Hi fellow F-Body owners. I have a 97 LT1 w/383 and need help with my install of a SPEC stage 2+ and flywheel. The clutch came with an alignment tool and the tool had a bearing (maybe pilot bearing) on it and I was wondering if this bearing is to be installed behind the flywheel?

Why do I ask? Because I did this and I have a monster vibration after installing the aluminum flywheel and clutch. Turned that car on for a few seconds and knew something was wrong.

Are we supposed to be using this bearing that came with the alignment tool? I am thinking not but what have you all used?

Thanks for your help, this is my first clutch.

 

Hi Everyone, I am thinking that I should provide some more information. The clutch that was in the car was a mcleod clutch and when I took it out, it did not have a pilot bearing (behind the flywheel). Did I mess up by putting one in that came with the spec clutch?

Should I remove it?

Thank you for any response. I am kinda stuck.

 

The pilot bearing is critical. This keep the nose of the input shaft centered So the pilot bearing needs to be replaced every time you change the clutch. I took mine out and noticed it was oblong instead of round on the inside. Also with a aluminum flywheel, following torque is critical also

hth

andy schuck

 

Two things, there must be a pilot bearing present and did you have the flywheel balanced?

I think the vibration is from the flywheel itself and not the bearing.

 

The aluminum flywheel is new from Spec, Do I need to have it balanced. I thought it would come balanced from them.

I torqued the flywheel to 55lbs based on other forum posts that I have read. the clutch or flywheel did not come with any instructions. I have also read 22lbs for the flywheel. Do you know which one is right?

 

The "How to Rebuild the LT1" book indicates 74 ft-lb for flywheel or flex plate bolts. Chiltons says the same thing.

 

Thank you Injuneer. Sounds like I will tear it apart again today and torque flywheel to 74 lbs.

Thanks bh_hunter, I thought it needed to be there but was thrown for a loop with the old clutch assembly not having one.

 

The alignment tool won't hold the clutch plate in the proper place without the pilot bearing or pilot bushing. The input shaft and bearings in the transmission won't last long without it in place.

 

Thank you Procharged94LT1, This is probably why my clutch only lasted 2k miles. I am taking it apart now and will torque the bearing to 74 lbs. I might also replace the pilot bearing with a new one at the same time.

Hopefully this will help. I hope the dealership has this bearing in stock.

 

You would torque the flywheel bolts to 74 ft-lb. The pilot bearing just presses in.

 

ok - took it a part and torqued the flywheel to 74 lbs. The dealerships were not open so I did not replace the pilot bearing. I put it back together and the vibration is still there.

I did drive it around the block and the clutch engages and disengages nicely. The vibration is less after about 1500 rpms and returns around 4000 rpm.

Am I being paranoid in thinking that going from a stock flywheel to aluminum flywheel that the car should act the same? The aluminum is a lot lighter (almost 20 lbs).

Could this lighter flywheel have this affect? If so, is this normal or will it get better as things get broken in?

I did put about 10 miles on it and it drives fine, gets rpms very fast, but with the vibration.

Am I right in thinking that if the flywheel was not properly balanced or installed correctly that the vibration would get worse with more rpms?

Thanks for all of everyones help. I guess this is what I get for wanting to work on it myself.

 

How do I tell if my motor is internally or externally balanced? Can I tell by looking at the old flywheel? It does not have any weights on it. The new aluminum spec flywheel did have weights on it.

Should I remove them?

Did I install the wrong flywheel?

 

The stock engine was externally balanced, and the flywheel had a weight on it to balance the engine. If they took the weight off the flywheel (or installed a new flywheel without the balance weight) its likely the rebuilt 383 is internally balanced. Do you have access to the builder of the engine?

If you had no vibrations with the steel flywheel, I would take it to a shop and see if it is neutral balanced. If it is, you will have to pull the aluminum flywheel and have it neutral balanced.

 

Thank you Injuneer for all your help and advice. The motor was built and installed by Combination Motorsports in Las Vegas and they are now out of business so I think I am on my own.

Your suggestion makes sense. I will take the original flywheel to a machine shop and see what they say. I might as well have them resurface it as well so that it is ready if I need to swap it out.

Sorry for all the remedial questions and I appreciate your and others responses.

Wish me luck tomorrow.

Thanks again.

 

Injuneer, I think is is figured out. The flywheel that was removed was neutral balanced and the one I installed was externally balanced. This was confirmed by taking the flywheel I removed to a local machine shop confirming it was neutral and a call to Spec this morning telling me that the new flywheel was externally balanced.

Spec said to make the new flywheel internally balanced I need to remove the three screws holding the weight, the weight, and then reinsert the middle screw.

I will post with my result. Thank you again.