Any one had problems/solutions when installing a chevy lt-1 with a conventional late model truck flywheel and clutch. Mine is in front of an nv4500. I had the truck flywheel balanced to the original flywheel. Engine ran perfect before swap. All electronics are original except for every replaced tuneup items including the distributorless ignition. Both flywheels are one piece rear mains. Is it possible that the original clutch was not neutrally balanced. Any info will be greatly appreciated. Im so tired of lifting this tranny and 205. This is the only thing keeping my pig in the garage. Thanks for any help.
Balance issues with lt-1/nv4500 in 55
- Thread starter beer elephant
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Sounds like a GM question. Have you tryed the GM forum on Pirate?
- Thread starter
- #3
No, not pirate but nearly everything else including dealerships, this was my last hope. If no one answers I will try that, thanks
What is happening, basic vibration?
Since you had the flywheel match balanced to the old flywheel I'd say that's not your problem; unless the balancing shop made a mistake. With the LT1 I would guess it's more an ignition issue than mechanical problem. The Optispark distributor on the front of the motor is known to be a problem even if you install a new one right out of the box.
Look in the LT1 Tech forum at www.camaroz28.com lots of LT1 help to be found over there. Just tell'em you got a Camaro instead of a Toyota.
Good luck!
Nick Jennings
Look in the LT1 Tech forum at www.camaroz28.com lots of LT1 help to be found over there. Just tell'em you got a Camaro instead of a Toyota.
Good luck!
Nick Jennings
- Thread starter
- #6
To reply to whats happening, its a vibration just above idle that nearly goes away with higher rpm.
In the second reply concerning the optispark distributor, I did have it replaced. I don't know if this would show a code on a dealer's diagnostic equipment, but shows nothing on my simple tests. I appreciate the feedback any other is greatly appreciated and I will try the LT1 forum as well. Thanks again.
Andy
In the second reply concerning the optispark distributor, I did have it replaced. I don't know if this would show a code on a dealer's diagnostic equipment, but shows nothing on my simple tests. I appreciate the feedback any other is greatly appreciated and I will try the LT1 forum as well. Thanks again.
Andy
A bad Optispark will not throw a code most of the time. The symptom is usually a miss that could be anywhere in the rev range. Mechanically the LT1 is rock solid; most problems seem to crop up in the ignition system (Opti, coil, cap, rotors, wires and plugs) from what I saw watching the Camaro board.
I have one in my '96 Z28, 135K and counting, could use an ignition tune-up but still knocks down 20+ mpg. Even when I lay into the silly pedal...which is often! I've done little more than regular service to the motor - oil and filter changes per the owners manual for the most part. Water pump has been the only major repair issue with the motor... bought the car new and it still puts a chit-eatin' grin on my face after I run it through a few gears! 
Nick Jennings
I have one in my '96 Z28, 135K and counting, could use an ignition tune-up but still knocks down 20+ mpg. Even when I lay into the silly pedal...which is often!
I've done little more than regular service to the motor - oil and filter changes per the owners manual for the most part. Water pump has been the only major repair issue with the motor... bought the car new and it still puts a chit-eatin' grin on my face after I run it through a few gears! Nick Jennings
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- #8
I had silly ideas of miles per gallon and horsepower when I chose this combination. I dont think I will be disappointed when I get this figured out. I am dieing to see how this spring over reacts to the trail. Any ways I have a friend who had a 93 Trans Am w/ LT1. His opti went bad, it would jerk severly and intermittently. The moter I purchased has 40 K on it. It ran perfect in the car before swapping. Could it possibly be the Pilot bushing? I replaced w/ a new bronze one from GM. I never checked the tolerance.
Thanks Andy.
Thanks Andy.
you do have the firing order correct / leads on the right spots dont you?
and the harmonic balancer is tight, and not rotated?
and what type of engine fan does it have?
and the harmonic balancer is tight, and not rotated?
and what type of engine fan does it have?
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- #10
I did check the plug leads, everything good there. If the balancer was removed it was done by the dealer before the swap, I really doubt it has been taken off. I was able to fabricate brackets and use the original fans. Fits very nicely in a 55. The engine is completly original except for the throttle cable,starter,flywheel and pilot bushing, rear main seal. All ignition components were replaced, plugs, wires etc. The motor was taken well care of by previous owner. I have tried every electronic approach to the problem I know or have researched. All the wiring harness is original. Could a vehichle speed sensor affect idling in the garage cause I dont have one. The problem appears to be related to either the balance of the flywheel/clutch/pilot or alignment but what do I know I dont care to mention how long Ive been working on this problem.
Thanks again Andy
Thanks again Andy
orangefj45
Supporting Vendor
i would definetly suspect the flywheel. buy another flywheel for that year engine application. do not go by what trans you have behind it. all clutches are neutral balance.
would it be possible for you to remove the tranny and start the motor wo any tranny components attached. you could narrow the location of the vib down easily that way. Either its part of engine ops or its not then. What about compression numbers, do you have good compression in all the cylinders, i recently had a 2f in my shop with a failed head gasket bn 3 and 4 (they exchanged gases) it vibrated badly at idle and lessened when throttle was applied. Just a thought
orangefj45 said:
orangefj45 - With an LT1 from a Camaro/Firebird/Vette this doesn't quite work. The LT1 uses a flywheel/clutch combo specific to the 6-sp that came with the cars. That clutch is not even close to what the NV4500 uses which is why you have to use a flywheel/clutch from a different application. Just one of the quirks you have to work with when using an LT1; it's not quite as easy as the standard SBC conversion...
Nick Jennings
- Thread starter
- #14
Thanks for all the suggestions, the previous thread is true concerning the clutch, most definitely different and with a fery light flywheel. Anyways, dropping the trans is the only way to isolate the issues as suggested above. I felt that asking on this forum might limit the possibilities without touching the truck again. This has done that for me. Thanks again for the input this is very encouraging. Time to go bench press the trans and do some wrenching. Andy
orangefj45
Supporting Vendor
i realize that the LT1 clutch setup is different, we sell them at work. the factory units come rivited together, so you have to get a clutch and flywheel combo set, AFAIK.
what flywheel are you running?
what flywheel are you running?
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- #16
Using a 94 model GM truck flywheel and pressure plate and disk. All original complete package from GM. I chose the 94 due to the engine block being a 94. I was told that both engines were externally balanced through the flywheel. According to the balancing shop they were off slightly.
LT1's like to run rough off of idle when the headgaskets go south too....just a thought
