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Discussion Starter #1 (Edited)
How to rebuild your IHI RHB5 VJ11 can be found here:

So you've noticed that your car smokes at idle, smokes at stoplights, smokes on the highway. The first thing to do is to remove the fitting on the inlet side of the compressor and check for play (movement) in the turbine. You want to wiggle the turbine up and down, left and right, and forward and backward. DO NOT FORCE the turbine in any direction. You are merely checking for shaft play as well as end play and there is no need to force anything and possibly make it worse.

First a view of the compressor side thrust bearing and collar:

This is the first step in keeping oil in the center cartridge rather than in your intake piping and eventually into your intake manifold/engine.

Notice that the thrust bearing sits over the collar:

Next step is the seal plate with the piston and two oil seals:

These two oil seals are what stops oil from sliming your piping on tyhe intake side of the turbo.

The whole assembly then gets installed in the seal plate and installed in the center cartridge:

Like so:

This is the first step (and easiest fix) in solving why your GT might be smoking. If you find excessive oil in the intercooler piping, you can probably bet there the oil seals are shot and can be replaced without having to send the turbine in for balancing. Simply mark the compressor wheel and turbine, take the nut off, pull the seal plate, replace seals, and reinstall. This is IF the piston and mating ring are still in good condition, which this one is not:

Here is a bad mating ring (collar):

So long as everything is in good shape, fixing the compressor oil seals is relatively painless.

BUT, this might not be your problem either.

27,927 Posts
Discussion Starter #2 (Edited)
Additional info can be found here:

There is always the possibility, and probably IS the reason, the turbine itself is bad.

Here is a picture of a brand new turbine that was dropped on the ground (yes they are that fragile) and was out of balance:

This is what good ring lands look like. Notice that everything is uniform and that all of the edges are flat and appear to be true.

Now look at this one and notice the difference?:

Notice that the edges have rounded and that this gives greater tolerance for movement of the turbines oil seal. In essense making it very easy for oil to leak, end up burning in the turbine housing, and out of your exhaust piping.\

Notice there is quite a difference between the first turbine (A) and these two pictures (B) (same turbine):

Here is what the turbine oil seal looks like:

It lives here:


27,927 Posts
Discussion Starter #3 (Edited)
The turbines oil seal is meant to rest in the ring land without rubbing either side. The purpose of the section closest to the compressor is to rest/spin against the bearing. Once things start to come out of balance, the turbines shaft/the turbo in general is subject to radial, axial/end play:

Once this happens, there is a good chance your turbine is either completely shot, or needs to be repaired by a reputable turbo shop. Just an FYI that repairing turbines tends to get pretty expensive due to what is involved and the ffort that it takes to repair them. In many cases, it's better/easier/more adventageous to just buy a new shaft...or one that doesn't need this effort to begin with.

The shop that I am currently dealing with/working at/with, can do repairs on any turbine but they will tell you the same as I have told you.

Here are some pictures of what can happen on a bad turbine/balance. FYI- this turbo boosted fine and made no smoke whatsoever. It simply felt different than it had when I first installed it. At the time of install, it was marked as being balanced (but it wasn't) and was a brand new condition turbine:

It was wobbling so much that it cut the backside off the inducer/exducer:

The bearings were also from what was thought to be a reputable seller as well:

My OE Mazda bearings had 145K on them I finally rebuild the turbo and they looked nothing like these new ones that were only a month or so old. The bottom line is that you get what you pay for and when you decide to go cheap and order from a seller on eBay, you get shltty parts, and get shlt on.

Another FYI is that the turbo that I rebuilt more than a year ago is working fine, making no smoke, boosting up to 16 psi with no signs of it dying any time soon.

27,927 Posts
Discussion Starter #4 (Edited)
Unfortunately, there is only one way to find out if your turbine is to blame for your smoking. And you guessed it, you HAVE to take your turbo apart. So long as you have no detectable play, and your compressor wheel hasn't rubbed the housing:

It should in theory be okay to seperate the center cartridge from the exhaust housing:

Mark the turbine, compressor wheel, and compressor nut all in a straight line for reassembly later on:

BUT, this is assuming that your turbo 1) hasn't been rebuilt before and wasn't put back together balanced but managed to last due to luck 2) Is still in good enough shape to continue boosting for miles to come. It is pertinant that you at least mark the turbine, compressor and nut if you plan on doing a basic/ cross your fingers rebuild. Just because an old turbine has been balanced and has been working in your car doesn't mean that it will still be balanced when you put it together again. In actuallity, the only thing keeping it balanced could be the fact that the compressor nut hasn't moved in years and all parts have worn equally, get what I mean?

27,927 Posts
Discussion Starter #5 (Edited)
Your next move would be to visually inspect the turbines ring lands to see if you can detect any wear. If your car is already smoking and you don't have much oil slime on the compressor side, there is a good hance that your oil seal and probably your turbine is shot. :(

Here is my old 145K turbine, I took out the center cartridge but left everything intact when I built my first T Bird. I used this center section as a back up in case anything happened to my T Bird. I'm lucky I kept it because the T Bird lasted only a couple months and a dyno session before I had to swap my old one back in. My 145K turbo lasted almost another year untill it blew on the way to a meet in Lake Elsinore. Anyways:

Doesn't look too bad right?

Guess again:

Look furthest left before you get to the turbine, that little notch isn't supposed to be there, it's where the oil seal wore against the ring land :lol:

Here is a better picture of what I mean:

See that second line, the one I drew the arrow to?

Well the oil seal sits in that crevice but shouldn't touch the sides when the turbine spins. It's meant to hold oil back not spin with the turbine. The oil seal itself is quite larger than the actual ring land/shaft that it sits in:

Here is the best picture for an example:

Here you can clearly see how it wears and allows oil to slip past. The oil seal is allowed to wobble all over the place instead of staying stationary within the confines it is supposed to.

Here is the back side of the oil seal that belongs to this turbine:

Now here is the side that wore against the backside of the turbine:

That isn't solely carbon build up on the outer edges, it actually concave from wear :lol:

Here is a better picture of it:

Notice how is is larger than where it sits. This is to allow you to move the oil seal over the first and second section without distorting the seal:

A better picture of how it sits:

Not entirely, I left part of it out so you can see the wear ^

Here is how it actually sits:

Notice how much tolerance there is between where it's supposed to sit and where it actually can be moved. With a good turbine and a new oil seal, it is a tight fit with very little tolerance for movement.

So, what have we learned?

1) If your car is already smoking, you have good compression, your oil seals in the head are good, then you're going to be breaking apart the turbo.

2) If it's already smoking anyways, you're going to need to break it apart regardless if you want to or not. Or buy another turbo, that might smoke in a month or so. In this case, good luck getting your money back for a used item.

3) Get all of your parts before you start. If you're anticipating your turbine to be in good condition, be prepared for it not to be.

4) If you're planning on doing just a basic job, be prepared for basic results.

5) it can be done provided that all parts are in good working condition

6) Don't be scared, it isn't as hard as it looks.

7) Just do it

8) You'll be glad you did.

9) I deserve karma

10) I deserve karma

Alright enough numbers :lol:

Seriously though. If you've gotten this far, you either care enough about your car or want to learn something new, hopefully both. If you aren't planning on going to full rebuild route, order the two oil seals that go on the piston on the compressor side and the oil seal on the turbine, cross your fingers, and hope for the best.

Good Luck and Happy Boosting!:jump:

27,927 Posts
Another quick note about checking for shaft play:

You can reach inside the compressor housing and feel the turbine nut at the compressor wheel. This isn't all that accurate a test of play in the bearings/shaft. If you'd like to test without completely disassembling, take off your exhaust elbow and feel for play on the turbine side as well as the compressor side at the same time. Also, this should be done when the car hasn't been driven as oil in the center cartridge takes up any clearance between the turbine shaft and it's bearings.

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