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#1002190 - 05/10/14 04:44 AM T-56 flywheel question  
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zmans84ss Offline
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zmans84ss  Offline
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miami,fla
Hello everyone.
Recently got my car out of storage and working on it again after a long layoff.
Before I put it in storage I swapped in a t-56 out of a 95 tran am ( lt-1) engine is 350
Crate motor with one piece rear main seal. T-56 was rebuilt and I used new clutch and flywheel vehicle specific to the trans am. It has a very noticeable vibration and it just doesn't run correctly. Should I have had the flywheel balanced? I can feel the vibration on the floor directly in front of the drivers seat. Most of what I have read is about mating the t-56 is to a two piece rear main seal so I'm unsure how to pursue this issue. Any ideas would be greatly appreciated.

Thanks


1984 blue monte carlo ss,350 crate engine,LT1 t-56,Autometer custom shop gauges, GN 8.5 posi rear 3.42 gear,17x8 torque thrust wheels, 255/45/17 b.f.g. tires
#1002231 - 05/10/14 11:16 PM Re: T-56 flywheel question [Re: zmans84ss]  
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Onebadbowtie86 Offline
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Traverse City Michigan
Need to have the flywheel balanced the same as the flex plate that was on the engine.


'86 Monte carlo ss-Frame off resto-mod.
Ls2/t56/8.5"
#1002242 - 05/11/14 03:07 AM Re: T-56 flywheel question [Re: zmans84ss]  
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Jameson Offline
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Jameson  Offline
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Elizabeth City, NC
Was your engine internally or externally balanced when it was built? Did the flywheel that came off the engine have external balancing weights on it or not? Did the flywheel you installed have external mounted weights on it or is it zero balanced?


1988 Monte Carlo SS Eaton 112 5.3/T56 swap, Way to many mods to list.
2015 GMC Sierra Denali



#1002248 - 05/11/14 09:50 AM Re: T-56 flywheel question [Re: zmans84ss]  
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zmans84ss Offline
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zmans84ss  Offline
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miami,fla
I remember the flywheel had no weights at all. The flexplate is long gone and I don't remember if it had any weights. I think I should have balanced the flywheel and flexplate together but hind sight is always 20/20. Guess i am up the creek with out a paddle now!! Have no idea if the engine was externally or internally balanced. It's been in the car for about seven years now.


1984 blue monte carlo ss,350 crate engine,LT1 t-56,Autometer custom shop gauges, GN 8.5 posi rear 3.42 gear,17x8 torque thrust wheels, 255/45/17 b.f.g. tires
#1002255 - 05/11/14 12:28 PM Re: T-56 flywheel question [Re: zmans84ss]  
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Onebadbowtie86 Offline
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Onebadbowtie86  Offline
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Traverse City Michigan
Stock lt1's are externally balanced iirc. You should just have to take the flywheel to a machine shop and have it neutral balanced.


'86 Monte carlo ss-Frame off resto-mod.
Ls2/t56/8.5"
#1002271 - 05/11/14 03:23 PM Re: T-56 flywheel question [Re: zmans84ss]  
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zmans84ss Offline
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zmans84ss  Offline
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miami,fla
I thought since it had no weights that it was neutrally balanced. The engine is one piece rear main seal so it's 86 up block but not an lt-1. The thought of taking the transmission out all over again is not pleasant but I'm getting this right whatever it takes. Thanks everyone....


1984 blue monte carlo ss,350 crate engine,LT1 t-56,Autometer custom shop gauges, GN 8.5 posi rear 3.42 gear,17x8 torque thrust wheels, 255/45/17 b.f.g. tires
#1002279 - 05/11/14 04:58 PM Re: T-56 flywheel question [Re: zmans84ss]  
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rons87mcss Offline
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PA
Hmmmmm......
This definitely has me interested in what someone comes up with since I have always been under the impression that the stock LT1 flywheel would bolt right up/work just fine with an 86 and up 1 piece RMS gen 1 sbc think

#1002280 - 05/11/14 05:15 PM Re: T-56 flywheel question [Re: zmans84ss]  
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zmans84ss Offline
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zmans84ss  Offline
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miami,fla
I thought this was a simple bolt in as well since the expensive 2 piece rear main seal flywheel wasn't going to be needed. I'm thinking that I should have had the flywheel balanced so I suppose I could remove the flywheel and have it balanced but I want to solve the problem correctly. I would prefer a bolt in solution specific to this application but at this point I'm still debating how to pursue this issue. I accept that modifying the car will create these problems.


1984 blue monte carlo ss,350 crate engine,LT1 t-56,Autometer custom shop gauges, GN 8.5 posi rear 3.42 gear,17x8 torque thrust wheels, 255/45/17 b.f.g. tires
#1002290 - 05/11/14 08:41 PM Re: T-56 flywheel question [Re: zmans84ss]  
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Onebadbowtie86 Offline
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Traverse City Michigan
The flywheel does bolt up no problem, but some engines are internally balanced, and some externally balanced.

My 383 is internally balanced, so I had my stock lt1 flywheel neutral balanced.


'86 Monte carlo ss-Frame off resto-mod.
Ls2/t56/8.5"
#1002307 - 05/12/14 12:24 AM Re: T-56 flywheel question [Re: zmans84ss]  
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zmans84ss Offline
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zmans84ss  Offline
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miami,fla
So then the lt-1 flywheel I used that had no weights on it was not neutral balance as I thought? After countless hours in this the consensus is that most 1 piece rear main seal if not all are internally balanced but I have to continue the investigation. My next step to contact a few aftermarket flywheel dealers and get their information on this. I hope my situation alerts others as to avoid my mistakes.

Good luck all


1984 blue monte carlo ss,350 crate engine,LT1 t-56,Autometer custom shop gauges, GN 8.5 posi rear 3.42 gear,17x8 torque thrust wheels, 255/45/17 b.f.g. tires
#1002312 - 05/12/14 01:01 AM Re: T-56 flywheel question [Re: zmans84ss]  
Joined: Nov 2007
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Onebadbowtie86 Offline
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Onebadbowtie86  Offline
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Traverse City Michigan
I don't think they used weights on the flywheels, just drilled holes to lighten up parts to match. It sounds like you need to have the flywheel neutral balanced. What crate engine did you buy?


'86 Monte carlo ss-Frame off resto-mod.
Ls2/t56/8.5"
#1002314 - 05/12/14 01:15 AM Re: T-56 flywheel question [Re: zmans84ss]  
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zmans84ss Offline
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zmans84ss  Offline
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miami,fla
340 h.p. 350 crate engine from eBay vendor Phoenix musclecar. Crank is one piece rear main seal so I know the block is 86 up.


1984 blue monte carlo ss,350 crate engine,LT1 t-56,Autometer custom shop gauges, GN 8.5 posi rear 3.42 gear,17x8 torque thrust wheels, 255/45/17 b.f.g. tires
#1002332 - 05/12/14 07:35 AM Re: T-56 flywheel question [Re: zmans84ss]  
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Onebadbowtie86 Offline
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Onebadbowtie86  Offline
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Traverse City Michigan
Can you ask them what there engines typically are balanced?


'86 Monte carlo ss-Frame off resto-mod.
Ls2/t56/8.5"
#1002422 - 05/13/14 10:42 AM Re: T-56 flywheel question [Re: zmans84ss]  
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zmans84ss Offline
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miami,fla
I'm contacting the company to get that information. Depending on what they tell me I will decide what course of action I'm gonna take. Maybe replace the flywheel with aftermarket or simply balancing the flywheel I have now. Need more information before moving forward though.

Thanks again


1984 blue monte carlo ss,350 crate engine,LT1 t-56,Autometer custom shop gauges, GN 8.5 posi rear 3.42 gear,17x8 torque thrust wheels, 255/45/17 b.f.g. tires
#1002568 - 05/15/14 04:36 PM Re: T-56 flywheel question [Re: zmans84ss]  
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zmans84ss Offline
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zmans84ss  Offline
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miami,fla
As per the engine company my crate motor was internally balanced. I'm gonna have the the factory flywheel neutral balanced.


1984 blue monte carlo ss,350 crate engine,LT1 t-56,Autometer custom shop gauges, GN 8.5 posi rear 3.42 gear,17x8 torque thrust wheels, 255/45/17 b.f.g. tires
#1002582 - 05/15/14 09:24 PM Re: T-56 flywheel question [Re: zmans84ss]  
Joined: Nov 2007
Posts: 5,127
Onebadbowtie86 Offline
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Onebadbowtie86  Offline
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Traverse City Michigan
Good deal!


'86 Monte carlo ss-Frame off resto-mod.
Ls2/t56/8.5"

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