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Gotta question of the physics type, specifically Newton’s Third law vs. causes of crank walk (in my case just damage in general). Ok I just got done installing an ACT clutch system (as seen in the car pics forum) and I was a little concerned about me beating the hell out of my bottom end. I have had a UDP on the other end of the crank for 25k miles allowing vibration to beat the hell out of my crankshaft bearings, but that’s another story. Ive heard a lot of people to include someone here that say the crankwalk issue is mainly caused by to much pressure from aftermarket pressure plates smashing the thrust bearings. I see a problem with this idea. Now if you know newton’s law it states “All forces occur in pairs, and these two forces are equal in magnitude and opposite in direction.” In other words as the pressure plate pushs on the clutch that pushes on the flywheel that pressure and if something didn’t stop it the Pressure plate would move away from the clutch or accelerate the clutch away from it. Now the crankwalk being caused by the pressure plate implies that force coming back is held by the thrust bearings and the crank. I see a problem with this theory. Where would the pressure plate get its leverage from to exert that much pressure on the clutch disc if it was the crank pushing back?? If it was the crank that pushed back the PP would push away from it. So what does that leave? The thing holding the pressure plate to the flywheel, the bolts. Now we have the pressure plate pushing against the clutch at the same time the pressure plate is trying to move away from the clutch. An equal amount of force has to be held/applied by the bolts/flywheel. So now we have a clutch disc being smashed against two objects exerting force on one another. Now acceleration or force thru the crank should be low if any is experienced as the clutch engages and disengages.

First Picture show a very basic image of the PP, clutch, and flywheel.
Black=Flywheel
Red = Clutch
Blue = Pressure plate


Second Picture shows the basic idea of the PP forcing the clutch against the flywheel


The third illustrates that if they have no acceleration, or stay still, there has to be an equal amount of force being applied in the opposite direction of the PPs movement.. toward the flywheel. I think its being held and equalized at the bolts.


To support this idea when a g2 eclipse has crankwalk one symptom is hard shifting when turning left.. the left turn is acceleration the crank away making it had for the clutch fork to engage the PP correctly making the shift hard. Now that is an outside force pushing it… but if the PP pushed the crank every time the clutch engaged the flywheel it would move causing the hard shifting issues.

Whatcha think? Am I missing something? Either way I love that clutch and Ill deal with something breaking later if it happens.

I know this isn't exclusivly N/a but its also not offtopic. ;):

[Edited by WytchDctr on Mar 5, 2006 6:44 PM]
 

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Ok, here is my experience with this in my ex job , there were many crankshaft badly damaged that were brought to the shop and the owners said that the cause was a bronce rigid pucks clutch (no springs) . as we saw the clutchs and flywheels damage you can really see that the clutch was been extremely grabby making deep scars on the fly wheel so they would not take resurface due to poor measurments (badly damaged). There were 2 cases that 1 or 2 main bearings were welded to the crankshaft :dead: If one thinks about it there is many reasons for these to hapen (damaged crankshaft), like bad clearance,faulty oil pump etc... but the strange thing is the beating that those flywheels took and the guys keep talking about those rigid bronce clutches . i would say stay away from those NO SPRING bronce clutches
 
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