VNT failure mode?

[CSX321]

My '89 CSX quit making boost, but it runs okay otherwise. I pulled the intake hose off and tried to spin the turbo by hand. It spins about 1/3 of a rotation in either direction, but then it's stopped by something. The compressor wheel looks okay, spins freely before it stops, has no play, and there's no evidence it's hit the housing. Is there a known failure mode like this for a VNT? Or do I have some debris or something in it, maybe on the turbine side?

[zin]

Sounds like what happened to the Spirit. In that case the thrust washer split and allowed the turbine wheel to contact the backing plate and STOP. Upon disassembly, I found the compressor wheel to have just kissed the housing with no apparent damage. Pretty much the same thing on the turbine side, except that wheel contacted the backing plate. Seems the thrust washer failed rather abruptly. I can only guess that a lack of oil was to blame, though nothing was plugged up. Here are a few pictures of what I found, hope it's something less, and not more than what you see here.

Mike

[turbovanman²]

The first pic looks like it got a bit of dirt in it and ground it down, ditto for the 5th and 6th pics.

[tryingbe]

Use K and N much?

[crazymadbastard]

This is inside the turbo, an air filter is not to blame.. If it is a t3 turbine and center section, then the weaker t3 center section failed. My guess is hybrids just suck because of this imbalance. It is a neat idea for the packaging into our engines but may be the compromise.

[Clay]

looks like you were getting thrust in there some how.

[turbovanman²]

This is inside the turbo, an air filter is not to blame.. If it is a t3 turbine and center section, then the weaker t3 center section failed. My guess is hybrids just suck because of this imbalance. It is a neat idea for the packaging into our engines but may be the compromise.

From being on the forums, I have yet to see a rash of hybrid failures? :confused:

Yes, a bad air filter lets dirt into the engine, which will get past the rings and wear the engine from the inside out. Thats why racers don't run air filters because they constantly rebuild there engines so they don't care, ;)

BTW, nothing wrong with K@N filters, propaganda running wild, lol!

[crazymadbastard]

Yes, a bad air filter lets dirt into the engine, which will get past the rings and wear the engine from the inside out. Thats why racers don't run air filters because they constantly rebuild there engines so they don't care, ;)



Nah, they run bareback to help port things out for more powah!

[turbovanman²]

Nah, they run bareback to help port things out for more powah!

Hahhhaa, yeah, extrude honing baby, :lol:

[johnl]

Hey Mike - I, certainly am not an expert, but it looks like oiling failure - presssure or contanimantion. If the oil filter goes into by pass mode, then debris can get to the turbo. Your failure analysis might benefit if you cut the filter open and look to see how clogged or not it is.

[CSX321]

Well, this is just bizarre. My daughter said the CSX suddenly started making boost again on her way home today. I took it out just now and drove it, and sure enough, it seems fine. :confused2: Normal boost, no weird noises, no smoke. :confused2::confused2::confused2: I can only assume there is now some piece of debris either up against the cat or the intercooler inlet. I guess I'll just keep an eye on it and see what happens.

[zin]

Hey Mike - I, certainly am not an expert, but it looks like oiling failure - pressure or contamination. If the oil filter goes into by pass mode, then debris can get to the turbo. Your failure analysis might benefit if you cut the filter open and look to see how clogged or not it is.

This is what I thought too, that or debris. I'm leaning toward the oiling as the turbo still had the sintered bronze filter in-line, and it was not plugged at all. I'm guessing that my oil pump failure was some time in coming and just didn't get noticed. I'd only had the car a week or two when this happened, and still don't know what "normal" is on the oil pressure gauge. Really wish Chryco would have gone to the trouble to actually put numbers on their gauges!!

Good to hear the VNT is working again. If it wasn't for the compressor wheel not moving I'd have bet it was the vanes sticking. Oh well guess we shouldn't look a gift horse in the mouth!

Mike