Well thats the end of another year of racing for me.
Nationals weekend has come and gone with some good racing and some bitter disappointment. The car was performing quite well in the first qualifying session until it started bucketing down, managed to get my fastest qualifying lap in as a warmup lap before it started bucketing down properly, and then the V band clamp came of the exhaust and it dissappeared, never to be seen again. So we welded the primaries to the secondaries before Quali 2
Second qualifying session went pretty well, although i had a weird ignition issue at the end of that session. Basically it would hit something like ignition cut at ~5500rpm and wouldnt go anywhere.
Before the first heat we changed the coils and plugs and it seemed that the ignition problem was fixed, at least mostly.
The first heat showed up something a bit more annoying, we had a weird issue with it hitting redline oddly, but it was only happening around 7700rpm, so i just thought it was the ignition problem back with vengance. So we fiddled around with it some more, changed dwell settings and again its seemed to be fine while free revving.
Went out in the second heat and it just got worse. Quickly realised that it was actually the clutch slipping not the ignition dying. So after that race we started to pull the gearbox out, only to find that it got about an inch off the engine and then wouldnt go any further at all. Just jammed up solid.
Packed it in for the day and retired the next morning. Got it home after the end of the day and after dinner i pulled the engine and gearbox. After working through the starter motor hole i eventually managed to remove all 6 pressure plate bolts. This is what i found:
[IMG]http://a3.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s720x720/308345_10150464205150944_646995943_10816860_604287785_n.jpg[/IMG]
Bang, the clutch had let go in fairly spectacular fashion. I think the main chunks of the friction material were only being held in place by the protruding rivets. And im not sure whether the center damage was done by us reefing the box around to try and get it out, or whether it was done in car. Either way its busted.
The reason the box wouldnt come out was that the spigot bearing was jammed on the end of the input shaft, and that was holding hte friction plate together enough. When i started pulling the engine out the second of those springs fell out of the bellhousing 🙂 and the other had fallen out when we loaded it onto the trailer.
What i really should have done is looked at the data trace from the datalogger and i would have seen this:
[img]http://gallery2.plebeians.net/d/33446-1/rpmclutchslip.PNG[/img]
The green trace is the RPM and you can quite clearly see it slipping a lot from 7500rpm onwards. In the later races this started from about 5500-6000rpm and would just slip to redline.
Oddly enough this isnt the first time ive made an Exedy clutch go bang in this way, back in 2006 i did this:
[img]http://gallery2.plebeians.net/d/6925-1/DSC00383.JPG[/img]
Back then the friction material jammed up the clutch entirely and i couldnt disengage the clutch at all. Thankfully this time it held together enough for the two heats i did on Saturday.
Ohwell, thats the end of another year for me. Next year ill be moving to Vic, and hopefully we can start over again 🙂
Hoping to have the car rebuilt soon at least for transport. Thinking about doing a few upgrades while im at it 🙂