[scott70]

Ughh,, I just wrote out a whole thing and then wouldn’t post it ,, now gone. Now a quick version,,, installed new trans, McLeod flywheel and clutch kit. First start up I noticed a slight vibration that hadn’t been there before. Tried different rpms to see if it would increase but the vibration was consistent. Clutch in or out. Went for a drive,, tried rpms to 5500, tried up to 90 mph. Vibration didn’t increase. Vibration is slight,, driving it there’s times it’s hard to notice but my son could also feel it on the passenger side. Since the vibration can be felt sitting still it seems it’s not in the trans and back.The new fw was checked at the machine shop prior to installation. They added a bolt in weight to the fw and had to index the PP to get it to match the imbalance of the oem flywheel.
I like the 2.87 first gear compared to the original m21 2.20 gear ,, it’s not radically different though and I like the .81 od,,, seems perfect for me. I guess the vibration isn’t so bad as I’d pull stuff apart but I can notice it and me being me it’s annoying. I do have the clutch chatter taking off, especially on a slight incline. Hopefully that goes away.
Old and new flywheels.

[mysticmissle]

Is the motor internally balanced? If so I think you are supposed to loose that bolt on weight
Probably so it then the access hole w some effort

[scott70]

Originally Posted by mysticmissle

Is the motor internally balanced? If so I think you are supposed to loose that bolt on weight
Probably so it then the access hole w some effort

The motor was balanced with the oem flywheel years ago but the machine shop didn’t have the information or balance card on it. They spun the oem and tried to match the new one to that. Someone said looking at the oem it isn’t neutral balanced like the new McLeod fw is. The McLeod pp was supposed to come factory neutral balanced but when checked it wasn’t so by adding the weight and indexing the pp to a certain position it came out the same as the oem flywheel on the balance machine. I’m just relaying what they said,, I’m not a machinist.
That particular weight came with the new flywheel for certain applications.

[Formulas]

examine the new flywheel in every aspect you can..

i had a OE that was not faced correctly giving the clutch a slight bit of wobble working on the input shaft.... hard to pin down or notice prior.... i took it in for a turn as regular maintenance stood and watched the guy set it up and start machining it the face had about .030 runout

[Singleton]

Originally Posted by Formulas

examine the new flywheel in every aspect you can..

i had a OE that was not faced correctly giving the clutch a slight bit of wobble working on the input shaft.... hard to pin down or notice prior.... i took it in for a turn as regular maintenance stood and watched the guy set it up and start machining it the face had about .030 runout

Same thing happened to me when I bought a brand new Hays Flywheel several years ago. It was not machined flat from the factory. Like you, I found this out after having it resurfaced by a local shop. I don't know the amount of runout, but the shop said it was real bad. The end user is now the Quality Control...

[scott70]

I had them take just a whisker off the FW face to make sure that surface was true and the clutch side had the right surface roughness. Wouldnt that have trued things up? I tried to think of everything I could so I would minimize any chance of a out of balance vibration. A energy suspension trans mount came with the silver sport trans. It was a revised model I guess that was the same hegiht as the factory and supposed to be a " softer" urethane.

[jhein]

I've been looking forward to your review. Sucks to hear about the vibration. I'm glad you like the gearing. Hopefully you can get the vibration figured out.

[JLMounce]

You mentioned that the flywheel was checked. was the pressure plate checked as well? There's a few machinists that I follow on social channels, and it's unfortunately somewhat common for pressure plates to be out of balance.

If you put in the new trans, you likely also installed a new trans mount. If you are using rubber mounts in the engine and a poly mount in the transmission, this can in some cases also cause vibration to be felt through the cabin. Changing to a stock type rubber mount may help.

[West Coast GTO]

Don't know if this will help with your application but, when I was into Corvettes, I installed a McLeod clutch/ pressure plate that was factory balanced. Vibration consistent in all rpm ranges. Had the assembly( clutch/ pressure plate/ flywheel) balanced as a unit and no vibration.
Hope this helps.

[Gator67]

I bought a McLeod pressure plate last year and asked my machinist to check it out. Lucky I did, for it was 58 grams off! They sent me a replacement, which was a lot closer, but it still needed balancing.

[chuckies76ta]

If you are using rubber mounts in the engine and a poly mount in the transmission, this can in some cases also cause vibration to be felt through the cabin. Changing to a stock type rubber mount may help.

This ^^^. Get rid of that polymount. Use the rubber one. Which McLeod clutch did you go with and which disc?

[scott70]

I used the 11” super street pro clutch kit. The machine shop said the pressure plate was not balanced very well but were able to put the pp on the flywheel and get it to the same imbalance as the oem flywheel. Took it for another ride this afternoon. The vibration isn’t horrible… doesn’t vibrate the rear view mirror or anything but it’s not like it used to be. I guess it could be the trans mount. Would a flywheel imbalance vibrate more with rpm? Clutch chatter was pretty bad ,,, probably worse than any other new clutch I’ve ever had. But the clutch disc is organic on one side and pucs on the other where all my other clutches were full organic.

[64speed]

Pinion angle was the sources of my TKO install post vibration.

[ID67goat]

I was curious if the bell housing was indexed during the install? These new modern transmissions need much more precision alignment than the old 3/4 speeds.

[tom s]

I had one disk with the pucks.ONE!Never again for a street car.Tom

[scott70]

Originally Posted by 64speed

Pinion angle was the sources of my TKO install post vibration.

Mine does it sitting still.

[scott70]

Originally Posted by ID67goat

I was curious if the bell housing was indexed during the install? These new modern transmissions need much more precision alignment than the old 3/4 speeds.

I had to use .007 offset dowels and got it almost perfect with the dial indicator

[scott70]

Originally Posted by tom s

I had one disk with the pucks.ONE!Never again for a street car.Tom

yup,,organic on one side ceramic on the other. Bad chatter taking off right now.
I’d be willing to try an oem rubber style trans mount but it needs to be no more than 1 5/8” total height. That’s what my old one was and that’s what this particular poly one is ,, I guess their other mounts were tall so they made this shorter one for the older A body’s. Can’t find measurements on the rubber ones. The tkx is close to my floor boards and can’t go any higher.

[64speed]

Originally Posted by scott70

Mine does it sitting still.

I read that and totally spaced anyway. Sorry!

[chuckies76ta]

Originally Posted by scott70

I used the 11” super street pro clutch kit. The machine shop said the pressure plate was not balanced very well but were able to put the pp on the flywheel and get it to the same imbalance as the oem flywheel. Took it for another ride this afternoon. The vibration isn’t horrible… doesn’t vibrate the rear view mirror or anything but it’s not like it used to be. I guess it could be the trans mount. Would a flywheel imbalance vibrate more with rpm? Clutch chatter was pretty bad ,,, probably worse than any other new clutch I’ve ever had. But the clutch disc is organic on one side and pucs on the other where all my other clutches were full organic.

It's had to say if a flywheel out of balance would vibrate more or not. I would think it would, but at certain rpms it might go away.



I also would go full organic disc clutch for street use.



Try the rubber mount on the tranny cross member. Shouldn't be hard to find one. I guess you could also have the pinion angle checked.



I'm not liking what is going on with your old flywheel and pressure plate in relation to the new stuff. Our engine are normally built internally balanced. So your taking a neutral balanced flywheel and adding weight to try match to your engine that was balanced eternally. So you got the F/W and P/P balanced together, but how is that suppose to index on the Crank? Flywheel only mounts in a certain spot on the crank. I'm thinking start from scratch and use your old F/W and P/P and see if you vibration is gone.

I think I would then try the new F/W without the weight on it which puts it back to neutral balance and install new clutch kit see how it is.



Something else you may need to check is the height of the flywheel bolts to the crank. I've as others have had the ARP Pontiac bolt heads interfere with the clutch disc.



Just throwing some thoughts out there. Not a mechanic here.