Thinking of lightening your flywheel?

[Dr-X]

Every couple of months someone decides to make a thread on whether they should lighten their flywheel (as in, machine it down). There's always a few people (like me) who suggest it's a good idea, as long as you dont value your legs. Here's some pics of a guy who blew his flywheel on his Mustang doing burnouts. The flywheel was stock, not lightened, and he was doing about 7800 rpm. This is FAR more likely to happen to a machined flywheel, especially one which has done 100,000+ K's already.

Remember kids, if you want a light flywheel, get a billet (or just dont bother getting a light flywheel if it's just for road use)

This is looking through the guard. Notice a severed brake line:


Here's pics of the headers. These a bent mild steel headers - shows the amount of force behind the busted flywheel:



What looks like a bent hose to the right of this pic is actually a steering arm. Gives you an idea of the force.


Rooted clutch assembly:



What he could find of the flywheel. Look at the ring gear, and how it's bent:




Here's pics from when he was doing the burnout:

Here you can see the explosion under the car:


Just in front of the car you can see a piece of debris:


Bang.



This guy was lucky, he kept his feet. His car suffered massive panel damage, including holes in the bonnet. It's likely that when the flywheel blew, it caused a massive inbalance in the crank, which at 7800rpm would have $&#$% his bottom end rightly. The car has no brakes (severed lines) and no steering.

[AJz]

F$#%ing hell, man thats nasty, thats quite amazing. Never really thought about what would happen if a flywheel blew up, now i know.

[CozmoNz]

Fuking OWNED.

mint stang though....

[Adamal]

Good post, X.

Should probably be made a sticky.

[gtz666]

poor mustang, maybe he might invest in a shield next time

[AJz]

Good post, X.

Should probably be made a sticky.

yea i was thinkin that after i posted.

[Alex B]

this happend to a cf beddy when dad was a mechanic at telecom apprently the frist thing they noticed was the gearstick dissapearing through the floor, the truck did a semi pole volt on the drive shaft

they never did find the flywheel

[AJz]

hahahhahah, im just picturing that in my head, thats nuts.

[Inane]

FAQ nomination

[Ebola_One]

this happend to a cf beddy when dad was a mechanic at telecom apprently the frist thing they noticed was the gearstick dissapearing through the floor, the truck did a semi pole volt on the drive shaft

they never did find the flywheel

SOunds more like teh drive shaft snapped & wasn't cradled.

Man, there's some royal ownage on that Stang... Imagine that in a FWD... bye bye driver. Be like a James Bond trap thing, laser cut up the middle, starting with the crotch...

[Alex B]

nar my dad had to fix it a so im prety sure it would be flywheel if he says so. Luckly it only did minimal damage to the block. The beddys where thashed any way typical linesmen!

[snwtoy]

Sticky/FAQ - can anyone find pictures of a fronter/4wd with a shattered flywheel?

Did a google search and surprisingly couldn't find anything

[blitza]

thats one mustang down....

[Dangerous_Driver]

haha amen another mustang down..
I had an aa63 sh$t a flywheel off a launch not that severe just split in the cracks that were allready there but anywho...

[RS13]

Then again, you could have 1000 other machined flywheels, that never break. It comes down to the condition of the flywheel, and the quality of machine work.

As long as you get a decent flywheel to start with, get it machined, then crack tested and balanced, I don't see any issues. Besides, if you think about the size of that V8 flywheel, thats a LOT of rotational inertia, whereas a lightened 4age flywheel would be 1/4 the size, and if it did ever let go, would do a fraction of the damage seen in the above pics.

I've seen a lightened Rx7 flywheel shit itself, at around 8000rpm, but it was known to have cracks in it beforehand, but the owner didn't think it would be much of a problem.. The pieces of flywheel only cracked the bellhousing, a couple got through and dented the bonnet, but otherwise, it was very fixable.

[pervert]

Then again, you could have 1000 other machined flywheels, that never break. It comes down to the condition of the flywheel, and the quality of machine work.

The Mustang flywheel isn't even machined though...so it doesn't prove anything about lightened flywheels...

[Dr-X]

As long as you get a decent flywheel to start with, get it machined, then crack tested and balanced, I don't see any issues.

...At which stage you're best of having a proper billiet flywheel anyway The point of this thread is that what happened there is what becomes increasingly likely when you machine an old flywheel. To say that a 4age flywheel isnt as likely to cause that kind of damage is just BS, besides which not everyone here modifies weedeater motors like the 4age

But fine, you can go ahead and machine your flywheel down. Not my feet.

[ChaosAD]

Found it!
http://forums.club4ag.com/topic.asp?ARCHIVE=true&TOPIC_ID=74831

BTW after driving an fxgt with a standard bluetop them mine with a silvertop bottem end and exedy 4.?kg flywheel I noticed $&#$% difference in drivability. The extra compression may have something to do with that though

[Adamal]

Is it just me or are the pics in that Club4AG thread not working?

[RS13]

But fine, you can go ahead and machine your flywheel down. Not my feet.

Isn't the flywheel/gearbox on the passenger side in a FWD Toyota? And besides, in a rotary, the flywheel sits just in front of the firewall, too far forward to get your feet anyway.