Clutch Failure

[Colin Byrne]

On the Last corner of the Last stage of the last day of Targa we got a big bang and then a bad vibration through the driveline.  My first thought was driveshaft, but when we pulled up the vibration was still there and on take off there was a some bad shuddering so we figured it was the cltuch.  Well the car got to the finish line and we had more pressing things to worry about (mostly getting a beer).  The car then drove back from Hobart to Luanceston, then from melbourne to Paul's workshop in Berwick, the vibration did not get any better!.

This arvo i had a spare hour so i ripped the gearbox out and pulled the pressure plate off.  The photo's tell the full story, 2 out of the 3 flex plates and broken all the way through, and the third one was holding on by the skin of it's teeth.  This was a brand new Sachs pressure plate that had the rivets drilled and and unbrako bolts added, including adding a 3rd bolt.  Looks like i might have to upgrade to a Porsch one next ?

Also managed to wear nearly 1.4mm off the Kevlar reinforced friction plate, so it's pretty much time for a new one, turns out 8 hard starts a day with a close ratio geabox comes at a cost!

[McAnnik]

   PM sent. I may have the answer, then again, maybe not!!!!.....Regards......Ian

[Colin Byrne]

Hi guys,
Well I couldn't find any great solution to my clutch issues without going to a full AP paddle racing clutch setup but with all the road driving we have to do during rallies I really wanted to keep a more standard setup (not to mention the cost!)
   So here are a couple of photo's of my first attempt at a solution.  The tags originally failed as the couldn't handle the torque so I've added 3 sets of steel "fingers" that are bolted to the cover plate and slide up and down in a slot that I machined into the drive plate.  These fingers should now take the majority of the torque and take the load of the spring tags.
   Still need to get all balanced before I can put it back in the car, hopefully have it finished so I can test it out at the island in a couple of weeks.

[Colin Byrne]

quick update, got the clutch balanced during the week (almost not required based on the tiny amount of material removed) and managed to take it for a test drive on Saturday, all seems good, I thought there may be some knocking of the new steel "Fingers" resisting the torque of the drive drive plate but it was completely silent and the clutch engauges/dis-engauges perfectly,  all ready for a good thrashing at the island on Saturday, can't wait!

[Colin Byrne]

After a very cold, wet and windy day (but lots of fun) at the island the clutch appeared to work very well.

And finally after about 10 years of trying I managed to crack the 2 min barrier in a 105 with a time of 1:58.8. Considering the conditions pretty happy with that!

[Frank Musco]

Congratulations on breaking the 2 minutes.