What a surprise right?….This is getting really annoying. Below is my whole thought process through this, some of it is more for my own understanding later down the road, but I’m open to ideas.
The clutch had been making some excessive noise this past summer and occasionally a strange feeling pedal so I told my self I’d tear it apart and check out whats going on. I wanted to see how my new pilot bearing was doing and was expecting to find a bad throw-out bearing due to the strange clutch feel and noise…boy was I wrong! For starters, the pressure plate had bent teeth (see picture below). So I took this off and inspected the clutch disc and pilot bearing, the disc looked like it was about to strip out AGAIN and the pilot bearing was nearly completely trashed.
Alright, my first thought is something isn’t aligned properly as it should NOT be doing this. Looking deeper into the problem I noticed that the pressure plate teeth weren’t bent but that the pressure plate friction surface was crooked inside the housing. I was able to hit the friction surface a couple times and it straightened out which in turn corrected the teeth. When I inspected the flywheel it appeared to have a little hot spot where the friction disk was closest to the flywheel.
My conclusion to this whole problem is now pointing entirely to a defective/bad pressure plate. I’m surprised to say this as I’ve always heard ACT was a very good brand. Due to the somewhat seized pressure plate, it was creating an unequal amount of force on the clutch disk, more so on the one side, which normally would have an equal and opposite friction force on the full face of the disk. However, due to the uneven clamping load there was a smaller friction force on the opposing side of the clutch disk. This caused the input shaft to be pressed against the pilot bearing, wearing it much more than it normally would. As it wore the input shaft would be forced off-axis and cause added friction between the input shaft and clutch splines.
This huge chain reaction almost brought me to strip out ANOTHER clutch disk and input shaft. So glad I caught it before it ruined another transmission. Reason’s I do not suspect alignment issues as much are simply due to the fact that everything lines up very nicely when assembled, and more so due to the fact that the pressure plate was obviously seized and from what I remember the RPS pressure plate was perfectly fine when this happened the first time.
Solutions to this problem are going to be a new clutch (again…) and redesigning the pilot bearing just in case (again…); the new clutch will instead be a Comp Clutch Strip Series 0420. I will also be re-machining the flywheel spacer to press fit a bronze sleeve into, then a new Nismo roller pilot bearing will be lightly pressed into the sleeve after making sure everything is concentric. Let the fun begin!
What’s left of the bearing.
And what the splines of the ACT clutch disk looked like, as you can see they were getting very worn and sharp.
In other news, I got material to get my subframe spacers made. Work is scheduled to be done on Friday!
Also got some drift spares with tax return $$, tires should be coming tomorrow!
XXR 527 – 18×9.75 +20 (they sent me one with a +25 offset… hopefully to be corrected soon)