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It wasn't the turbo...


Willens

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I bought a Z somewhat "Sight unseen," as it wasn't really stable to drive it, I was told it had a blown turbo. I bought a rebuild kit, figuring it could use it either way (236XXX miles,) and I got to the turbo. The compressor wheel spins freely, so I'm not thinking that constitutes a fried turbo. Anyways, after a short drive, an outrageous amount of smoke poured out, the engine rattled, ran like complete dogsh!t, and after seeing it get worse during shifts, I come to the diagnosis that is more like head damage. I suspect the valve guides/seats are long gone, and probably anything else tied to the valves. Piston rings are probably gone too. Some testing will tell, but I am very disappointed. This is my first attempt at a turbo build, and my knowledge is not yet there on forced induction. It sounded plausible, based on the vague description, yet in all reality, this is far worse.

 

One last thing: Does anyone have a solution for getting around the locking tabs that flush to the turbo flange nuts? I'm guessing you have to take the manifold off and bend them, because I can barely turn a nut half a rotation, and get one tab to bend. Is there any solution to this, or do I really have to take the manifold off? Sounds like I have to in order to remove the head anyways. It's either a rebuild, or considering an aftermarket performance head. Time will tell, and by time, I really mean money.

 

-Willens

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Hey Willens, it sucks to hear about that. Not a very good start on the 'ol 280ZXT :?

 

If I were in your shoes, I'd do a compression check on the head to see if you get some good #'s across the board before you pull the head or source a replacement. You can probably borrow a compression tester from Autozone...do a dry test, then a wet test. You should be able to get say 130-150 pounds across the board.

 

Just because the turbo shaft spins freely doesn't mean that it isn't shot. You should also check the "axial play" to make sure that it isn't excessive. Also, you could pull the oil drain tube to see if it is blocked...if it is, that could send a majority of the oil right through the turbo the wrong way...

 

Keep us posted...and may the Z-Force be with you!! :icon42:

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Well, the turbo is irrelevant at this point, because some of us know what "valve rattle" sounds like. A common way is running a car with no coolant for too long. Even if it were just the turbo, it wouldn't explain the overall harshness of startup, idle, or even basic engine loads, well under any boost levels. That is what this car experiences. When I get over to the car (it's about 30 minutes away from me, at least,) then I can take a look at compression testing, which I had intended for, and also dreading them, haha

 

...I'll spare a full symposium, but what this car is experiencing is far beyond a shot turbo. I can just hear the valves screaming/rattling when I start the bitch immediately. If a turbo can recreate that same sound, someone let me know. Turbo is new to me, but I wouldn't imagine such a thing...

 

Thank you for your input.

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Yeah, the inlet/intake piping gushed out a good half quart of black sludge/oil, which is stifling. Tell me this isn't common, haha

 

PART 2: Flat top N/A pistons in a turbo application? I believe I noted something about an N/A cam as well (see also: crazy talk.) I may not know turbochargers themselves, but I know cams. As a turbo car would desire more overlap, and not such a "hot" lift, how the !@#$ would this be possible? If so, someone please explain. I am weary of the purchase, but the longblock just underwent a fresh rebuild.

 

I am thankful to be part of what seems to be the best Z forum for anything on the web, with the exception of tt.net for Z32 specifics. :)

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I need to parse my text, yes, and I've had a few beers, so forgive me, but if a turbo is blown, does it make any sound, specifically? I'm waiting for my turbo books to arrive, so I can stop inquiring about what must be rookie technicalities for most of you. My infinite thanks for your patience and understanding.

 

Thanks again,

-Willens

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