Haha. Glad to see folks want to hear how it ends.
Ok, so we had put the car on the trailer Friday afternoon and were headed back to the city to pull the transmission. Matt was on his way to get a clutch kit, which was fortunately stocked locally and reasonably priced at ~$112.
We took a couple hours to grab some food, then went to work.
We had the transmission out in an hour or so and immediately saw some mangled teeth on the pressure plate diaphragm spring. When we disassembled the P-plate we found the friction surface (huge cast-iron ring) had cracked completely though in two places and another large crack was almost completely through the ring, leaving it in two completely separate pieces. "Well there's yur problem!"
We didn't have a good way to resurface the flywheel and it actually looked pretty straight against a precision straight-edge, so I hit it gently with a flap disk to de-glaze it and put the new clutch-disc, p-plate and TO bearing.
The transmission went back on without much hassle and we packed everything back up. After getting the car back together, I went for a quick test drive and almost immediately heard a horrible banging noise from the driveshaft. Car went back up in the air and we found a couple of driveshaft bolts that hadn't been fully tightened - whoops! While giving everything another good inspection, I also discovered a huge crack in the exhaust pre-cat. I had seen other teams knocked out of ChumpCar for sound violations, so I spent another couple hours with John and Darius making some patch panels and welding the exhaust back up. Finally we finished up and headed home for a few hours of rest.
I decided to drive the car home so I could test everything out and do some clutch break-in. The car seemed fine and I did as many low-speed, low-torque engagements as I could to mate the clutch and flywheel. All was good and the car got a few hours rest in my garage.
The next morning, we all hit the road. I was driving the Wrexus again and spent a good bit of time on the highway engaging and disengaging the clutch with cool-down between to facilitate break-in. Everything was still great and we made it to the track with a little time to spare.
The team did some more last-minute checks as I put on my gear and I pulled into line in the pits just as the pace truck started leading cars out for the pace laps to start the enduro. I think I was right behind the BioHazard MR2, actually, which would go on to the overall win 14 hours later.
My girlfriend of 12 years, Marnie, was on the radio and I told her to go check with timing/scoring to make sure our transponder was hitting, so we could come in to fix it quickly if it wasn't working. After just one lap, I heard her say over the radio that everyone's times were coming in and they would be going green soon. Another lap later and she gave me a great jump on the field again as I heard the "Green, green, green" and saw the double yellows go down from my position in turn 10. I managed to blow by 3 or 4 cars including BioHazard before everyone caught on that we were racing.
The car was running great, and I made a few more passes. After another lap or two, I went to make a shift and the clutch pedal went to the floor and stayed there. Crap.
I call into the pits and told the team to get the 10mm, a pan, and fluid to bleed the clutch and that I would come in after another lap.
I realized we hadn't bled the clutch the night before and it hadn't occurred to me that it would be a problem since everything seemed fine once the new clutch went in. There had been no leaks and no sign of issue on the drive home or to the track.
I pulled into the pits, with the clutch just barely working well enough to get the car going after stopping at control. The guys threw the jack over the wall and the car went up again.
I was hoping this would be a quick stop, so I kept my belts on and talked Matt and Josh through the procedure over the radio.
A few minutes later, we were back in business. The pedal seemed good and everything appeared to be working and leak free. The car came down and I headed back out, just a lap or two down.
The clutch almost immediately went to the floor again and I called back to the pits once again telling them I'd be back in after another lap. However, as I circulated sans clutch, it occurred to me that the car was totally driveable still. In a strange coincidence I had been practicing my left foot braking and shifting without a clutch in my old Celica recently, as preparation for some future rally driving I imagined I might one day take on. So, I decided to stay out.
I ran the rest of the two hour stint with left foot braking and right foot gas and never once touched the clutch. It was great. The car was one of the quicker ones down the straights, and as I learned the track, I was able to keep up with all but the most nimble cars in the corners as well. The time and laps flew by and soon 10:00 AM was approaching - time for a driver change.
I called in the stop and pulled into pit-in on the next lap. I had to cut the engine at control to get the pit timer and bump-start the car in 1st gear using the starter, but it worked fine and I pulled up to our stall.
The guys came over the wall for fuel while Josh helped me get out of the car. After the fuel was in, we took another couple minutes to try adjusting the pushrod for the clutch pedal/MC. It seemed to work and we sent Josh out. He turned a few laps before the clutch went to the floor again. He came back in and I told him to just keep driving with no clutch. On the way out of the pits though, the clutch started slipping (a whole new issue). I'm still not sure why, but I suspect that the slave cylinder was seizing, causing most of the issues we had.
Josh was concerned about the slipping, but I told him to go for it, since we didn't really have a better option (no parts stores could get a slave or MC for days). Josh pulled out of the pits and made it halfway up the hill from turn one where the slipping got so bad that the car wouldn't go any further. He was towed in a couple minutes later.
When the car final made it back to the paddock, I hoped in again and gave the car a try. There was no clutch, but the car started up and would drive like it had a super loose torque converter. Accompanied by grinding noises from the transmission.
We decided the clutch was in fact toasted and started considering our options. We could get another clutch, but without a new slave cylinder, or at least a properly resurfaced flywheel, there was almost no chance of a successful repair that would last the race. After a few minutes of discussion, I decided that the best plan of action was to pull the trans in the paddock and weld the clutch hub to the pressure plate if there were no other obvious solutions. This would allow us to continue with no new parts and would be a reasonably robust solution.
I called Greg who was sleeping at my place in Atlanta, waiting for his evening stint and asked him to start heading up to the track with his suitcase TIG welder, some scrap metal and my angle grinder. The rest of us set to work pulling the transmission again.
Here's what we found when we pulled off the transmission about 40 minutes later.
All that fluffy stuff coming out of the diaphragm spring teeth is cancer (clutch disc material).
Here's one big chunk wedged into the p-plate.
And here's the p-plate with the clutch disk sitting on top of it. If you're not sure what you're looking at, there's supposed to be a ring of friction material riveted to all those little petals on the clutch disc. This is how we found it...