Sheared turbo shaft...#3

[Okayplayer]

Hey fellas, I have a quick question before I put my rebuilt turbo on my car. Can a bad MBC cause a turbine wheel shaft to shear clean off? What would be the cause? I just want to make sure I'm not doing anything wrong with the turbos. I hope it's just this no-name MBC that is junking my turbos and not the engine, or knock etc... Help me out! /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/mad.gif

 

[GSX_TC]

is your oil feed line clogged?

 

[Okayplayer]

No I have good oil feed, I checked that when the car was running and everything.

 

[pauleyman]

do you have a working bov?

 

[Okayplayer]

BOV is good, no leaks, actuates fine.

 

Check oil pressure at the source of the oil feed and make sure that it is sufficient.

 

[Okayplayer]

I have good oil pressure. I took out the bad turbo and once I got the o2 housing off, the turbine wheel was sitting in it, the bearings were not seized, as a matter of fact the exhaust side bearing fell right out too.

 

[beaner]

What turbo and is the oil drain not stock? Where's the oil feeding from? Installed pics?

 

[Okayplayer]

It was a 14b feeding with a stock line from the head.

 

[4thStroke]

How much boost were you running?

 

[Okayplayer]

I was running 14lbs of boost. What I'm trying to figure out though is would a malfunctioning boost controller do this to a turbo?

 

[pauleyman]

I don't see how a boost controller could cause this. A serious boost leak might but you would also run stupid rich on a mas setup unless you have a blow through setup or are using an SD setup or something.

 

[grocery_getter]

I've seen this happened twice in 15 years. One on a 14B, second one on a garret turbo. Its rare but it happens. The wheel is friction welded to the shaft. When the weld fails, the wheel comes off the shaft. Just your luck.

 

[Launch]

Turbos have a rpm limit guys...

 

[Okayplayer]

But the thing is this is not the first time it's happened. 2 other turbos suffered the same fate. I had a 14b on the car when I bought it and it worked fine. So let me ask this, what happens when a boost controller fails?

 

[CutlassJim]

It doesn't control boost....


I will either

A)Be stuck open in which case you would run waste gate boost or

B)Get stuck closed and you would run infinite boost

I could see option B causing the problem but maybe your motor would blow up first?

 

[thecman02]

A boost controller will either stick closed. Giving you way more then 14psi which you would see with the boost gauge, or you'd get wastegate pressure. If you have a bad boost leak the turbo will blow trying to reach a pressure that it can't reach.

What is the oil pressure at the turbo feed? Unless you have a gauge coming off the head what is at the head can be quite a bit lower then off the oil filter housing or wherever your taking the oil pressure.

 

[Okayplayer]

I'm not sure of the pressure at the head but it is all a stock setup. I am considering running from the ofh again, but I don't want to over pressurize the oil going to the turbo. I know the MHI cartridge has a built in oil restrictor but is that enough?