Competition Clutch; Severe Grind and Shudder

[Big MAK]

I'm begining to think it's been installed wrong or something severe is broke. It sounds like something's getting ground up whenever the clutch is at the engagement point. Metal on metal grind-grind-thunk-thunk; then a couple lurches and it's engaged. Once engaged; seems 100% ok. When fully released; seems 100% ok. But at take off; it's like the transmission and drivetrain are falling out. Also makes a nasty grinding noise and vibration if downshift while driving. At take off; shakes the truck enough I looked to make sure the driveshaft wasn't coming off.



SBC DD 12CB, already upgraded slave and master cylinders.

 

[jwilliams3]

Mak,

You FRIED it.



What has probably happend... ...

You have melted pieces of the ceramic pucks onto the flywheel(s) during slippage.

These weld spots where clutch material has built up is causing the violent shake during engagment.

Call Peter in the morning.



Sorry to hear about this.

Have you pulled or raced lately?



Your power you need the 3850lb FE/CB or FE/FE.

Good time to upgrade flywheels too

 

[Big MAK]

A little street racing, it's not more then the clutch is rated for so I'm surprised. Will going from 3600lb to 3850lb make that much of a difference?



Also; this will still be a street driven truck. I couldn't care less about pedal pressure so I don't mind that. Will a 3850lb hold up OK daily driven? I suppose it's a good thing the hydraulics are upgraded.



Definitely calling Peter in the morning; these things always happen on weekends!

 

[jwilliams3]

3850lb is ok for street driving (I say this as my knee aches!).

Go ahead and get both FE disks.



Daily driven you shouldn't have an reliability issues.

It seems slippage is what causes the failures.

Even after I fried my first one, the clutch on the street would not slip (or at least I could'nt feel it).

 

[Fred Swanson]

Mark, how many miles on that clutch? I've had no hint of slippage with mine.

 

[Big MAK]

Only about 1000 miles. I'm wondering if the plates were alligned properly when installed. I kind of suspect uneven pressure. Otherwise I'm having a hard time believing it could get roasted this quick; hard launch or not.

 

[Big MAK]

Had a nice talk with Peter. Since it smoothed out so much the last couple days we're thinking there was just a little ceramic residue left on the flywheel after getting on it. I shut it down right after running; so it 'baked on'. Now it's been worn off.



So I'm going to leave it until February when I'll probably upgrade to FE for sled pulling.

 

[mattymac]

I have seen my fair share of SBC DD and I have yet to see one that actually works. They either make a ton of noise, they have a hard time dissengaging completely, or you cant shift them.



Mac, I think if you go to the 3850 lb. clutch you need to upgrade the hydrolics on your clutch, Ive heard of the new ones blowing out.

 

[Big MAK]

Yep; I agree that for the '03 and up you need to upgrade hydraulics to the 94-97 slave and master cylinders. Did that. SBC will probably be offering the slave and master as a kit soon.

 

[Got Smoke?]

Yep; I agree that for the '03 and up you need to upgrade hydraulics to the 94-97 slave and master cylinders. Did that. SBC will probably be offering the slave and master as a kit soon.

They are, I talked to him today!

 

[Fred Swanson]

Makes a big difference in the feel of the SBC DD.