I believe this to be the case. Back in 2008, I ordered a longblock from HTG with ACT clutch upgrade. Shortly after, I experienced the same symptoms as OP. HTG sent me a replacement shortblock under warranty and I never had any further crankwalk issues.

 

I think its certain people. I had the ACT PP set up for about 35k now with no issues and boosted for about 7k.

 

No bueno.



-Exedy hyper single + short oil starvation.

 

It's not just a problem with the ACT PP - this is an issue any time you go with a higher clamping force PP. Part of this is driving habits - leaving the clutch pushed in at a stoplight, or frequent stop and go traffic with a higher clamping force PP. The highest damage (in most cases) comes from starting the car with the clutch pushed in.

The higher thrust loads from a higher clamping force PP cause premature wear. Minimizing the amount of time you have the clutch pushed in helps reduce this wear.

To eliminate starting wear (being forced to push in the clutch to start the car) you need to bypass the clutch interlock switch, which is not hard to do at all. I don't know if the interlock has greater function in newer S2000s (2006 and later) - so I don't know if this a viable mod for the newer cars.

An oldie but a goodie:
https://www.s2ki.com/s2000/topic/619...switch-bypass/

I've been running the ACT HD PP for about 55k miles to date (2004 install). No issues as of yet (knock wood). My car is N/A.

On a side note: I'm about to switch to Amsoil's new Z-Rod (10W30) oil this spring (next oil change). I've been running Amsoil ATM 10W30 since the engine has been broken in. I'm doing this in consideration of thrust washer wear.
All of Amsoil's (and a lot of other manufacturer's) oils used to have a higher ZDDP content, but emissions requirements in order to meet API certifications have driven ZDDP and other additives out of most oils. I know most people think the ZDDP is only important if you run an older engines with flat tappets - however, after talking with Amsoil's Tech folks they believe the S2000 would benefit from a little more protection the ZDDP would provide the thrust washers. The only down side to the Z-Rod oil is it supposedly can damage the catalyst over time (never actually heard of this happening) and the oil is not designed for extended drain intervals. The latter isn't a problem as I stick to a 3,000-5,000 mile change interval as it is.

 

wait a minute I heard Billman say that ACT HD pressure Plate, ACT Prolite Chromoly Flywheel, and OEM disc and bearings is the best combo??

 

Yep. Many of us have ran it for tens of thousands of miles. I had 50k on mine and I have very little crank play. Bypass the clutch safety, and don't sit on the pedal at lights. It doesn't matter what PP you run.

 

Billman is running the Comptech chromoly flywheel, ACT PP, and OEM disc and bearings (I'm currently running the same). The Comptech FW weighs around 11.5 lbs, but is no longer available. The ACT Streetlight runs 11.4 lbs and the Prolite is around 8.6 lbs. The ACT is superior to the Comptech due to the fact the Comptech's ring gear is welded to the flywheel body. The ACT flywheels are one piece forgings.
The difference in the two ACT offerings is in how much material is removed near the outer edge of the flywheel (between the friction surface and the ring gear - where it counts for rotational inertia). The friction surface is the same for both ACT flywheels. All of ACT's flywheels are hot forged chromoly (both the Streetlight and the Prolight). I just confirmed this with Ryan Longmead at ACT (661)940-7555 (X101). They stopped producing aluminum flywheels for all the reasons I highlighted in this topic:

https://www.s2ki.com/s2000/topic/927...-the-flywheel/

This string can get painful to read at times (a conflicting point of view by another poster). But the info posted may be relevant to someone considering a lightweight flywheel. I provided links for reference in my posts.

 

Not again.

 

Having a couple friends that lost their motors to crank walk, and following the many cases online, I think the correlation between crank walk and ACT pressure plates isn't 100% clear, but what I did find was that many, if not all of the cases involved a loss of oil pressure at some point before the incident. Having a higher pressure plate doesn't help the case, but having an oil line blow off or running the engine low on oil will cause increased wear on an already 'weak' part.

 

simple YES or NO question.... Can I run the ACT HD PP, ACT Prolite flywheel, OEM disc and OEM bearings without having to worry about "crank-walking" my S?
I don't wanna bother doing the clutch bypass mod OR changing my driving habbits. The only reason I wanna go with ACT is because I have plans on going with a supercharger down the road ....