Flywheels, harmonic balancers, detonation = spun bearing

[Desperado]

As you know many of us have had spun bearings over the years, but what I'm starting to wonder is what is the true cause. It is the nature of the beast for things to break over time. When there is at least 2 objects such as metal working to greater, or against, over time one or the other is going to fail.
So I'm starting to wonder if lightened flywheels and or lightened pulleys can cause premature spun bearings.
I'm starting to wonder how many of you had stock parts when you spun your bearing. Was detonation involved? At what lvl of hp is counter productive with lighter flywheels and pulleys.

[anyonebutme]

Spun bearing only has a single cause: crank touching the bearing itself.

Where it gets complicated is WHY did the crank touch the bearing. And the first answer is "because the oil wedge didn't have the load capability of the forces acting on the crank". several steps down you have "contaminated oil" and "low oil pressure".

I've never spun a bearing on my engines and I have the lightest crank pulley and flywheel available, but I also don't make any HP (I only trap 113 or so) so the crank isn't flexing all to hell and back, but enough to wipe the center mains to copper after years of abuse.

[mb3000]

I'm running a Fidanza flywheel & 3SX stock sized lightweight aluminum pulley. According to science I should be damned to hell.

We'll see what happens..

[vr4tune]

3sx light weight pulley and a light flywheel with my carbon carbon clutch

[Alex3000gt]

On my stock 91 RT/TT, stock crank pulley.

STOCK.