building one good stock turbo, with two bad stock turbo's...?
 

My old turbo couldn't take the abuse of running 13psi after 150k miles, so the compressor wheel started rubbing/hitting the inside of it's housing. The angled scratches visible upon removing the TID told me this. :(

So, I found a guy who vouched for a lower mile s4 turbo that he said had very little shaft/end-play and didn't blow oil. Well, it's day two after finishing the install yesterday and I just noticed some nice plume's on greyish/whiteish smoke coming out of my exhaust as it was idling. Since I hadn't noticed it before, I walked around to the back of my car and just watched as thick clouds puffed out and were clearly visible in the bright sunshine. I couldn't believe it. I got in my car and revved it up and to my dismay more smoke. I drove around the block and yes, more smoke... Bad.

So my question is, I have two bad stock turbo's, but they're bad in different ways... Can I disassemble them and make one good turbo? I've never really taken apart a turbo, but if I know it's possible without having to undertake a full rebuild, then I'll do it. What parts should I use from what turbo to make the "good" one?

:icon_tup:

Just rebuild the one you just installed.

Alright, well I guess I'm going to set aside the "new" turbo and save it for a rebuild/upgrade and then just reinstall my old turbo for the time-being. Thanks. :)

Read this then decide what you want to do:

https://www.rx7club.com/attachment.p...chmentid=76207 (Word doc)

i don't think they sell the rebuild kits anymore, maybe Brian@BNR would have some insight on where to get pieces for a rebuild or sell you a kit himself. he said he could piece together a kit for me a while back but i went with a hybrid instead.

they aren't complicated to handle but some pieces like the carbon seal you may want a machine shop to install.

Wow, great link. Thanks NZ. Sounds like a project I might try to undertake here in the near-future. That should definitely be archived...

I guess my main concern when I created this thread was not knowing whether or not the turbo needed to be balanced after swapping pieces etc.

it is archived, durrr....

linked in the FSM link. :)

balancing is ideal but really only necessary for high performance applications and larger compressor wheels, the stock turbo is hardly a performane monster but not balancing it will decrease its lifespan.

haha... What I meant to say was; "That link should be archived--and it's great that it is."

Performance has nothing to do with it. Any turbo has to be rebalanced when any part of the rotating assembly is changed. If you reuse the wheels and shaft, and return everything to exactly the same relative position as before, it doesn't need to be rebalanced.

if you say so.

i would much rather think of it like pulling apart an engine or a gearbox assembly and putting it back together without inspecting or measuring anything. it is just an assumption it was right to begin with. you think the fans never get out of balance? that just because everything is aligned the way it came apart that minor differences won't change anything?

like i said, it will hardly hurt the turbo since the stocker has less mass to spin.

Unless something physically strikes or damages them, then no they will not just get out of balance on their own. Obviously you wouldn't reuse a damaged wheel.

What minor differences? When you only change the bearings and seals you're not changing any part of the rotating assembly. You just have to be very careful when taking it apart and reassembling it. Don't forget that when the assembly is balanced it has to be done as one unit, then marked and pulled apart for reassembly, so the procedure is just the same whether it's rebalanced or not.

Ah, no... An out-of-balance stock turbo will be damaged just as quickly as a big one.

Man im pritty sure that any small difference is going to cause big problems at 100,000+ RPM even if it is a stock turbo

sometimes i think you argue just for the sake of arguing, what does it hurt to have the assembly balanced? nothing.... it can only help.

I've said the same thing once or twice... :hah:

Sometimes I don't care what you think. :) If you have a valid answer to anything I said then share. Quit trying to pick a fight with cliches.

You're absolutely right, it can't hurt anything (except maybe your wallet). It's also entirely possible it will achieve absolutely nothing. It all depends on the condition of the wheels and shaft.

I love you guys, who sells ht-18 rebuild kits these days?

In the doc I posted the author got a rebuild kit from Turbonetics. When I had the older HT18S-BM from my 12AT rebuilt a TO4 kit was used.