GM balancer with 200,xxx miles on it (that was known to be good from my old motor) and it is running SMOOTH AS SILK. Brand spankin new balancer from napa was bad. **** luck I suppose, but man am I happy it was just the balancer. Hope this can help others in the future.

01ssreda4

iTrader: (96)

Glad you found out the problem. When I just read it wasn't the clutch I was gonna say pull the front belt AND balancer off and recheck it. But you beat me to it.

LilJayV10

iTrader: (39)

That's great you figure it out. Thank you for posting an update.