I drop the car off tonight, the trans shop who installed the Southbend will look at it on Wednesday; I plan to take pics and will report what we find.


If slipping occurs in a clutch, its either
a) too much torque
b) insufficient friction
d) insufficient force

a) clutch was slipping with no boost (wastegate open), probably 70% of stock torque or 130 lb*ft. Clutch should handle 300 lb*ft. Out.

b) friction: the seal was changed (and carefully installed) and hopefully no oil coming out. Any other way that oil can get into the clutch? Externally?

c) Clamping force: weak spring (brand new Southbend clutch). Out. Not engaging properly, 2 friction surfaces too far apart (flywheel wear, unlikely; too far apart?)

Aside from warp (clutch engages smoothly) and wear (pedal travel/engagement point of clutch is not at the end) , what else could be wrong with a flywheel (since this was the only thing (not resurfacing) we did not do by the books.

 

I believe that if you've got a flywheel that has hot spots that there will be clutch chatter, but I didnt think clutch slipping could arise from this. I'm also not sure if the southbend clutch kit is a direct bolt up to the stock flywheel or if you need to buy a southbend flywheel, im sure mike could fill you in. Just things to think about since you will have it all apart. If it is the flywheels "fault" then its going to be hard to blame it on the shop, as its not really there problem considering you gave them the parts to replace.

 

All the clutch kits are designed for the stock flywheel and most of the aftermarket LWFW's are designed to replace the stock flywheel. When ordering a SB clutch kit for the stock flywheel the only difference is it comes with a unsprung disk, while a sprung disk is used for a LWFW. The actual stack height and specs are exactly the same.

The SB kits are designed to add pre-load pressure, so basically when you install it onto the flywheel there is a slight gab between the pressure plate lip and the flywheel. When you install the pressure plate bolts it forces the pressure plate down to the flywheel. This is one of the reasons the SB kits have a low engagment pedal point.

 

Mike, does that mean they typically engage early in the pedal travel?
Currently, the clutch engages (estimate) on the 1/4 to 1/2 inch of pedal travel.

The only chatter that I can sometimes generate is in first gear under certain conditions (not sure if I could repeatedly create those conditions).

Tomorrow, clutch will come out; I will post findings/pics.

 

Yes, more so on the SS(Stage 4-5) then the HD(stage 1-3).

When people ask me what clutch they should get the very first question I ask them is where would they like the clutch to engage on the pedal travel. Well that and if they launch the car or if it is 100% daily driver.

Make sure to email me some pics, if it is a clutch issue I will make sure it gets handled.

 

"Currently, the clutch engages (estimate) on the 1/4 to 1/2 inch of pedal travel."

Would you say 1/4 to 1/2 inch engagement from end is typical for the stage 3? Or is that an indication that something is wrong?

Could the brake fluid (as far as I know, the hydraulic is only used to DISENGAGE the clutch) or the brake system have any effect on the clutch (preventing full engagement/pressure)?

 

If you mean the engagement is all the way at the top of the clutch pedal (just like stock) then yes there is a problem. Either there is very little clutch material left or the flywheel stack height is way too much, both of these will allow the disk to be completely released much sooner then it should. If it is too much there wont be enough clamping pressure on the disk, this would allow the disk to slip even when the clutch is fully engaged.

 

Yes, definately 'at the top' (pedal movement between first engagement and fully relieved is less than 1/2", what I call 'late engagement'.
It can't be wear (no clutch material left; 3000 miles highway). If the flywheel stack height is too much:
- how can the shop check/verify. Can you send detailed instructions?
- what could cause a 'too much' stack height'?

Shop just called; work could be delayed into later today or even tomorrow.

 

I emailed SB letting them know about the issue you are having and to see if they can give me some specs on the flywheel height.

 

thanx