my2001boxster

So its time to replace my clutch and I am considering a lightwheel flywheel. Is there any real reason not to do this? I've heard talk of this being a bad idea, is there any proof as to why or is it just talk?
FYI, my car is a 2000 C2 cab.
Thanks,

Tony

eggodynamics

Well according to reputable sources installing the lightweight flywheel should only be performed along with a harmonic balancing of the new assembly to insure vibration doesn't weaken and break the stock crankshaft over time. The stock crank was designed with specifications to match the stock flywheel, and you definitely risk lowering the reliability of the engine by installing it. Not to overstate the obvious but a broken crankshaft is a game killer for the M96.

ivangene

if you like a 2 piece crank its fine......


on dedicated track cars it has been known to work ok, but for street and or street/track it has been known to be a very costly "upgrade"

Tbred911

what pieces exactly are they balancing?

ivangene

wallet - to crank

ltusler

I have a 2 piece crank. Although the engine ran thousands of race miles before it went. It was a 2002 3.6 with an X51 upgrade and some tuning. Now its a Flat 6 Innovations 3.8 with a number of goodies and the original dual mass flywheel all balanced. I don't know how much this means, but the new generation of engines now have a harmonic balancer installed.

YMMV
Lon

gota911

OUCH!! Sorry to hear about that ^ !

Macster

The crankshaft with any chain drive sprocket, rod/piston assemblies, and the flywheel and perhaps the drive pulley at the front the crankshaft.

In short all rotating/reciprocating parts.

The rods are made to have the same big end (with rod bolts/nuts and bearing inserts) and little end weights within whatever tolerance the engine builder believes is appropriate. The same goes for the piston assemblies: piston, rings, piston pin, and any piston pin locks/keepers.

Now in some cases the assemblies don't have to have the same weight but the heavier units are assembled at one end of the engine while the lighter ones end up at the other end, that is with the rod/piston assemblies being heavier on one end of the engine (perhaps the flywheel end) and getting progressively lighter as one moves to the other end of the engine.

Now opposing rod/piston assemblies still want to be very close to the same weight and this is obtained by judiciously removing metal from the heavier items or even by during the balancing phase selecting components based on their weight.

Sincerely,

Macster.

my2001boxster

Well I guess I won't do the lightweight flywheel.
Does the flywheel usually need to be replaced with the clutch? I have 77,500 on the car right now.

Tony

Barn996

ask Mfletch...he installed a LFW awhile ago and loves it.

Macster

Can't say. The flywheel may be reusable. Even if a bit worn they can be resurfaced. Not all shops do it or have it done, but a Porsche dealer tech told me they can be resurfaced and the dealer sends flywheels out to be resurfaced when they're otherwise ok to reuse.

Another reason the fw may not be reusable is if the dual mass feature not working properly.

Mechanic can test the dual mass feature by measuring the amount of movement the flywheel has. There's a callout and if the movement is within acceptable the fw can be reused. If not it can't be.

Sincerely,

Macster.

Pac996

Here's a short explanation of light and dual mass. Light weight the crank and engine take the torque effects when changing gears. With light weight you get a little fast spin up since you aren't spinning up the dual mass flywheel too BUT when popping the clutch you aren't getting backed up with the loaded mass of the dual mass flywheel.

Like the guys mentioned the dual mass leaving the drive train requires some conciderations. A guy can do it to be like a race car but like I always try to remind guys, race cars and engines get torn down and internals replaced along with bearings at intervals.

So how about I just say plan on regular tear downs for checks and services