I'm tryin to trace a vibe problem (which I'm sure isn't the d/s, tires, or rims) and with the other advice in a previous thread,
( http://web.camaross.com/forums/showt...142#post654142 )

I think it may be the flywheel. Could someone tell me if they are zero balanced or not? Its a '95 T/A M6 (was an A4 )

Thanks in advance!

 

no..they have little balance weights on the back, bolted or riveted in place.

 

Yeah, only chevy 400's weren't zeroed. All 350s are internally balanced. vibrations: you said it wasnt:
-Wheels...That means you've checked for roundness, lumps in the tread, balance, brakes
-A-arms, I've seen these get bent in very extreme cases by wacking a NYC street sized pothole
-Belt tensioner: Seen a weakening belt tensioner cause a wacky vibe one time
-plugs, wires, opti, coil: Had a vibration that I SWORE was my torque converter end up being a bad optispark causing cylinders to fire just slighty off time, making a rough running engine
-motor mounts, a broken or sagging one might cause a vibe
-tranny mount, the factory ones suck
-exhaust touching the chassy somewhere: my MAC I used to have touched when it went over the axle
-axles: seen a mustang w/ a bent axle (from a curb) have a wacky vibe
-torque converter: forgot if your car had one or not. Balooning causes poor balance.......I'll post again if I think of more.

 

That's not correct, actually. The LT1 is externally balanced, against the flywheel. So the flywheel is not zero/neutral balanced.

Dave

 

Hruh? This would be news to me.
How would the LT1 be any different that L98s and other 350s? I've built quite a few LT1s and a few L98s. I've never noticed a weighted flywheel. I suppose I might be incorrect, but can you back this up?

 

Yes, they do have a counterweight on them..I had to have mine nuetrally balanced when I installed the 383 because my new motor is internally balanced..

Cody

 

They are correct, most L98's should also be this way. If i'm not mistaken all once piece rear main seal SBC's (87+) are externally balanced on the rear while neutral balanced up front.

 

He is correct ALL one piece rear main seal cranks are Externally balanced!!!!!!

Some people derive their information from catalogs like Jeg's and Summit which advertise things like LT1 internally balanced dampeners. They might incorrectly assume that is a stock replacement. Of course we know better. Same deal with con rods. Some people assume because they advertise rods for 2.100 rod journals that the rods have a 2.100 rod journal but that is not the way the rods are. Don't assume anything from catalogs.

 

The dampers are neutral balanced. Its the flywheel/flexplate that isn't.

 

Thanks for the correction guys and my apologies for the false info to the original poster.
Last night I crawled under my car and looked....weights on the flywheel when I dropped the inspection plate....what do you know. Then I started looking through my various pics of engines that I've installed or built or helped on for people, and sure enough....weights on the flywheels...except for on a 396 that I installed. THAT, was the motor that I was thinking of. Then I called that guys and realized that that was an SFI approved aft. market plate and indeed, he'd had the motor internally balanced.
Well, everyone's gotta be wrong sometime....

 

Check both your front wheel bearings. I have a vibration at hwy speeds and someone told me to check the wheel bearings. So I jacked up the front end and spun both tires and pulled them back and forth (check for and play) but they were both tight as hell. I couldn't think of what else it would be so I took off the front left wheel bearing assembly (only 4 bolts) and compared it to the new one. Wow, what a difference between the 2. The worn out one was harder to turn than the new one. Put it all back together and no more vibrations .

 

So after I build my 383 I have to get a LT1 zero balanced flywheel? Im planning on getting an internal balanced. Can I use the stock balancer on the front since u said it was zero?