That's. Huge WTF right there. I've never seen that happen before

 

That sucks man, WTF right? Well I also remember that thread and might have to do some quick searching on the subject. IF I still even have that brace laying around somewhere......it might be going back in. The brace never bothered me much, just seemed pointless. Maybe its not......

 

Never see the shaft shear like that...consider yourself lucky that the screws/rivets didn't fail and made their way in the engine!

 

From Emilio's blog

Behind the wheel: broken throttle shaft

 

Broken throttle shafts are quite common. Stock or modified engine, brace or no brace, N/A or F/I.. no discrimination. The only common denominator is frequent use at 7000rpm.

MX-5 Miata Forum - Throttle shaft breakage

 

then he could be cool like me:

 

to me, it looks like a flaw, the way it snapped.

 

Ya think?

 

edit: I should read the thread next time.

So, what's the fix? I'm down for the preventative mod.

 

Sell me your car for a dollar man thats the fix.

 

There's a shop in Arizona that will put a billet 12mm shaft in a stock throttle body. They want $300+ for it, but that's cheaper than rebuilding a $3000 built longblock because you sucked a piece of crap through it.

edit: Just found his email. $350-400 for a one-off, plus $75 core charge. 3-day turnaround. The shop is British Car Service in Tuscon, AZ, and the guy's name is Ryal Greenwood.

 

micropolish the hole and threads on the shaft to stress relieve them. if it's a recurrent 7k rpm abuse that causes the failure, it's vibration-induced fatigue probably from a manufacturing defect, not a material defect. just remove the stress risers and it'll be much better.

 

That brace doesn't do ****. I put 200,000 miles on my miata without it, never a problem, and I had also milled down that rod through the butterfly. I've put another 200,000 combined on 3 other Miatas I've owned with that brace removed and never any problem.

 

You know, emilio has broken like four of those. It's all over in the power mods section on mnet..