Huckleberry wrote: ↑Wed May 24, 2023 2:13 pm
golftdibrad1 wrote: ↑Wed May 24, 2023 9:47 am
What size MC and SC are you running? do you think the bigger MC could have caused the seal to blow on the SC? The other thing to check might be for bottoming, ie if the stroke of the slave/master combos are all good, maybe the clutch pack is bottoming causing your fluid pressure to spike? This won't do favors to your thrust bearings either.
Curious to hear what you find.
The slave is a Tilton 8100 hydraulic bearing. Their website lists the piston area at 1.215 sq.in. The master is a 1" bore Wilwood with a 1.100" stroke. The 1" bore is the only way I could get the clutch to release, and it still took almost the full pedal travel to get it done. I think I just had the piston right on the edge of the seal and the high RPM shift was enough to dislodge it. I looked in the bellhousing last night and the piston is stuck out with the seal folded over. I'm hoping the release bearing itself isn't damaged and I can just get a new seal kit, but I won't know until I start pulling things apart.
I was in the middle of the .100" - .150" bearing clearance (.133", if I recall), so I'm going to have another spacer made that puts me right at the minimum .100" clearance. I may also need to brace the firewall, as I think flex may be stealing some of the effective stroke of the pedal. Hopefully, those two things will get my clutch working a bit better.
This?
https://tiltonracing.com/product/8100-s ... e-bearing/
If so, Tilton is listing this bearing as a 0.70" maximum stroke.
The 1" bore of your MC has an area of 0.78in^2. 0.785 * 1.1= 0.8635 in^3 volume displaced
On the slave, 0.8635in^3 / 1.215in^2 area = 0.710 in displacement. Sorry to say my dude but i think you overstroked the MC/SC combo.
https://www.wilwood.com/PDF/Flyers/fl162.pdf
Reading up with your disengagement woes... I think you maybe still had air in the system. Continuing to up the MC size just made compressing it easier to enact the force you needed to the SC. The air may have worked out some (big vibrating car) and then you could fully stroke that slave....then the oopsie.
In that same thought...a SMALLER MC should REDUCE pedal effort while INCREASING stroke to do the same work/travel on a given SC. Referring to the chart by our good buds at wildwood notice how for a given pedal ratio (column) pad force INCREASES for a SMALLER MC. This is just like how a jack works, small piston with big stroke / makes big piston move little with big force.
I'd look at what it would take to be closer to the minimum side of the spacer spec and drop the MC a size or two. That should help reduce your firewall flex to via lower force inputs.
Final thought as you resolve all this: Pedal stops on custom builds are vastly overlooked and necessary for the throttle and clutch. Us humans can produce incredible amounts of force with our legs, and when multiplied through adrenaline and levers things WILL break. I had to add these on the kit cars. I suspect once you resolve your MC/SC clutch issues you can rig something easy enough, but make sure to look at the throttle too. You can bend all manner of expensive shit on the throttle, linkage, pedal itself, snap cables, etc, etc.
Good luck.