Stiff compressor wheel?

[karbon]

Today I removed the intake pipe on the inlet side of the compressor to do some work on my shifter cables and not thinking anything of it, tried to spin the compressor wheel with my finger to check the free spin. It was difficult to move, but with a fair amount of force it moved. However, previous times it moved readily with minimal force. I started the car, and the wheel moved very slowly and even stopped a few times at idle until the oil got up to temperature and let it spin freely. Mind that it was about 55 degrees high here and the car was sitting for about 24 hours without having been driven. I was wondering if it's normal for the turbo to kind of sieze like this when the oil is cold and/or the car sits. I have an AGP T3T4 so obviously it has std. bearings. Not sure whether this is an early sign of something to worry about, or other things I should check (no shaft play that I can tell either). Spooling seems fine as always (although slower), and it runs just as strong as it always has. Maybe I'm just being paranoid.

 

[blackGSX2g]

I had a 16g on my old 7-bolt that did that...not exactly the same symptomes, but it would be difficult to spin one time I checked it, then another time it was fine. I sent out to be checked and the bearings ended up being scored. I guess something bad in my oil cycled through it. Might not be the same case as it was over the summer and never really got that cold.

 

[karbon]

Once the oil was heated up it spun like usual, especially with the car off. I changed the oil too just to be sure. One day when I'm feeling bored I may want to check the bearing surfaces out. This is my first DSM and first turbo car so everything like this is a new and sometimes frightening experience. Thanks for the reply.

 

[karbon]

First warm day we had in months so I can do a nice leak test. Take off the intake pipe about 10 minutes after stopping the car, and I find that the compressor wheel will not spin by hand. Has anyone else had a problem with this? Obviously the oil was still warm when I tried to spin it. At idle the wheel will spin a little, slow down and stop, then get going again. If I give it any throttle, it begins spinning. I'm starting to suspct this is what blackGSX experienced with the bearings being scored somehow, but I want others to chime in on this. If all I need is a new bearing, can anyone recommend a place to get a new one and is the process very difficult for the rebuild? Help!

 

[Omega]

If the bushing is shot then chances are, the shaft is gone too. Time for a new turbo or a rebuild.

Ouch.. I just checked your profile. Contact AGP and see what they say. I will bet they will want you to send it in.

 

[Tallen]

...Wow. No guesses guys (See rule #3), your just infecting this forum with junk.
Does the turbo have any shaft play beyond the normal journal bearing play? Does the compressor wheel hit the compressor housing when moved? Anything that may lead you to think something may be wrong aside from this?

Is it turbo timed? Turbo timers are grossly un-necessary for any watercooeld turbo, but I imagine this AGP is oil cooled, so you may want to let it time a little longer. Chances are that the turbo cooling down caused this, whether it be spinning down with no oil pressure or just the reduction in the size of the metals in the turbo caused by cooling. As long as no other symptom of a bad turbo are happening as well, all should be fine.

Did you happen to just change your oil?

 

[Omega]

So your saying that it is normal for the turbine to not spin when the engine is running?

I see what you are saying with the rates of thermal expansion between the different metals in there, but to the point it doesn't spin?

If it isn't the bushing, what could it be?

 

[karbon]

Does the turbo have any shaft play beyond the normal journal bearing play?

Nope, that's what puzzles me, or else I'd be crying about needing new bearings/new turbo.

Does the compressor wheel hit the compressor housing when moved?

Nope, and no whistling or howling under boost like I've read people associate this with.

Anything that may lead you to think something may be wrong aside from this?

The main thing that leads me to believe something is wrong is that it never did this before. Sometime between the end of this summer and the date of the first post here, it's been doing this. Otherwise it spun very freely when pushing it with a finger.

Is it turbo timed? Turbo timers are grossly un-necessary for any watercooeld turbo, but I imagine this AGP is oil cooled, so you may want to let it time a little longer.

Yes I have a turbo timer, but I follow the consensus on turbo timing: unless you were using the turbo up until you parked in the driveway, you're fine as long as you don't get on the boost for the remaining few minutes up to your destination. The turbo always has at least 3 minutes to cool down whether on the way there, or when I stop.

Did you happen to just change your oil?

I changed it about 800 miles ago.

Contact AGP and see what they say. I will bet they will want you to send it in.

Ben at AGP Turbo said that since I have no abnormal shaft play, that it's most likely the shaft that was scored from some contaminant in the oil. I didn't buy the car this way, I've kept oil in it and changed it at regular intervals, and only put Mobil 1 FS 10W30 in it combined with a Mobil 1 filter. The oil line to the turbo is sourced from the oil housing. I'm not sure how some kind of contaminant could've gotten in, but I'm sure stranger things have happened.
Thanks for the help. I'll try to answer any questions as they're posed. Boy do I NOT want to crack the turbo open to inspect the shaft.

 

[Tallen]

Crazy, it looks like you did everything by the book. But you know what, shit does happen, and I think it happened to you. Hopefully AGP can help you out, they seem to be a very kind to others.