LT1-LT4 Modifications 1993-97 Gen II Small Block V8

lt1 flywheel

Old 07-20-2010, 04:26 AM
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Default lt1 flywheel

i have a vibration that feels like it is in my trans. T56. i pulled out the trans. and was looking at the clutch and flywheel. i was under the impression that the lt1 motor was a enternaly balanced motor which would make the flywheel 0 or neutral balanced but my flywheel has a small weight on it. so my question is is it ballanced with the wieight or with out the weight and then the weight is put on? and what is the weight for. thanks
Old 07-20-2010, 04:38 AM
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lt1s are internally balanced in the front and externally balanced in the rear hence the weighted flywheel
Old 07-20-2010, 10:23 AM
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I had this problem. Did they resurface? Is ur clutch pressure plate smooth or is it a little bumpy? Did u balance ur pressure plate?
Old 07-20-2010, 11:34 AM
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On my next clutch, I plan on replacing the flywheel since this one has been turned at least 3 times.

So if if I buy a brand new LT1 flywheel from shop a,b or c. Will it have the same weight correction as my original one? Or does the original one have to be analyzed and then the new once corrected to match the original?

I dont understand how one can properly balance a flywheel without taking into account the rotating assembly.
Old 07-20-2010, 11:36 AM
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Nope, any out of the box flywheel designed for a 93 - 97 LT1 will work.

Personally, I could not be happier with my Al flywheel from RAM.
Old 07-20-2010, 11:58 AM
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All lt1 flywheels will work trust me ur vibration will go away. 3times is a lot. I had mine cut 3times and it started to vibrate,until I bought a new one.
Old 07-20-2010, 12:00 PM
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Originally Posted by alexcoreas
All lt1 flywheels will work trust me ur vibration will go away. 3times is a lot. I had mine cut 3times and it started to vibrate,until I bought a new one.
The only vibe I have is in 5th and 6thgear (mostly 6th) at 85MPH+. Rest of the gears and regardless of RPM or speed are smooth as silk. I dont see how that can be flywheel related but I cant rule it out.
Old 07-20-2010, 12:05 PM
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The first thing that comes to mind on your year is an unbalanced driveshaft. There was a TSB on it a decade ago.

If you have the stock shaft, I'd bet money on it being the problem.

The tranny is easy to diagnose - At 85 mph, when it vibrates, put it in neutral. If it stops, it's in the tranny (but I don't think it is).

If it's not the flywheel (which if it was resurfaced it could be) it's the DS.

Also, no chance a weight fell off one of your wheels, right?
Old 07-20-2010, 12:28 PM
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Originally Posted by Al 96 Ram Air T/A
The first thing that comes to mind on your year is an unbalanced driveshaft. There was a TSB on it a decade ago.

If you have the stock shaft, I'd bet money on it being the problem.

The tranny is easy to diagnose - At 85 mph, when it vibrates, put it in neutral. If it stops, it's in the tranny (but I don't think it is).

If it's not the flywheel (which if it was resurfaced it could be) it's the DS.

Also, no chance a weight fell off one of your wheels, right?
I have two driveshafts that have both been rebalanced by PST twice. Not the drive shafts.

Drive 85, clutch it or go to neutral = smooth as silk so that rules out DS or angles. I agree its the tranny and I believe its the 5/6 driven gear on the back of the mainshaft that has history of loosening up and causing my problem. Going to tackle that in the winter.
Old 07-20-2010, 12:53 PM
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exactly high mph trust me i just had this fixed it vibrates everything including ur transmission and shifter right and ur peddles , its ur flywheel its been cut to many times , its buttery smooth till u hit 75 and on its gets so rough u have to take the car out of gear, all that rubble isnt good for ur motor ,
Old 07-20-2010, 03:38 PM
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Originally Posted by alexcoreas
I had this problem. Did they resurface? Is ur clutch pressure plate smooth or is it a little bumpy? Did u balance ur pressure plate?
i do not know, i have only had the ride for a week, it is a 1997 z28. i looked at everything with it out of the car and nothing seems to be wrong, i put a straight edge on the flywheel and it seems level or staight or not warped. i do know the flywheel is not factory and the pressure plate is, not sure about the clutch.
Old 07-20-2010, 03:43 PM
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Originally Posted by JB_97ws6TA
lt1s are internally balanced in the front and externally balanced in the rear hence the weighted flywheel
so if i have it balanced would they balance it with or with out the weight, or is it even worth having one checked? thats kind of strange, the way they are ballanced, you would think it would play hell on the crank, but i guess that is why i am not a GM engineer.
Old 07-20-2010, 04:09 PM
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Just have them pull ur setup apart , check ur pressure plate , throwout bearing, and flywheel, I replaced my entire clutch, and it all went away my problem was my flywheel Was cut too many times
Old 07-20-2010, 04:19 PM
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Alex,
So if I understand you correctly, yours vibrated only above 75MPH regardless of gear. Correct?

Under 75, regardless of gear or RPM, it did NOT vibrate? Correct?

Did it vibrate at all sitting still and just revving the motor?
Old 07-20-2010, 05:22 PM
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Call me asap 8184330718 yea below 70 it would not vibrate whether it be in nutral 1,2,3,4,but if I started getting close to 65-etc it has a vibration big vibration. Call me it will take a min to explain
Old 07-20-2010, 08:05 PM
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We waNt to know as well
Old 07-20-2010, 08:15 PM
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Originally Posted by alexcoreas
Call me asap 8184330718 yea below 70 it would not vibrate whether it be in nutral 1,2,3,4....
If the car is stationary and you are getting no vibration while the engine is running during varied RPM the vibration is not coming from the flywheel.
Old 07-20-2010, 09:36 PM
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His doesn't vibrate because of high rpm or mph exceeding 70 its as soon as he puts it in 6th . He could go 110 in 5th no vibration, he puts It in 6th vibration. He could go 60 in 6th vibration occurs. Its his tranny its still stock and he's pushing 450rwhp and a 9in rear end. Stock trannys can't Handel all that and he also has 4.10s . Spoke to him on the phone and that is what we came up with. Really great guy
Old 07-20-2010, 09:48 PM
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Just to clarify, right at 400RWHP. Heavy vibes in 6th above 85, shift to 5th at 85 just a tad vibe, shift to 4th at 85 no vibe. I can drive 100 in 4th and there will be no vibe. No vibes in 1st through 4th regardless of RPM or speed.
Old 07-20-2010, 10:12 PM
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How much was the 9"

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