transmission Explodes! how does this happen?

[Eikon]

First off.. this is not my car. Just a guy I know who's had some bad luck.

RB20det in a S13.

Guy was driving in 3rd gear, and the clutch dropped to the floor. As he passed through an intersection to pull over, he heard a massive explosion under the car. Bit of transmission flew all over the place.

The police responded to a call from a woman 100 yards away in a Ford SUV who had a chunk of metal fly off the pavement under the S13 bounce into the air, fly 100 yards and hit her hood and windshield... shattering the windshield and injuring her head.

Here's the aftermath of the transmission.









Outside of some C4 explosives, does anyone have any ideas on what would have caused this carnage?

Note, if anyone needs a used RB20 transmission, this one is for sale. It includes custom lightweight bellhousing mods!

[Largekid]

wow! I have never seen that before....maybe the gearset locked up on the inside causing the input shaft to freeze in place...which would cause the transmission to spin right off the motor shattering the bellhousing? pretty creative thinking...i'm not even sure if that is possible in itself. wow.....

[srphoenix]

thats pretty impressive.... looks like a pipe bomb

[l0nestar]

... WOW! Was 'a$$ around' involved?

[Shocker]

This is not the car in question.. just another example of what can happen.

[Coolwhip]

first off, HOLY CRAP. Never seen anything like that beyond the horror stories of flywheels giving way and flying through the bell housing, cutting through the firewall, and chopping the feet and ankles off the unexpected!

I doubt the transmission would torque enough to shatter the bell housing since the mount and the shifter both prevent extreme movements in those directions. Since any movement the engine mounts would allow that degree of movement.

Gear box locking up would most likely snap the input shaft or break internal gear box parts.

My guess is that during the install there was some trama to the housing either it was dropped and had a crack or came with damage like that.

Few questions, did the engine have a Flex Plate between the bellhousing the engine block?

I don't recall if the RB20 uses the block to bottom of the bellhousing brackets to stabalize the bell housing like the RB25's?

Was there enough room for the bell housing to torque without hitting the firewall and such?

I don't think that a harmonic problem would cause this, would probably damage input shaft bearing and such.

Damn

[Coolwhip]

considering that the clutch pedal dropped could of been a pressure plate failure?

Where those fingers that are providing 2400lbs of force release causing a similar assplosion as C4?

[Sil240]

Where's his Flywheel??

Did it shatter and fly through the bellhousing???Or is that that Pressure plate all torn to pieces in the pics?I know Drag cars have scatter shields for that.

Your boy is lucky his car isn't FWD......He needs to call up the clutch manufacturer!!!

[Carl H]

im gonna guess that it was a flywheel failure...what happens when you dont torque bolts to spec.

[Coolwhip]

2 tools never to cheap out on, torque wrench and pry bar.

[Eikon]

I don't know where the flywheel or spacer is?

Perhaps the spacer was undamaged and reused to get the car back on the road?

No a$$ was employed in the making of this carnage. Apparently the guy and his girlfriend were just driving down the road... no racing, or screwing around.

[Coolwhip]

if the flywheel is gone, there goes your anwser.

[240z4u]

im gonna guess that it was a flywheel failure...what happens when you dont torque bolts to spec.

Happened to a guy on Hybridz, his bolts kept backing themselves off and it blew apart.

Scary $hit.

Evan

[raremotive]

if the flywheel is gone, there goes your anwser.

+1

I don't think the bellhousing/transmission is at fault... aluminum is more a ductile metal than iron... which iron is notoreous for cracking/fracturing...which completely shatter.. aluminum do crack.. but they can self heal as in stop the crack from growing bigger.

So I vote flywheel failure.

[l0nestar]

Shockers pics scare me..

[Eikon]

So it sounds like the experts agree that the flywheel was most likely the cause.. Due to the shop installing the bolts either too tight or too loose.

I wonder if it was shaved to be lightened and if they might have done a shoddy job of that? I'll ask the owner about it too see what he has to say.

Thanks for all the input guys.. it will be very helpful for him.

[Warped161]

def a an exploded flywheel, and yeah if the flywheel was improperly lightened and out of balance then this would be your end result. Seriously he's lucky to still have feet.

[Coolwhip]

the sounds of a poorly balanced flywheel, eek

[Cjmartz2k]

I'm going to agree with the flywheel exploding theory. Where was this, in Canada?

[AZhitman]

Holy freakin' crap.

I've seen things like this back when I was into musclecars, but damn.

Makes me want to weld some steel plates to the floor of the 'vert!

[Coolwhip]

who wants to buy a shatter sheild?

fo realz! If you read on the clutch boxes some say "failure of this device may cause injury or death" along those lines. At least i know the Exedy twin plates do.

[ItzGenX]

Looks to be a combination of a pressure plate failure and leading into a flywheel explosion. I've heard flywheel bolts come out before and they give a "tink tink" warning before anything bad can happen (because you still have a few more bolts to help hold it, no silent time bomb effect). The bolt should make noise first due to falling straight into the clutch assy making odd noises. On the other hand, when a pressure plate bolt fails or backs out (one time noise, often silent), it causes clutch failure and shortly after, the whole pressure plate begins to expand due to not being fastened at a certain area. This causes the whole assembly to oscillate causing the flywheel to be overcomed by a massive amount of unbalanced centrifugal force and finally explode from it (much like a crazy unbalanced rim going 200mph can cause the rim to explode).

I've had to help investigate one of these failures before on a mitsubishi eclipse friend of mine. His failure was similar, causing great big holes in the hood, firewall, and the pavement. After gathering all his shrapnel and examining each piece, he was thinking his Fidanza flywheel failed. I took a look at the pieces and noticed the Spec pressure plate was stretched more to one side. Almost all the bolts on the flywheel that hold the pressure plate snapped at the thread EXCEPT one. That bolt was found on the ground where the explosion happened. The neighboring bolt to the missing one was stretched outwards, indicating it failed under centrifugal stress due to handling all the load of that section of pressure plate. If the flywheel had failed first, the bolt would have been stretched towards the middle of the flywheel instead.

Best lesson to be learned is, use Loctite, grab the FSM for toque specs, and use a decent torque wrench. Sometimes it can be life or death when a flywheel explodes.

[Sil240]

Damn......

Shocker are those more pics of the same guys car???

I think the flywheel was damaged prior to installation.Or extremely Lightened....That's why I have an Aluminum Flywheel.My flywheel weighs 11lbs.

I used Locktite on my flywheel bolts.

Yeah RB20's have those 2 brackets that connect the Block and the Trans.

[raremotive]

Holy freakin' crap.

I've seen things like this back when I was into musclecars, but damn.

Makes me want to weld some steel plates to the floor of the 'vert!

I'd go with kevlar... good reason why the military uses it.

[BoostFab]

im gonna guess that it was a flywheel failure...what happens when you dont torque bolts to spec.

exactly... torque your s*** down guys!! always use a bit of lock-tite on the bolt.

we need scatter plates under the car. LOL

i hope that woman doesn't sue

[Shocker]

Damn......

Shocker are those more pics of the same guys car???

I think the flywheel was damaged prior to installation.Or extremely Lightened....That's why I have an Aluminum Flywheel.My flywheel weighs 11lbs.

I used Locktite on my flywheel bolts.

Yeah RB20's have those 2 brackets that connect the Block and the Trans.

Different car, pics were posted on supraforums maybe 8 months ago. Not entirely sure reason for failure. My guess was misshifted (3rd to 2nd) with a cracked/badly imbalanced flywheel, or loose flywheel bolts and a similar scenario.

Scary for sure, and could have definitively killed/****ed his legs.

I considered this. http://store.summitracing.com/...w=sku

[raremotive]

I'd go with kevlar... good reason why the military uses it.

[Eikon]

The pics of the red car posted by Shocker are NOT the same car. That's just another example he must have known about.

[Kansei240sx]

Why do you guys think they call it the "fly"wheel.

lol..... Look how that thing separated, my bet goes to the flying wheel of doom.

[Carl H]

just noticed that the pics shocker posted are of an r32 gts-t.i have not used locktite on my flywheel bolts as the fsm does not specify the use...but the threads were cleaned and new bolts cleaned and fitted all torqued to proper spec.