Turbo shaft bolt

Jay92Ty

Jay92Ty

Donating Member
This morning on my way to work I noticed the turbo was making a really weird noise. The normal spooling noise only very aggressive. It's been hot these few days so I though maybe was getting extremely hot but was not the case. I then drove home (8 miles) and as I was driving it was getting worst. Pulled up the hood, removed the filter, put a flashlight and mirror to see inside the turbine and the f####ing center screw was gone. That caused the blade to run against the housing and chipped a few blades. My dammm luck!! :tdown:Just curious, has this ever happend to anyone? Is this a common thing? Time to pull it out and replace the wheel.
 
Slyclone

Slyclone

Well-known member
Re: Turbo shaft bolt

Pull the intercooler, the chewed up little thing is probably resting aganst the tube and fin of intercooler on turbo side.

Has it happened to me? No. I have heard story's of such a thing. But this has not happened to me. There has to be a reason why it backed it self out.... I'm pretty sure its a left hand thread or something. Might want to look into why it could have done that


A buddy of.mine snapped the hot side wheel on his callaway twin turbo alpha. The hot side came down through the exhaust and carved itself out at 100k+rpm. I have a picture of the wheel, its about the size of a quarter. Pretty *$%#ing crazy. I asked him why its so small and he claims for instant boost. But something such a small caliber can cause big damage.
 
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Jay92Ty

Jay92Ty

Donating Member
Re: Turbo shaft bolt

Slyclone said:
Pull the intercooler, the chewed up little thing is probably resting aganst the tube and fin of intercooler on turbo side.

Has it happened to me? No. I have heard story's of such a thing. But this has not happened to me. There has to be a reason why it backed it self out.... I'm pretty sure its a left hand thread or something. Might want to look into why it could have done that. I asked him why its so small and he claims for instant boost. But something such a small caliber can cause big damage.

A buddy of.mine snapped the hot side wheel on his callaway twin turbo alpha. The hot side came down through the exhaust and carved itself out at 100k+rpm. I have a picture of the wheel, its about the size of a quarter. Pretty *$%#ing crazy.
Click to expand...

Wow that's crazy! thx for the reply..I will deffinately give it a good inspection. I would never have imagined that happening...its a locking nut. kinda weird. O'well time ti fix it. Might just end up getting a nice wheel since its coming apart.
 
Slyclone

Slyclone

Well-known member
Re: Turbo shaft bolt

Just a example of how such a small thing can cause big trouble. Do a good inspection of the inner turbo casting as well. I'm sure the hardened turbo shaft bolt did a little ping pong inside. I would drain the intercooler ( assuming a stock garret one) and clean the one side that all the chunked up aluminum fins could be ground up against really well. Just a though. :tup:
 
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Davemc1963

93 Ty Owner
Re: Turbo shaft bolt

If guess you mean the nut. The male thread is the end of the turbine shaft. Not having that nut tight or in your case missing, will allow the whole of the turbine shaft to thrust into the hot side housing. This will also probably allow the turbine oil ring (seal) to puke oil from the centre section to puke oil into the exhaust. I suspect your hot side may be ok, as its the cold side that will have rubbed, but you would have to check.
Also, it only takes a small amount of lost material from the compressor wheel to put a turbo out of balance.
Also ifits a standard turbo, they are normal right hand thread. Later and many aftermarket turbos use L/H threads that normally prevent inertia forces from trying to undo the nut when running, like many wheel hub nuts.
(unless its a LH turbo)
Easiest way (my opinion) is to just remove the centre section and cold side to inspect and go from there.
 
Jay92Ty

Jay92Ty

Donating Member
Re: Turbo shaft bolt

I'm gonna expect the worst and hope for the best. I did happen to look at the wheel ( cold side) and the blades are worn from the edges and 2 of them have small chips ( broken corners). I wont be able to remove it just yet as i only have one hand right now:tdown: The turbo itself I rebuilt last year? cant remember. it was sounding nice and felt strong. I guess i just f'ed up and didn't tighten the screw good enough ? The truck has 128,### and the turbo is stock. I went with a billet wheel this time sine I have to pull it apart. Now its a waiting game till I get my second hand back:lol:
 
andy2060

andy2060

Member
Re: Turbo shaft bolt

the same thing happened to me a couple of times over the years found the nut resting in the air box both times not sure why it happens it destroyed the turbo bearing,seals,impeller housing one of the turbos snapped the shaft in half that was the last stock turbo for me no problems since I upgraded to a rpm turbo
 
Jay92Ty

Jay92Ty

Donating Member
Re: Turbo shaft bolt

andy2060 said:
the same thing happened to me a couple of times over the years found the nut resting in the air box both times not sure why it happens it destroyed the turbo bearing,seals,impeller housing one of the turbos snapped the shaft in half that was the last stock turbo for me no problems since I upgraded to a rpm turbo
Click to expand...

Then I guess I feel a lil better that it hasn't just happen to me:lol: its still blows my mind that it could even happen. From now on I'll check it more often to make sure there's no play, but most of all that the nut is still in place.( might even lock it somehow) I didn't check inside my filter tube but will tonight to see if its resting in there. That would be the best case scenario...and not inside the housing. Thx guys for all the input.:tup:
 
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Davemc1963

93 Ty Owner
Re: Turbo shaft bolt

Hmm, I think you might struggle getting that to re-balance.
Loctite would probably have prevented it, but hindsight is a wonderful thing.
The actual torque value isn't that high. I was given it from a turbo shop, but don't have it to hand because I'm at work atm, but I seem to remember its not a lot.
I suffered a similar failure recently, due to thrust bearing / seal failure. I dont want to go into it here, as the turbo was from someone on here and it lasted just over 100miles! I managed to 'save it' in time, with just a minor rub. But it was an expensive lesson learned and has cost me about $150 for the rebuild kit and rebalance and then the hassle to sort it.
I just got home and thought that I'd add the torque figure I was given for the shaft nut, as when I was trying to find it on the net some time ago, I found all sorts of figures. That said, I cant honestly say this is a Mitsubishi figure, but it is one from a reputable turbo shop and is pretty ball park for the size of thread.
The figure I was given is 12.2Nm. That equates to 107.98lbs/in or 8.99lbs/ft in English.
 
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