vibration

Hope everyone had a good holiday!! Now on to my question...I installed a T-56 about a month ago in my IROC-Z. Now I have a vibration at a about 2300 RPM and up. The trans has been rebuilt as well. The vibration can be felt at a stand still while revving the engine. I put the trans in gear and depress the clutch and can feel it. I installed a new GM LT-1 flywheel, and SLP's disc and pressure plate, and new Moroso pilot bearing. Has anyone had a problem with the GM Flywheel before on a swap?? or SLP's clutch set???
Chris

How is your tranny mount?

It is a new Poly mount, W/ Spohn Tourqe arm and crossmember. Poly ends

I have herd of that problem it has somthing to do with the ajustment on the clutch it might be sort of ingaged or the fly wheel could have a slight worp hope u find the problem it sounds lick its ticking u of good luck:confused: :confused:

My auto uses the same mount as you, I believe. When I installed it, I felt a lot more vibration.

i dunno the only thing that happend when my tranny mount went was when i accelerated the car jolted forward just a bit and made a thump noise.

Thanks for the replies!!! It feels more like a vibration from the Flywheel than anything?? The mount I do not see causing this much problems.

anyone else have any ideas??

Just a thought. How is the driveshaft? Has it been balanced and have you checked that the U-joints are not notchy?

The vibration can be felt sitting still. Wheels do not have to spin at all. But yes the driveshaft is OK it is a new 1LE piece.
Chris

I thought the flywheel was supposed to be machined flat when a new clutch is put in. Did you do this?

Was a new GM LT1 flywheel, New SLP pressure plate, new SLP clutch disc, New Moroso pilot bearing, New GM bolts with Loctite through out, and torqued to spec.

Ok, this may be reaching a bit, but check out this thread

http://www.thirdgen.org/techbb2/showthread.php?s=&threadid=153898&highlight=vibration

This was for an auto but it may apply.

Good thought but I just had the trans. out looking at the clutch set and all my bolts were tight. Used Loctite on them as well!
Chris

Thanks for the replies:bow: :bow:

I might be mistaken but you should get new flywheels reserfaced also.

My flywheel came with the pretty half moon machining marks on, why should I have it done again?
Chris

Don't the flywheels have balance weights on them like a wheel or a driveshaft. Did you notice if there where any weld spots that where missing the wieghts.

I honestly did not look for weights at all. I figured that since the LT1 & L98 were internal balance then bolting on the LT1 flywheel should be a no brainer. I thought. :(

The weights on the flywheel is just another long shot. But it seams like they where on there last time mine was out. I'm pretty sure torque converters and flex plates have them also. Flywheels are pretty heavy so you would think they had to be balanced. But I would look for a much more reliable source than me before disassembling.

I agree with you, it has to be a flywheel balance problem. You said with the cluth depressed and engine revved you get the vibration. The only thing spinning is the engine/flywheel and trans input shaft. The LT-1 flywheel has balance weights on it. If you replace the flywheel in an LT-1 you need to put the weights from the original flywheel into the same locations on the new flywheel. If you did a swap like you did, you need the flywheel balanced to the engine. The only way I know how to do this is with a strobe balancer. The GM dealer can do this with a tool called the EVA (electronic vibration analyzer). It's not easy to do but possible. You can also check with trans. shops or maybe a driveshaft specialty shop, they may be equipped to do this. A reputable machine shop may also help. GM never recommends machining a flywheel. It can cause clutch disengagement problems because the pressure plate becomes further away from the fork or concentric slave. Depending on the set-up the trans has. Hope this helps.

Thanks for the input. I have heard that from some people around here as well. I actually have gotten fed up with it and have ordered a McLeod 0 balance flywheel and clutch assembly. Also while in neutral with it revving I had in gear as to eliminate the input shaft bearings.