I found this site, and I'm really excited about it. I have a list of questions. I have a 90' sunbird with a factory turbo. I'm having some problems with it, and would greatly appreciate any help or advise anyone could offer. The symptoms are these:
-the hose from air filter to turbo inlet has become gummy ( I assume from heat or age) and does not remain clamped on the turbo inlet. Could it be just age? or is my turbo definitely overheating?
-The turbo makes loud noises at certain boost levels
- The compressor blades have a thin black soot like film on them
-When I grab the shaft of the compressor, there is a small bit of up and down play. Can you do anything to reduce that?
My worst fear:
-The turbo bearings are shot, and the blades are damaged and unbalanced, requiring the purchase of a new turbo
My hope:
some soot or dust from unfiltered air has caked on the blades, causing it to be unbalanced, and when I run some seafoam through it, it will clean everything out, and restore balance, and solve my problem. Am I dreaming? Any advise?
Here are questions I have:
1.) What kind of turbo is the factory stock turbo? T3? T4?
2.) What can you use to rebuild/ replace it?
3.) Does the factory turbo have bushings or bearing?
4.) How much shaft play is acceptable on the factory turbo?
5.) How hard is it to rebuild the turbo myself (replace bearings/bushings or whatever)?
6.) what is the full list of components I would need to buy to rebuild it (including gaskets and such)?
7.) Is the car worth repairing, or should I just junk it?
I could be very wrong, but I'm guessing the bushings are well worn and in need of replacement. Is the car burning oil? Also, I believe the stock turbo size is a T25, so if you do need a new turbo, it would be a good idea to go with a T3. There is a way to modify the stock manifold to work with a T3 from what I understand. Hopefully, a turbo 2.0 guru like Ned Southwick (or Scott Ruggles, or Protomec) can help you out in this thread.
<img src=http://ourworld.cs.com/jwithspray/Nitrosig13303.JPG>
I suppose I'm no "guru," but I may be able to help.
1) Gummy. That sounds about right for a vehicle of that age. You've got oil vapor and crankcase blowby gasses floating around in that tube the entire time the engine is running. They'll collect in the bottom of the intake can and all over the inside of the tube, and eventually they'll take a toll on the integrity of the plastic. Mine's "soft" but not as bad as yours, yet. I clean the tube out from time to time, hopefully it won't get worse than "soft."
2) Some up and down play is normal for a used turbo. The bushings in that T25 will wear over time. Hard to say how much is too much if you're just checking by feel, that's something you learn by experience. I'm sure there's a spec, though, somewhere. If you have access to a dial indicator it may be possible to measure the amount of play with the compressor housing installed. FWIW, I've seen some fairly loose turbos work well.
If you're burning oil, check the tube from the turbo to the throttle body for excessive oil. Try taking a short drive with this tube removed. If oil burning stops, you've probably found a turbo in need of a rebuild. I've used an Ebay rebuild kit for a T25 but I haven't installed the turbo yet. But people with far less mechanical experience than I have successfully rebuilt turbos at home, so I don't think I'll have a problem.
FWIW, if the turbo's overheating you won't have black sooty buildup on the compressor fins. Just like on a spark plug, carbon will burn off if it's heated enough. Is this turbo removed from the car? If so you could remove the compressor housing to check the side play in the shaft, and to clean the compressor blades. I've found that alternating Castrol Super Clean or Purple Power and Gasoline as a cleaning solution can do a good job with old, baked oil and carbon deposits. Be sure to use ventilation, gloves, eye protection, biohazard suit etc. Don't pour liguid down the intake tube, and especially not while the engine is running. If you feel the need to try and clean the compressor, use an aerosol and spray your cleaner into the turbo. I'd do it while the engine is idling, using relatively small amounts of spray so excess liquid doesn't build up in the compressor housing. I've found that using a non-clorinated brake parts cleaner that's high in acetone content (CRC green is one brand) will usually give good results.
As far as installing a T3, you need to weld a different flange on the exhaust manifold. But you could try to locate a turbo from a 90-91 Grand Prix Turbo for a larger bolt on replacement.
In my opinion, as someone who already owns a turbo 'bird, I'd say junk it. No matter what you do, that car will never be any good. You'll just keep wanting to up the boost, and improve overall performace, all the while spending time and money on an old car that nobody else seems to appreciate. I'll give you the address to my house... err, to a reputable junkyard, where you can drop it off.
Actually there's a few other 'bird owners on the 2nd gen and 1st gen forums. Have fun.
hth
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