Let me start out by saying that I am not exactly new to turbocharging, but I have never actually taken apart a turbo and rebuilt them, and Im looking for advice from people who have.

I am inspecting this new T3/T4 hybrid that I just purchased, and there are a few things I need to have explained.

First up is the compressor housing -





There was / is no seal between the compressor housing. I cannot say for sure, but it looks like there is no seal where the compressor base meets the center section either (circled in red). Common sense tells me that you would think one would be used, so that raised a red flag for me. I started looking at rebuild kits for this model, and in those kits, it seems that they supply seals for these locations.

I am looking for advice / feedback on this, as I said, I have never done this before.

Next up is the internal wastegate -



Again, there is no gasket between these pieces. I would think one would be needed?

Also, notice the port for the wastegate. See how small it is compared to the diameter of the "cap", you can clearly see how much overlap there is. I have heard from another source that porting this will help eliminate boost creep, so Im wondering if that is something else that needs to be done.

Looks like a cheap ebay turbo to me. Your best bet is to buy a rebuild kit and rebuild it yourself to make sure everything is in good shape and get the impellers balanced. There might not be any gaskets required there.
You won't know if its balanced and if the seals and bearings are any good unless you do the work yourself with known high-quality parts. A lot of those ebay turbos are just assembled incorrectly or with inferior parts.

There are no gasket where you are indicating.

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62 Buick Special
86 GT, 5-Speed
87 GT, 3.4l DOHC Turbo 415 WHP, 11.9 @ 118
88 Toyota Supra Turbo

Awesome, thats just what I wanted to hear too

I know its balance as I see material removed from both wheels. Bearings seem fine, zero thrust slop and just a very small amount of side-side play. Dont know about the seals, but I imagine they are fine. My main concern was about the gaskets.

No comments on the wastegate port?

[This message has been edited by AutoTech (edited 04-08-2008).]

Be aware that cheap Chinese copies of the Garrett Turbochargers are now finding their way into the USA. They will differ in design from the originals. Garretts do use a large O ring gasket between both ends of the compresor while they do not use a gasket at the exhaust adapter. It looks like your turbo does not use a Gasket or O ring in either place.
Check the play in the shaft by wiggling it with your fingers. If the wobble is relatively light then the turbo doesn't need rebuilding and exercise care that you don't accidentally bend the compressor wheel. Then assemble it and wiggle the shaft again. If the turbine and compressor wheels do not contact the housing then the turbo should be good to use as is. Remember even a slight bend in the vanes will cause bad vibrations so be careful. .

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87GT - with 3800SC Series III engine, 4T65eHD
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Dennis LaGrua: slight bend in the vanes

Uh oh, we found trouble in paradise...

[This message has been edited by AutoTech (edited 04-08-2008).]

I meant an irregular bend in the vanes. The vanes are normally curved and you could say that they are bent. However they should all look uniform or the compressor wheel is toast.

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87GT - with 3800SC Series III engine, 4T65eHD
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Dennis LaGrua: I meant an irregular bend in the vanes. The vanes are normally curved and you could say that they are bent. However they should all look uniform or the compressor wheel is toast.

I know what you meant, you didnt notice the animation? Click on the thumbnail, they are bent.

Im not sure if this could be the aftermath of bad shipping or not. Apparently the tape he used on the box wasnt strong enough, and the PO had to re-tape it while in transit. Who knows if the turbo fell out of the box and dropped 4ft to the ground because of it. The PO tape that was used says "Received in damaged condition".

Yeah, its damaged alright

[This message has been edited by AutoTech (edited 04-08-2008).]

Was the compressor housing not attached to the turbo when you bought it? Are there marks on the housing from the blades touching?

quote Originally posted by AutoTech: I know what you meant, you didnt notice the animation? Click on the thumbnail, they are bent. Im not sure if this could be the aftermath of bad shipping or not. Apparently the tape he used on the box wasnt strong enough, and the PO had to re-tape it while in transit. Who knows if the turbo fell out of the box and dropped 4ft to the ground because of it. The PO tape that was used says "Received in damaged condition". Yeah, its damaged alright

Wow. Yeah, that's pretty damaged. I've seen some of the gas turbine crap that comes from China, so it would NOT surprise me if it came that way from the factory. Proven time and time again: you get what you pay for.

No, the housing was mounted and there are no marks on the tips or anything. I have no idea how it happened - maybe the mail guy said "oo - whats this" - and pushed a couple fins down while looking at it when/if the turbo fell outta the box. (I still dont like the idea of a turbo falling out the box and slamming into the ground)

Anyway, I have to call them now to get this straightened out (pun intended).

Like I said, cheap ebay turbo. Buy a new one from a reputable turbo dealer.

quote Originally posted by Steven Snyder: Like I said, cheap ebay turbo. Buy a new one from a reputable turbo dealer.

These arent really all that bad. One has been proven to make over 400hp, and has lasted over 30K miles. Another lasting over 70K so far.

It may not be a Garrett or an Turbonetics, but they will work so long as you know how to check them. For example my wheel - that could have happened to anyone. Granted it may happen more often, but thats why you check them. I hear that most problems associated with these are the oil seals. They can only tolerate ~30psi oil pressure. When people install them, they use no oil restrictor at all, then complain it leaks after 1K miles.

Alot of people have used these successfully, but it seems that no matter how many people that have, you only hear about the bad ones. Im not saying that these are as reliable as name-brand, but you cant honestly think that you can just take a $200 turbo and slap it on your car without checking it - and I think thats what most people do.

Don't be so quick to call it cheap junk until you know for sure exactly where it was made and by whom.

First, until you remove the compressor base from the center section and see for yourself, there is a rubber seal sandwhiched between the two parts circled but you will never see it while the base is bolted to the center section. It is rare that I've seen a gasket between the inlet flange or the exhaust flange although they are available. The compressor housing may or may not have a paper O-ring gasket between it and the base. Some of the oil cooled Garrett turbos I've removed from Saabs did not have them neither were they included with the rebuild kits.

Some of the blade run out and possibly all of it is inaccurate, if you look at your illustration again closely you will also notice that the center section oscillates up and down in the picture along with the blades, then you have to take into cosideration the fact that the shaft is floating so merely turning it can change the shafts centric position also it is unusual for several of the blades to be bent in the manner that the picture suggests with no sign of contact marks. It is possible to slightly bend the blades if you are not careful removing or reinstalling the compressor housing or if you put pressure on the blades while handling the exposed compressor wheel.

Back to quality, I called Turbonetics last week to inquire about some turbo parts because I carelessly damaged a good .60 compressor wheel and I was told ~ the following; A new Garrett wheel $70, generic wheel $45 and a new generic center section alone to replace one with a worn bearing bore $55 and that was followed with the statement that the generic parts are of good dependable quality.

That's coming from a big name in the turbo aftermarket so the generics you see may not necessarily be junk at all. XS Power sells turbos for a good price and their turbos received a good recommendation from one of the major muscle car magazine for what that's worth.

Make sure your blades do not touch the compressor housing and that the bearing play does not seem to be to excessive, my new Garrett turbo lateral movement felt like about .020 the bearing clearance will have an effect on oil flow through the turbo, to much and it may out flow the drain and go past the turbine seal into the exhaust.

Thank you Joseph, that is very good information to know. These are the reasons I like the forum, it has a wealth of knowledge.

I was very careful when removing the housing and during the handling of the unit while it was off. There are actually 3 blades that are bent. The tip of the "middle" blade is the worst, and the 2 on either side of it are not as bad - as if someone "pushed" the wheel with the palm of thier hand - making the middle the worst having the most contact, and the others on either side getting only minor contact.