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Do flywheels break apart?

I keep thinking I should get a steel bellhousing for my LS/CD009 swap thing I've got going on now. I really should have pondered that more before buying an aluminum housing.
 
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blkaplan said:
A flat flywheel is less likely to blow than a dished unit for a few reasons. The flat geometry has less stress risers then the dished style. The lower weight has less inertial forces as well.

With a dished wheel, having a continuous dish contributes to keeping the unit structurally sound. If you have divisions between the bolt holes for lightening purposes it makes it unstable and can lead to problems.

Better off to have a flat flywheel and use individual pedestals like John V has done in the past then having floating islands that are integral to the unit.

They are both made from cast iron, which can both having problems. One nice thing about cast iron is wears better than steel.

When it comes to high performance flywheels, no one makes them from cast iron, its always steel.
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I do have a fidanza aluminum flywheel in my Toyota, it sees trips to 8250 rpm almost every time I drive it. I replaced the steel friction surface last time I did the clutch but probably didn't need to. Too bad they don't make something for old ass rwd Volvo's. I think it weighs 7.5 lbs or so
 
VB242 said:
I do have a fidanza aluminum flywheel in my Toyota, it sees trips to 8250 rpm almost every time I drive it. I replaced the steel friction surface last time I did the clutch but probably didn't need to. Too bad they don't make something for old ass rwd Volvo's. I think it weighs 7.5 lbs or so
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An aluminum flywheel is a different beast, its not made from cast so its much less likely to fragment and grenade... The pieces of metal also are much less dense so if it does let go... the fragments have less energy behind them and less ability to penetrate surfaces.

Aluminum can have its own failure methods but exploding is rarely one of them from what i have seen (i'm sure someone will correct me if i'm mistaken)
 
VB242 said:
Too bad they don't make something for old ass rwd Volvo's. I think it weighs 7.5 lbs or so
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For enough money you can get anything made. Tilton made this one for me to fit a B18/B20 6 bolt crank.

6BoltFlywheelTilton.jpg
 
hessam69 said:
What steel/billet flywheels are available with LH 2.4 sensor holes?
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I know Yoshifab's setup uses a steel flywheel.

Wasn't going to go that route due to the cost but after reading this I'm reconsidering, I like my legs very much. Is this really only a concern for "sik nasty burnout br000s" turning 7K all the time? My car's a daily/occasional autox car, are my concerns unwarranted?
 
It's not nice when a flywheel lets go. Years ago I worked on a 67 Vette big block, the fly wheel blew, took out the glove box and exited through the right cowl vent very cleanly.
 
blkaplan said:
An aluminum flywheel is a different beast, its not made from cast so its much less likely to fragment and grenade... The pieces of metal also are much less dense so if it does let go... the fragments have less energy behind them and less ability to penetrate surfaces.

Aluminum can have its own failure methods but exploding is rarely one of them from what i have seen (i'm sure someone will correct me if i'm mistaken)
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I'd love to! (I know you know all this already, but others may not). Most aluminum alloys v. any quality ferrous metal, steel has much better fatigue strength and ferrous metals can be designed for infinite fatigue (unlike aluminum). Many ferrous alloys are also preferred for fracture toughness (plastic failure rather than having catistrophic fracture failure). However, when things are rotating at high speeds, the inertial body forces become a huge part of the equation. This explains why aluminum fly wheels exist and why turbofan motors wouldn't exist without Ti-Al6-4V titanium alloy. With centripetal acceleration, specific strength is more important than ultimate tensile strength or fracture toughness.
 
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Yeah aluminum has a lifespan that is related to shock and load. Think about planes, they are designed for a certain amount of take offs and landings and then they are parked in a desert, cause they are done. Aluminum will break with repeated shocks and load stresses on it. Why I don't like an aluminum framed dirt bike, or bicycle. IT will break given enough burnouts.
 
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