slipstream444

To the OP - Sorry this thread kind of went on a tangent - but I think this may point you toward a different clutch.

I just spoke with John Lee (owner of Inline Pro), and he graciously spent a solid 40 minutes discussing this issue with me (as well as other performance related topics) - and he confirmed there is a crank-walk issue related to the use of high clamping force clutches in the F20/22 and K series of engines, quite commonly associated with the ACT in fact.
I will be switching to a different clutch in the next couple of months due to this fact.

FF2Skip

Wouldn't it be expected to see higher accounts of such things from an ACT PP because that is what most people have used to replace/upgrade with?

FWIW, I've been sc'd to 400 rwhp and have used John's 2.5L(current). I've been on the same diff(4.57's), clutch(oem), pp(ACT), and Comptech FW since '04.

slipstream444

A number of folks in the industry have pointed to the problems related to using the ACT PP, the increased wear and crank walk.

The direction of the thrust load created by the increased clamping force is essentially irrelevant. The thrust bearings/washers are designed to mitigate a certain load. Any load in excess of this specified margin = excessive wear, and ultimately crank walk.

The Carbonetics clutch in fact mechanically reverses the engagement. It has around stock sprung force, while greatly increasing the clamping force. The thrust load is not essentially a function of clamping force. The thrust force is a function of the spring force of the PP. The increased clamping force of a dual plate clutch like the Carbonetics clutch is due to the overall increase in surface area (two discs) times the spring force. Therefore you can nearly double the clamping force by doubling the surface area, while keeping the spring force at stock levels. This keeps the thrust load near stock levels.

The thrust washers/bearings in most cars are engineered to take a nominal load - somewhere around 130% of what the stock PP creates. I believe the ACT PP is very close to that engineering load limit.
If I understand it correctly, the S2000's PP exerts a force that tries to push the crank out the front of the engine, not toward the rear.
And even if the opposite were true, the input shaft of the transmission would not help. In that situation, the crank (and flywheel) moving aft (toward the input shaft) would contact the front of the input shaft, which would very quickly be evident in noise and vibration.

slipstream444

Absolutely true.

Sobe_Death

Slipstream, The stock clutch movement tries to pull the crank towards the back of the engine. The setup that Larry would be putting together for you (if I'm thinking of the same one) does a pull-push conversion to make it disengage like most other Honda's, e.g. pushing towards the front of the engine. Either way, you are correct about the problem with exceeding the limits of the thrust bearings. It's a bad thing.

Mind if I ask what you're having ENDYN do with your motor? I'm a big fan of their work and have been for years since I was tuning single cam honda motors.

Parker

S2KPUDDYDAD

Very interesting I am glad I read this thread. I run a Spec light PP with OEM disc. The engagement is lighter than stock but, the clamping force is about 30% greater.

On the flywheel question, you should be able to resurface it but, you will not know till it is out of the car and placed on the lath. The machinist will be able to tell you if it is safe to use.

You can send the flywheel to me if you like for machining.

RedY2KS2k

I think there are two different switches. The cruise control disengages at the slightest downward movement of the clutch pedal. The starter won't engage unless the pedal is fully depressed to the floor. That sounds like two different switches to me...

deathsled

bypassing the the clutch switch so you can start the car without having to put the clutch in in an effort to prevent crank walk is an oooold Supra trick.

I've got the clutch bypassed on my S2000 for the remote start and never push it in even when I'm already in the car.

03AP1

I was having problems with my S stalling out while decelerating with the clutch pedal pressed to the floor. Mechanics kept my car for a month before they noticed the crank was moving (toward the bumper) a good 2 - 3 mm. They said my thrust washers were either never installed or my crank ate through them. This was on a brand new engine w/less than 6k miles. My clutch setup was ACT pp w/ACT flywheel. Rest of the clutch setup was OEM.

I called Jeff @ Htguy and he replaced the block under warranty. Still running the same clutch setup. The shop said they thought my clutch wasn't lub'd properly causing the equivalent of crankwalk. Could it be my clutch setup that is causing this problem? Jeff @ Htguy said he hasn't had any problems w/his setup. Mechanics called ACT and they informed him that they don't recommend using ACT products with the S2K OEM setup.

slipstream444

I haven't had any problems with my ACT as of yet - about 22,000 miles on it to date. However, that's not to say it's not doing damage.

I bypassed the clutch interlock (wish I had done it sooner). It was actually pretty easy. The interlock switch is the switch located above the clutch position switch (releases the cruise - both switches look pretty much the same).
I just unplugged the connector and jumpered the terminals. It helps to unplug the clutch position switch connecter to make it easier to get to the interlock switch.
I think I'll eventually rig a switch. A switch is a good idea if your car is driven by anyone other than yourself - to keep them from screwing the car through the end of your garage with the starter!
I'm currently the only one that drives my car - so I'm not so worried about it right now.