Balanced Driveshaft?
Thread Starter
Racer
Joined: Jul 2004
Posts: 400
Likes: 1
From: California
Balanced Driveshaft?
is the C3 driveshaft internally balanced? or pre-balanced? when i was installing the tranny i got a bad vibration when i put it up, then i turned it around and it lessend, but was still there. then i had my friend take a look at it, and he seem to fix it. just wondering how GM did this one?
Le Mans Master
Joined: Jan 2004
Posts: 8,295
Likes: 30
From: one night in Bangkok you are never lonely
Question How did your friend fix the problem? Also did you feel the vibration at high speeds only? I am having vibration problems and was wondering if I have a similar problem. 
Pro
Joined: Aug 2003
Posts: 677
Likes: 5
From: Cary North Carolina
They were externally balanced. You should be able to see the balancing weights at each end. I got new spicer U-joints and the shaft re-balanced and painted for @ $80 at a local drive shaft shop.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
externally balanced with the yoke attached.....so if you took it off and didn't notice/mark the correct yoke position to the driveshaft...it could be installed "wrong"...your friend probably took off the drive shaft turned it and either by luck or by seeing the balancing marks lined it up correctly.....
Team Owner
Joined: Aug 1999
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SPARTAN
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Yup. They're externally balanced with a welded-on weight at each end near the yoke. Not sure what your friend could have done to fix it. 
Thread Starter
Racer
Joined: Jul 2004
Posts: 400
Likes: 1
From: California
well when i put it up and in, we had it wrong, the driveshaft needed to be flipped, so i flipped it and put it back in. that corrected most of the vibration at about 25+ mph. then i still wasnt satisfied and i flipped the yoke in the tranny, and that made it worse, so i flipped it yet again......then my friend rechecked my work and i guess the straps werent asd tight as they should have been. lol
Team Owner
Joined: Jul 2004
Posts: 40,412
Likes: 792
From: Redondo Beach, California
As far as I know, only the factory 327's were internally balanced. For performance applications my understanding is that all cranks must be internally balanced. 350 cubic inches and above were externally balanced. I think they need to be internally balaced. A 350crank can be internally balanced with added heavy weights added to the crankshaft throws.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by 68/70Vette
As far as I know, only the factory 327's were internally balanced. For performance applications my understanding is that all cranks must be internally balanced. 350 cubic inches and above were externally balanced. I think they need to be internally balaced. A 350crank can be internally balanced with added heavy weights added to the crankshaft throws.
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Pro
Joined: Aug 2004
Posts: 732
Likes: 1
From: Green Lake Wisconsin
externally balanced...my dad had a pickup truck may years ago that had a vibration that got worse the faster the truck went...turns out the driveshaft was out of balance...the gm fix? put a hose clamp on it at the correct spot...
ever had a issue with the hose clamp slipping or anything, and he had that truck a looong time...
ever had a issue with the hose clamp slipping or anything, and he had that truck a looong time...