Jesse Lackman

I searched here but couldn't find posts that describe the clutch problem I have. As far as I know it is stock with about 70,000 miles on it.

It does not slip/chatter/buzz except during a partial thottle start in first gear. When it does this the only solution is to push the clutch in and start over.

Doesn't do it on a light throttle start.

Only does it in first gear.

I would call the noise a buzz, is this what people call "chatter"?

There is no problem doing a first gear burnout when you aggressively engage the clutch, that is why the partial throttle slip, buzz, chatter, or whatever it is called is so weird.

There doesn't seem to be any vibration in the clutch or drivetrain, I have never seen a clutch act this way.

Why is the clutch doing that? Is it a common problem?

Thanks,

Jesse

Jesse Lackman

Well I know now what the chatter was. It got worse with heat and was so bad one hot day I though it was going to wreck something. The flywheel and pressure plate appear to have wiped metal into high spots in three places on each. That seems to have caused the center hub of the disk to wind up and unwind on the disk hub springs so much it banged against the stops in both directions. That is about an inch of movement at the disk hub diameter. I can post some pictures later. The pilot bushing was hammered out about .125 larger than new.

I'm about done installing an new Street Twin, aluminum flywheel, Tick master cylinder, Mcleod slave, new GM pilot bushing. The Twin Disk disks are one piece, they do not have the center hubs and springs, good! It's got a new Pro 5.0 and UMI short stick. It takes both hands to get it into reverse with that UMI, my wife doesn't like that and the car isn't even running yet. Might have to put the Pro 5.0 handle back on.

BTW if any need a stock genuine fluted GM 10125896 pilot bushing there are two at Sax Motors in Boman ND.

Jesse Lackman

Well they say the best things in life aren't easy;

http://forum.mcleodracing.com/showth...T1-Street-Twin

Getsome17

[QUOTE=Jesse Lackman;6468919] It's got a new Pro 5.0 and UMI short stick. It takes both hands to get it into reverse with that UMI, my wife doesn't like that and the car isn't even running yet. Might have to put the Pro 5.0 handle back on. [QUOTE]

I think reverse is blocked out when the car is shut off, the same as how it blockes it out when the car is moving.

Jesse Lackman

You're right.

I got the new ring gear on and while I had it all apart again I removed around .132 from the clutch fork pivot which moved the clutch fork away from the pressure plate enough for .500 travel of the throwout bearing without the fork hitting the pressure plate. Even with more travel there is no way the clutch fork will ever again hit the pressure place because the throwout bearing will hit the front of the transmission first.

Details are on the mcleod forum link.

Getsome17

The exact same thing happened to me after I got my street twin rebuilt last year I went to fire it up and bag 2 teeth gone off of the ring gear. It sucks having to pull everything apart just to get at it. I did the same thing you did to fix it and it works great now. But it would have been nice to have some warning or a way to check it before starting the car back up.

Jesse Lackman

The next thing that went bang (last Thursday) was the LS1 aluminum driveshaft I had new U-joints put in and balanced.

I'm having the shop build a 3" .083 wall steel driveshaft with solid u-joints since I read about stock steel driveshafts twisting in two.

The LS1 aluminum was 3" dia .065 wall!!

Kinda torques me because I had $300 in that LS1 shaft, I'd have went new if I had any idea they were so weak.

Jesse Lackman

Mike what clutch master cylinder are you using?

The clutch is working good, seemed a little grabby or jerky at first but is smoothing out. The Tick master supposedly has a 7/8" bore as opposed to less for the Mcleod master. McLeod said the Tick setup would run at a 1:1 ratio making the pedal harder to push and requiring less pedal travel. Tick recommends adjusting the pedal to minimum and increasing until there's clean clutch disengagement. The pedal is supposed to hit the floor before the clutch fork hits the pressure plate bolts. (If you read the Mcleod forum link you will see ours had .360 travel to hitting pressure plate bolts which equaled .270 clutch release - not enough in my opinion as Mcleod recommends .500 throwout bearing travel for clean release.) Anyway the pedal sits much lower than stock, it has to be reporgrammed in your brain. We've killed the engine a few times because the pedal height is so different.

I suppose the whole setup could be set up to reach .500 disengagement right when the throwout bearing hits the front of the transmission, and at a normal clutch pedal height, not sure what the pivot height would have to be. It would vary depending on the clutch master and slave cylinder diameters.

The Tick master uses a Tilton cylinder, I'd guess a smaller diameter cylinder could be bolted on the Tick mount for an "underdrive" ratio and more pedal travel in relation to slave cylinder travel. That would be a better setup in my opinion, would in theory slow down shifts but would feel more like stock, something my wife would like. I try to tell her these cars are vanity cars, they're like young stallions, they're tempermental, not like Buick Park Avenues. If she's feeling like an old grandma and wants to drive an old plug, take the Buick.