[mgarblik]

Following this thread. It seems like you may have a couple things going on here. Problem 1 is the vibration you describe. Problem 2 is the clutch chatter. IMO, you may need to divide and conquer. A quick and easy might be to install the rubber trans mount and see what that does. It may help/eliminate the vibration but I doubt it does anything for the chatter. Make sure absolutely NOTHING is contacting the body structure at ride height with everything installed. This would include ANYTHING in the exhaust system touching anywhere, the bellhousing touching the trans tunnel, the shift tower touching the tunnel, just anything. This can transfer the slightest vibration through the body structure and drive you crazy at any engine speed.
If you just can't find anything, then the assembly will need to come apart. I would remove the trans, clutch and PP. Support the oil pan with a floor jack and a couple bath towels and run the engine with just that weighted flywheel. See if it is smooth without any vibration. If smooth, move on. If a vibration is felt, remove the weight and try again. If a vibration is still there, install the OE flywheel and retest. It should be smooth now. If vibration is still there, now engine mounts are about the only thing left.

Moving on to clutch chatter. Look at the clutch disc and see what you have. For street use, you really need a disc with torsional vibration springs in the hub.. If a solid hub, not ideal for street use. They always chatter. The disc itself should have marcel wafer springs between the facings. It they are flat steel, no marcels, again not ideal for street use. The dual facings, ceramic and organic do tend to chatter a little. I run my 500 HP engine in a 4000 lb. + Catalina with a plain old LUK organic disc and a diaphragm PP. No issues at all and very smooth engagement. Hope these ideas help you nail this down so you can enjoy your ride.

[scott70]

Originally Posted by chuckies76ta

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.

Im on the lookout for a rubber mount thats at the correct thickness. I ordered a new speedo gear from silversport ,,,,18 tooth instead of 17,,,,and tremec fluid for the change from dextron 3. I asked about the rubber one they sell but its too tall at 2" thick, the flywheel bolts are the originals and dont hit anything. The instructions say to give it some break in time so we'll see how the chatter goes. Yes ideally trying to match the imbalance of the oem flywheel and the new billet is not what you want. Im not a machinist/mechanic and dont know what acceptable. The engine shop knows the flywheel only goes on one way and Im assuming they know what theyre doing. Id love to pull the motor and maybe a different clutch and have the whole thing rebalanced but that sounds drastic at the moment. I can notice the vibration but its slight. The chatter is actually more annoying at the moment. The clutch disc does have the damper springs.

[AG]

Your clutch has a sprung hub and Marcel carrier which is good. The disc is organic on one side and ceramic on the other which makes it a little grabby, hopefully that goes away when it breaks in.

[jhein]

Sorry if I missed it but which Mcleod kit do you have? Just asking because I may have the same one. From your OP, it sounds like you're saying the vibration is constant frequency regardless of engine RPM. Is that correct? If so it seems like that's not likely to be from anything that's rotating.

[scott70]

Originally Posted by jhein

Sorry if I missed it but which Mcleod kit do you have? Just asking because I may have the same one. From your OP, it sounds like you're saying the vibration is constant frequency regardless of engine RPM. Is that correct? If so it seems like that's not likely to be from anything that's rotating.

It’s the super street pro… organic on one side ceramic on the other. Yes the first time I fired it up I could feel a slight vibration compared to before… even at idle it’s not the same.I’ve had it to 5500 rpm’s and 90 mph and it didn’t get worse. Actually at that rpm and speed it’s hard to notice anything… lol but yes it’s constant. I am going to crawl around underneath and make sure the trans isn’t touching anywhere or the exhaust. This is the trans mount I’m using. This mount is the same height as original and says softer uerathane for more forgiveness I guess. I noticed some mounts are closer to 2” thick. That’s too tall for my situation.
Other than that I like the trans so far…shifting feels smooth and feels like I should be able to shift it as quick as the Muncie/ hurst that was in it. I’ll try it at the track next summer. Hopefully the clutch comes around and I don’t have to replace it. McLeod says in their paperwork that clutch chatter is not warranted.

[chuckies76ta]

Was just thinking that you said you have the tranny up against the floor. That will surly cause some vibration. Check these guys out see if they have anything. https://www.steelerubber.com/steele-...d_WzO4xHlk-MxY

[scott70]

Originally Posted by chuckies76ta

Was just thinking that you said you have the tranny up against the floor. That will surly cause some vibration. Check these guys out see if they have anything. https://www.steelerubber.com/steele-...d_WzO4xHlk-MxY

It’s close but I don’t think the trans is touching the floor boards but I’m going to double check this weekend. The temps are dropping and will get to the point things will have to wait till next spring. My ambition goes away with a cold cement floor and a salamander heater…. Lol

[Scarebird]

Originally Posted by scott70

...and tremec fluid for the change from dextron 3...

I used Redline for excellent results vs GM manual trans fluid.

[jhein]

Originally Posted by scott70

It’s the super street pro… .

Mine is the "street extreme". ceramic/ceramic. I have had a little chatter but nothing bad or consistent.

[AG]

Originally Posted by Scarebird

I used Redline for excellent results vs GM manual trans fluid.

Wow, moved to Portugal?

[Scarebird]

Yes, late this Summer. My 71 according to the shipping guys is off Gibraltar currently. Getting it registered here will be a proper donnybrook.

mgarblik has the right idea here - I would get after it regardless of cold while memory is still fresh.

[scott70]

Originally Posted by jhein

Mine is the "street extreme". ceramic/ceramic. I have had a little chatter but nothing bad or consistent.

Was it worse in the beginning or has it been pretty consistent over the miles?

[jhein]

Originally Posted by scott70

Was it worse in the beginning or has it been pretty consistent over the miles?

Consistent. But, it's mild. I don't consider it a problem, but it gets a little grabby sometimes from dead stop. I think that's normal? No vibrations at all at idle or at speed. Really smooth at speed actually. Of course, the assembly was balanced by my machinist/builder. I don't know what, if anything, he had to do to balance the assembly so I can't help you there.

[scott70]

Ive wondered how that worked. If a oem pontiac flywheel is not neutral balanced and if back in the day a flywheel had to be replaced under warranty the replacement FW must have the same imbalance? Were all pontiac flywheels back the balanced the same? So you could replace them without throwing things out of wack? I read in the thread tale of 2 flywheels where it was recommended to balance a motor where you can use neutral balanced things like a flywheel. Makes sense.

[AG]

Originally Posted by scott70

Ive wondered how that worked. If a oem pontiac flywheel is not neutral balanced and if back in the day a flywheel had to be replaced under warranty the replacement FW must have the same imbalance?
Yes

Were all pontiac flywheels back the balanced the same?
Yes

So you could replace them without throwing things out of wack?
Yes

I read in the thread tale of 2 flywheels where it was recommended to balance a motor where you can use neutral balanced things like a flywheel. Makes sense.

It's always better to neutral balance the rotating assembly and flywheel/clutch separately in case you need to change anything it's easy. The factory imbalance was small, about 10 in-oz and it's easy to neutral balance a rotating assembly, doesn't need any Mallory metal.

[scott70]

Originally Posted by AG

It's always better to neutral balance the rotating assembly and flywheel/clutch separately in case you need to change anything it's easy. The factory imbalance was small, about 10 in-oz and it's easy to neutral balance a rotating assembly, doesn't need any Mallory metal.

I wish I had known that back when my motor was rebuilt,,,I would of asked for that. Someone said looking at the OEM flywheel I removed that mine must of been balanced like the factory did it.

[scott70]

So I checked where the trans is close to the floorboard,,, it’s not hitting. I removed my trans mount from the Muncie and was going to swap it with the poly one. The poly that’s currently in the car is softer than the old rubber one so I left the poly in it. If you push your finger into it the poly is definitely more pliable. I removed the starter to look at the weight. Should I take it off and run it without it? The oem flywheel is not neutral balanced so I’m assuming if I take the weight off it won’t like it.

I went for another ride prior to this and would change my description from a vibration to a very small shake. I think that’s more accurate. When you have it idling it feels like more of a shake compared to before I switched the transmission. Been also trying to drive the back roads trying to get more shifts in ( break in) to maybe see the chatter lighten up. Nothing yet. If you take off slow and just let the clutch out fast you don’t notice it really but if you ride it at all it will start to chatter about half way to full clutch engagement .

[Scarebird]

I would remove the weight and see what happens.

[mgarblik]

Originally Posted by Scarebird

I would remove the weight and see what happens.

I think this is an excellent approach. It won't hurt anything. If your lucky, it will get either worse or better and not stay the same. That weight is so far from the crankshaft centerline, it will have a huge effect on engine balance. Just a guess, But I bet it's way too much weight. If that weight is made of steel, you could make a duplicate one out of aluminum and bolt it on and see what it does. There will be some guessing moving forward vs major disassembly to properly balance it. But it can be done.

[AG]

Originally Posted by Scarebird

I would remove the weight and see what happens.

I agree, take it off and see what happens. That weight looks like it is more than the factory imbalance, but that doesn't mean anything. Take a look at your stock flywheel and you will see the holes drilled for the factory imbalance, it doesn't look like much. If you have an automatic flywheel you'll see it also.