protodad

So I finally bought an RX-8. 2005, 6 speed, silver. Previous owner installed Racing Beat intake, JIC suspension (!) and Exedy twin Carbon clutch (also !).

The car runs great but it is obvious the clutch was installed wrong. The shifter doesn't want to go into 1st or reverse, but generally shifts the other gears fine. It stalls in 1st or 2nd with the clutch pedal on the ground as if it is still engaging. When I got it home, there is easily 2 inches of free play in the pedal before it starts doing any work. Before I pull the trans of and check the throw out bearing and fork, I had planned to adjust the pedal.

My problem is, the lock nut on this thing is seriously on tight. I am turning the nut counter clockwise but the bracket that attaches the "rod" to the pedal is seriously flexing when I start to push hard. Is this normal (doubt it)? Do I really need to pull that hard on it? In addition, the adjustment nut is right against it. Do I need to hold down the lock nut and turn the adjustment side?

The car is hardly drivable the way it is but I don't feel like breaking a clutch pedal tonight. Thanks in advance.

RIWWP

iTrader: (2)

You have to free up the lock nut first, move it up the shaft out of the way, then adjust the adjustment nut to suit. Otherwise the adjustment nut won't move. If needed, you can pull the clutch pedal assembly with only a bit of difficulty. You will have to adjust it on the car of course, but if things seem stuck, pulling the assembly to get everything loosened up might be a good idea.

There isn't much on here about the clutch you have, though be aware that if you can't seem to get it adjusted correctly, it could easily be a clutch starting to fail early. The Exedy Stage1 has that problem rather badly. If so, pull the starter and take a look through the hole in the bellhousing where the starter sits to see if there is shredded clutch material all over the place. If you end up having to replace the clutch, just go back to OEM (from BHR or Mazmart). It's a lot lighter, but plenty of torque capacity for the engine, fits perfectly, and lasts a long time.

protodad

The twin disc is complete overkill for this application. I don't know what he was thinking.
As for the locking nut (the 12 mm one right?) that is the one that won't move at all. It is completely jammed between the bracket and the adjustment nut, no space between either.

I may have to drop the pedal...

RIWWP

iTrader: (2)

Yeah, if I was in your shoes, I'd pull the assembly to figure it out. Working up in there can get rather painful if your body is similar in shape to a human. (which I assume it is)

protodad

It hasn't been fun so far.

protodad

The diagram I was looking at showed the 12mm locknut against the bracket (closest to driver seat) and the 10mm adjustment nut on the firewall side (as part of the adjustment rod assembly?).

Do i have that backwards? The 10mm nut didn't want to move either but I didn't try too hard.

logalinipoo

Check the bracket closely. Lay down there and press the pedal while looking at the spot welds on either side. It could be broken

protodad

From Exedy about the carbon clutch...

"d. EXEDY Stage 3, 4 Carbon** disc with sprung hub center section is a great choice for the “dedicated race car” who wants a very smooth engaging clutch with little to no driveline vibrations. The carbon disc is a very lightweight resulting in extremely quick shifts.
e. EXEDY Stage 3, 4, 5 Carbon** disc with solid hub center section is a great choice for the “dedicated race car” who wants a very smooth engaging clutch that is very lightweight for extremely quick shifts.
**Carbon clutches are not recommended for street use due to the inconsistent friction coefficient from hot to cold. Carbon clutches require a warm up procedure before being driven aggressively. Due to this nature we only recommend carbon clutches for race only applications or to customers who completely understand the characteristics of a carbon clutch. A very big misconception
of a carbon clutch is that the vehicle is warm so isn’t the clutch? These units work excellent on dedicated race cars due to the driver being able to do the warm up procedure prior to the start of the race and every time driver upshifts or downshifts at higher RPM he is continuing to add heat
to the clutch disc. In a street car you often stop at lights, drive in a specific gear, or shift at a lower RPM not allowing adequate heat to be given to the clutch disc. Without heat in a carbon clutch the friction coefficient is significantly lower than when heated. It is at these points in a street car that the customer may decide to put the pedal to the metal causing the clutch to slip and wear out prematurely due to inadequate heat being in the clutch disc."

Anyone want to buy a slightly used carbon clutch?

RIWWP

iTrader: (2)

Not with that sales line

protodad

So finally figured it out and adjusted the pedal so there is not as much free movement before the slave cylinder is engaged. However, in gear (first or reverse) with the clutch pedal on the floor it still acts as if the clutch is slightly engaged (the car moves forward or backward). Do I just keep adjusting the pedal or is there a larger issue here?

RIWWP

iTrader: (2)

There is a specific spec to measure to get it right, but it wouldn't shock me if you have a deeper problem.

Basically, when you adjust the plunger farther into the clutch master cylinder, it will move the disc farther off the flywheel for the same pedal movement, but you will also start preloading the release bearing, accelerating the wear of that bearing.

If the disc can't be fully released with the pedal down the whole way on a properly adjusted clutch pedal, then one or more of:
- Hydraulics failure (less movement is being transmitted than should be)
- Hydraulics fluid contamination (fluid is compressing reducing movement)
- A burst clutch disc "thickens" the clutch effectively, making it not possible to separate (ive had this happen)

There might be another option, but these are the 3 most common. You can check the 3rd by pulling the starter and looking through the hole it mounts to.

protodad

SUCCESS!
Ok, it just needed to be engaged more. Still about 1/4 to 3/8 inch play in the pedal. Goes in all gears with no issues now.

Unfortunately I disconnected the battery while working on it and it dies at idle now. Definitely wasn't doing that before. Any idea if these are related? Does it need to relearn something?

kevinande

It just needs to relearn your fuel trims. Turn your key on, turn the steering wheel all the way one way and then the other. stomp on the brake pedal approx 20 times in rapid succession. when you see the oil pressure guage sweep all the way across your done. you just reset the computer. It may idle normally right away, or it may take a few drive cycles.

protodad

Awesome. You guys are the best

04Green

iTrader: (1)

Looks like you got it.

For the trim learn, start it cold and let it idle for 10 minutes. It will learn most of what it needs. If you reset, and start it hot, you life will be hell. If necessary, re-20 stomp with it cold and start over. For the last little bit, turn on the AC. That will raise the idle a bit and help it run.

protodad

Works great now. I did a combination of holding mid and high rpm for 15 sec each (didn't work) and holding at sub 1000 rpm for a while (3-5 min?) and that fixed it.

Either way, it runs great, performs great, and is all all around amazing. This doesn't completely surprise me, I had an FC that saved my stupid life when i was a teenager. Driving stupid and it was controllable in a corner it shouldn't have.

I may have to replace the throw out bearing still (and fork) but my brother in law might do it for a few cases of craft beer.