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Do flywheels break apart?

Yes they can, depends on some things or not. Here is a video of the damage, everything totaled, the car, the motor, the trans..

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Some have gotten lucky and they come apart at idle so nothing gets destroyed, me it came apart at 7k doing a burnout at the drag strip... Plus Honda boy and his scratched bumper progressive insurance co paid him 600 and lost my Progressive insurance dropped me for commercial purposes. High school drags I had to pay to drag. Funny thing is when you buy ticket to go into drags it says right on ticket nobody liable for nothing enter and die at own risk. Honda lover parked right at pit row closest to burn out box and wasn't even racing. Progressive beetch needs her white look muddied bad.

Nowdays I have three billet steel flywheels, all I use. I got Safeco insurance now, still way to expensive. I pay 100 a month for one old 90 wagon. My 1960 chevy bus motorhome is 150 for a year.. Nothing makes any sense.
 
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Neat video but how do you know it was a dog dish flywheel? The car frame didn't even look like it got bent. Nothing blows out the hood at all. Looks more like a rod threw the block video. Look at my damage video. The whole car got twisted and it was on fire and the hood blew half off and in two pieces. Parts of the flywheel flew 100 yards.
 
Note that your feet are more in line with the flywheel in a 240 than in a 700/900 series. The pedal box/firewall is just a couple of inches forward. I'm not sure if it's in foot smashing range or not, but it's that much closer to it.

I think some of the exploding dogdish flywheels were modified in some way or another, usually to lighten them. I'm not sure if Simon's up there was or not.

I stuck a JohnV billet steel flywheel on mine as well. No use worrying about that sort of thing, plus the billet steels are about half the weight of the dogdish (+/- a few lbs).
 
A little searching by the OP will show some pretty dramatic failures -- not only flywheels but clutch discs and pressure plates as well. The best protection is quality parts AND steel bell housings that are designed to contain those type failures.
 
I built a 2 piece scatter shield for the M400 in my race car out of ?"x 4" steel plate in order to comply with the rules (and for my own safety) using thick wall tubing and long allen bolts in place of the bell housing bolts to secure it to the trans. It hugs the bell housing very closely as space is at a premium in the chassis. It's open at the bottom on an upright mounted engine mainly for ground clearance. It might fit an M45/6/7 bell housing since they're they same pattern but I've never tried. I'll see if it fits one and post a pic tomorrow if I have time.
 
hessam69 said:
Do they? In particular the dog dish in front of an M47 in a 240

I need my legs
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Because they are iron..and there are little microscopic nitrogen bubbles lurking inside iron (unless it was cast in a vacuum chamber)..That's the reason.. If your unlucky and some of those microscopic nitrogen bubbles line up just right its basically like "tear on the dotted line".

Know in the metal world as nitrogen embrittlement..

That's why I made steel flywheels...they are tougher..
 
sbabbs said:
Neat video but how do you know it was a dog dish flywheel? The car frame didn't even look like it got bent. Nothing blows out the hood at all. Looks more like a rod threw the block video. Look at my damage video. The whole car got twisted and it was on fire and the hood blew half off and in two pieces. Parts of the flywheel flew 100 yards.
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I have no idea. Your car looks like it took more damage so maybe it wasn't the dogdish, but a rod or something
 
Funny how memory fades over time. I thought I left the bottom open but obviously I didn't.

RedblockScattershield1.jpg


RedblockScattershield2.jpg


RedblockScattershield3.jpg


It almost fits. A little trimming around the clutch cable boss and it would go right on. Note the engine torque brace incorporated into the shield.
 
VB242 said:
How about the flat flywheels? I assume they're a little safer since it's a uniform mass, are they made of iron or steel?
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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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