Found out why my secondary wasn't making boost - the damn thing wouldn't rotate. Ah, thought I, bearings are shot and the turbine's hit the housing; well I was half right!

When I pulled the assembly off the car I heard a metallic tinkling, turned it over & looked at the manifold - looks like catastrophic failure of the casting sending bits of iron into the turbine to me...I'd say the turbine wasn't too happy about that!

Oh well, '99 spec twins going on in the next few days (when they arrive).

 

Wow, I've never seen a manifold crack like that. Usually there is some kind of erosive wear that leaves the edges smooth and rounded at the cracks, rather than pieces flaking off.

It IS the perfect time for some new turbos, I agree.

 

Have those turbos had the cracks rewelded? Kinda looks to me like they have. Looks like some die grinder marks are evident in an area or 3.

 

I think you're right. That would explain it for sure.

 

As far as I know, they haven't.
I had the turbo's rebuilt back when the engine was rebuilt (an apex seal cracked), but welding of the manifold was not something that was done, or at least I was not aware of this.

I also found one of the studs was missing on the housing when I pulled the turbo's, I don't think this would have caused this through different stress patterns, but who knows?
I do my own work on the car now to stop this type of stuff happening, it might be a pain now and again, but at least I know the work is done right, or I know who to blame.

 

I've just had another look at the manifold, you're right, this has definitely had welding & grinding done on it, the shape of the casting in the precontrol valve area is all wrong & tool marked.

This reinforces my reasoning to do it myself, you know what the hell has been done and what compromises have been made along the way... (I've also had 1100cc secondary injectors put on before that were actually stock 850's, thankfully I didn't push the tuning before I found out, but that's another story!)

 

"I've just had another look at the manifold, you're right, this has definitely had welding & grinding done on it, the shape of the casting in the precontrol valve area is all wrong & tool marked."

"This reinforces my reasoning to do it myself, you know what the hell has been done and what compromises have been made along the way... (I've also had 1100cc secondary injectors put on before that were actually stock 850's, thankfully I didn't push the tuning before I found out, but that's another story!)"

I thought so! The mating area to the engine exhaust manifold should be flat & smooth, even with cracks. You had a few raised areas that looked rough & weren`t ground down completely. Also had some down in the turbo exhaust inlet. Looked like a pretty "quick" cleanup job.

Whoever did it probably figured that the owner would never see it so they just did as little as they had to do & put the turbos back on the car. It amazes me what I see from shops that are supposedly reputable.

I agree with you 100% that I am MORE comfortable doing all of the work myself so at least I KNOW what has been done to the car & why. Takes more of our time to do it because we have to learn how to do things but really, it is a good learning experience & helps us to understand how the cars work so when something breaks, we can fix the problem. Hope you get your car back on the road soon & have fun with it. It will be worth it!

 

Here's the culprit piece of casting & the damage to the turbine - that hit at speed, the ends of the turbine are really chewed up!

 

Ouch!!
Warning folks! Flying debris can be hazardous to your turbine! Eek!

 

Engine is back together again & is running the standard 0.7/0.5/0.7 bar boost pattern!

 

You know, I am more impressed that someone finally knows how to take a picture up close while using the macro function on their camera! But seriously now I want to take off my turbos and see if my manifold is in decent shape or not...