This build has been going on for quite a long time and I don't remember all the parts I have put into this engine/trans combo. I have a 1pc rms block (1991 truck 2 bolt). I purchased an Internally balanced Eagle rotating assembly crank rods pistons. Was balanced by cnc motorsports and my machinest. I used a Summit sfi neutral balanced Harmonic Balancer in the front. Now for the trans I bought a stage 3 clutch and lt1 steel flywheel. I'm pretty sure the lt1 FW is external balance. I seem to remember my machinest telling me that if he removed the weight on the FW it would be neutral balanced. So between my internally balanced rotating assembly, neutral balanced HB and supposedly neutral balanced FW( weight removed) everything should be balanced? I rebuilt the trans and had it running for awhile(last year in the driveway up and down the street in 1st and 2nd gear a couple times entire drivetrain has about 2hrs on it) and started to have clutch disengagement problems. Thought it was the slave. Replaced the slave, bled and stiil had the same problem with clutch disengagement. was screwing around pumping the clutch and all off a sudden I lost pressure in the clutch pedal. I had not secured the rod to the pedal so I assumed it slipped off. Shut the car down, looked under the dash and the rod was still attached to the pedal. put a clip on to secure and started the car again. Now clutch disengagement problems are GONE. Before this I could put the car in gear with the clutch in and stall the engine with the brakes. Now I have a bad drive train vibration feel it in neutral off idle. Gonna pull the starter and inspection plate tomorrow to take alook inside. Any suggestions? If the weight was removed to neutral balance the FW then I wouln't expect a weight to come off the FW to cause vibration. Possible pressure plate problem? I'm gonna call spec tomorrow and see what they say. Thing is that this build has been going on for years now so I don't remember if the FW is Spec or not. Thanks for reading any insight is appreciated. ATA I have an aluminum DS out of another 4th gen camaro/firebird.

 

Been doing alittle "searching" Seems all 86 and up 5.0/5.7 were "internally" balanced. Being that my stroker kit was "internally balanced", and I have a neutral balance Harmonic Balancer it seems that the FW/flexplate for the 1pc rms needed a weight for "external balance" because of the lip seal on a 1pc rms. So is it possible that my machinist knew this and left the weight on and it worked its way off? Ideas?

 

It's more likely that the pressure plate or disc suffered a failure than the weight worked it's way off. Starter/inspection plate removal to look-see is your next step. You may not see anything there and may need to pull the trans.

 

All Lt1 are internally balanced.

 

Yes all LT1's are "internally balanced" However, when GM went to a 1pc rms the internally balanced motor needed an externally balanced FW and a neutral balanced harmonic balancer, just like the LT1. From what I understand the only "externally balanced" engine is the 400. Also all(or most) engines from '86 and up 1pc rms engines are "internally balanced" neutral balanced HB and "externally balanced" FW.

 

All.
4.3L L99 V8
5.0L (various) V8
5.7L (various including LT1/4) V8

 

The TO bearing on the t-56 is held to the PP with a spring of some sort. Without this spring is it possible for the TO bearing to get behind the fingers of the PP and cause a problem or is this spring there to aide in the installation of the trans? Does the fork hold the TO bearing from going too far past the PP fingers into the clutch?

 

Once the trans is in the car the input shaft will hold the throwout bearing centered, and the clutch fork (and the tension of the hydraulics) should keep it from dropping into the clutch disc. I can see how it might rattle around and make nasty noises, but it shouldn't be able to interfere with the operation of the clutch. Either way, the clip is supposed to be there and I wouldn't put it together without one if I could help it.