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K26 tear down and rebuild
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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Tue Jul 05, 2011 6:13 am    Post subject: K26 tear down and rebuild Reply with quote

I looked, but could not find anything specific to our turbos for teardown and rebuild, so here are my pictures as I tear down and rebuild parts from my S1 and S2 turbos and assemble them into one good one. I'm taking the shaft and compressor parts from my S1 and putting it into the center section of the S2 because my center section was broken in several spots on the exhaust side of the center section from over-tightening (guessing it was done by one of the previous owners as it does not look like normal wear at all).

The reason I'm using the S1 turbo is that the compressor wheel is slightly larger. The S2 wheel would spool quicker, but since I have all other S1 components on my car, this makes the most sense to me. Especially since I will be performing some other modifications to quicken up the spool anyway.

Without further adieu...

Remove the compressor wheel nut after first marking the nut, shaft, and wheel for alignment. If you get the wheel misaligned by even a little bit, it could cause the wheel to contact the housing at full RPM/boost, which will not end well. I used an impact on a medium setting with a 6 point 10mm socket and "short blips" of the throttle on the gun and the nut came right off of both turbos.



A small amount of heat will allow the compressor wheel to come right off if it's stuck. Both of my wheels were not budging until heat was applied for about 15-20 seconds. After that they lifted right off.



Once the compressor wheel is out of the way, you can remove the torx retaining bolts under it. Again, medium setting on the impact to not strip anything and short blips. Torx is a T30.




Once that plate is removed, you can pop out the center section that has the sealing rings in it with just your thumb. The sealing rings are like small piston rings...




Noting the orientation of the oil tabs, thrust washer, etc.





The rebuild kit.



Popping up the thrust washer. It was not stuck or pressed in, just sitting there. I just used the screwdriver to lift the front edge.



Sliding off the little spacers and noting their orientation for later assembly.




A couple of taps with the soft face dead blow hammer sets the shaft free.





Note the seals on the exhaust side of the shaft. They are like small piston rings as well.



Next come the bushing retaining snap rings. I didn't have any snap ring pliers small enough, but they come right out with a couple of small screwdrivers. New ones come in the kit, but I didn't want to lose anything just in case, so I was very careful and none escaped me from either turbo.



Exhaust side has them too...



After pulling the snap rings, these pop out with a couple of light taps on the palm of my hand.



There are a couple more snap rings on the inner edge of both bushings as well. Same thing here for removal.



I had to double nut one of the studs on each of my turbos. I wanted to chase all holes and use anti-seize on all nuts/studs upon reassembly.



Parts all organized from the S1 turbo. I used an old baking tray to hold the S2 turbo separately so that I don't get any parts mixed up other than the ones I want to use from each. I'll show you comparison shots of S1 to S2 compressor parts in another post. The exhaust side appears to be the same on both at least initially.

Removing the small "piston rings" from the exhaust side oil seal. Worked it around with a small screwdriver until one end was free, then just slowly went around the shaft with it. Be SURE to clean the grooves out until they are shiny metal! Any soot debris should be removed. Otherwise the new rings will not sit in there like they are supposed to. A piece of one of the old seal rings can be used to dig the soot/carbon out of the ring groves.




As for cleaning the parts, I soaked the entire assembled turbos in non-chlorinated solvent for about 4 or 5 hours before this teardown, using a brush about 2 hours into the soak to break up the big stuff. I'm going to media blast the hardware and exhaust side housing and will coat the hot side parts. You don't want to media blast the center section or innards just in case media would get trapped inside the housing. That would be bad. The bare center section is soaking in the solvent again overnight so that it will be clean for reassembly tomorrow.

Removing the hard soot gunk from the exhaust side cup. Look at all of that crap!!!



ASSEMBLY TIME!!!

I started by inserting the inner snap rings, then sliding the brass colored bushings into place. After first dipping the bushings in fresh oil...




Then put on the outer snap rings



EDITED POST 7-17-2011. DO NOT SAND THE RINGS!!! PLEASE READ THE POST FROM JULY 17th 2011 BELOW as well as this edited next paragraph!!!

Also, when installing the new "piston ring" type oil seals, DO NOT line up the gaps in the rings. Instead, offset the gaps 90 to 180 degrees from each other. Give the oil sealing rings a little oil with your finger. Once you have the exhaust side sealing rings on the shaft in proper position and lubed, slowly press the turbine shaft back into the housing, while at the same time rotating the shaft by hand. Try to get one ring at a time inserted into the bore as to not bind the rings. DO NOT TAP ON THE SHAFT to assemble it!!! This can bind the sealing ring and cause bent sealing rings or worse damage. Wriggle wriggle push push rotate rotate is the best method. The shaft should spin freely, but should not be as loose as it was with worn seals. This is a mistake I made the first time around.

Here, the thrust washer had to have a small amount of clearance grinding to fit.



Spacers in place.



New "piston rings" on the front seal.



Front side oil seals pushed into place in the cold side platter.



Cold side to CHRA pressure seal.



Sitting the platter down without mushing the seal out of place can be a trick. Hold in place with just a couple of dabs of petroleum jelly.



Locktite Blue for the platter bolts.



Series one vs series two wheels. S1 left, S2 right.



S1 wheel installed with S1 platter. It took a bit of heat again to get it to slip easily into place. Lined up the small scratch marks that I made prior to taking it apart so that the balance would remain the same.



Cold side platter to snail seal, lube with a little petroleum jelly.



Sealed up with a couple silica packs until I get done with the cold side/bypass valve refurbishment tomorrow.



I pulled all of the studs from my hot side since they were bolts on the S2 turbo and I like having two chances to remove them with the studs.



Test fitting hot side housing prior to ceramic coating it. New 8mm 1.25 hardened nuts since a couple of mine had questionable threads.



After ceramic coating and baked for an hour to set the coating, reassembled the hot side. NOTE: I did not cover "rebuilding" the bypass valve since all I did was clean and reassemble it. I even had reusable gaskets in there that I touched up with red silicone just to be safe. Otherwise it was just clean, oil, and put it right back in.




I also ceramic coated the oil return casting to protect it from the heat of the turbo housing.



Made sure to use the S1 cold side and took a picture to prove it to myself just in case I panic later, LOL!



THAT'S IT!!! The turbo will go back on the car in the coming days. Check out my build thread for more project updates.
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Last edited by bnoon on Mon Jul 18, 2011 3:01 am; edited 9 times in total
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11351
Location: PacNW

PostPosted: Tue Jul 05, 2011 1:54 pm    Post subject: Reply with quote

Thanks for an excellent post. . .looking forward to more.
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macBdog  



Joined: 16 Aug 2004
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Location: Brisbane, Australia

PostPosted: Tue Jul 05, 2011 3:11 pm    Post subject: Reply with quote

Awesome post, I wish this was around when my S1 turbo blew up the first time, maybe I wouldn't have had to put a V8 in my car!
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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Wed Jul 06, 2011 2:35 am    Post subject: Reply with quote

Rasta Monsta wrote:
Thanks for an excellent post. . .looking forward to more.

It started out just as pictures so that I knew which order things went back on. Then I thought about it a little more after I had the first one torn down. I ended up taking the first few pictures for the how to on the second turbo actually. You can see how the pics are higher numbered and slightly out of order. I took a week of vacation from comp time that I had saved up to work on this car, so you should see some updates every day until it's ready to run. I'll keep the turbo how to stuff here and then update my project log with the other stuff.

macBdog wrote:
Awesome post, I wish this was around when my S1 turbo blew up the first time, maybe I wouldn't have had to put a V8 in my car!

LOL, I have the same temptation, trust me. I've got a 6.0L with LS3 heads just SCREAMING at me from the corner of the garage "Put me in coach!!!"
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Joes924Racer  



Joined: 03 Nov 2002
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Location: Oregon, Denver Colorado native!

PostPosted: Wed Jul 06, 2011 3:02 am    Post subject: Reply with quote

For the general good of all turbo owners wanting to go this route,
I submit a question, whats the availability of the rebuild kits..
Like in the picture.


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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Wed Jul 06, 2011 8:06 am    Post subject: Reply with quote

Joes924Racer wrote:
For the general good of all turbo owners wanting to go this route,
I submit a question, whats the availability of the rebuild kits..
Like in the picture.


Let me Google that for you!

LOL! All I did was Google it and found several hits, including private shops as well as ebay. I can't even remember which shop I got mine from, but as long as the picture matches you should be OK. The K26 and 27 use the same rebuild kit for sure, but the 28 may also be the same (I can't confirm that).

Also edited first post with the start of the reassembly.
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bnoon  



Joined: 12 Oct 2009
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Location: West Des Moines, IA USA

PostPosted: Wed Jul 06, 2011 11:30 am    Post subject: Reply with quote

Added more assembly pics.
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stevekat  



Joined: 19 Jan 2008
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Location: Los Angeles, CA

PostPosted: Wed Jul 06, 2011 4:05 pm    Post subject: Reply with quote

Nice write up and photos!

When you are sanding that 'piston ring', do you have to get a certain gap or just until the shaft runs freely. Are you concerned that when heated thru normal operation something could change dimension and bind?
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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Wed Jul 06, 2011 11:53 pm    Post subject: Reply with quote

stevekat wrote:
Nice write up and photos!

When you are sanding that 'piston ring', do you have to get a certain gap or just until the shaft runs freely. Are you concerned that when heated thru normal operation something could change dimension and bind?


When I sand the rings, it's the top and bottom that I sanded so that they could expand and compress freely within the groove on the shaft. When I first installed them into the groove, it was very hard to compress them down to get into the bore and the shaft would not turn hardly at all because the rings were binding. The tips there are to CLEAN CLEAN CLEAN the ring groove first, but if they still bind, sand the top and bottom of each ring a little bit until they operate freely within the groove.

The gaps were fine and did not need anything done to them, confirmed by measuring the used rings in the bore, then the new ones, the gap was the same.

Perhaps I can mock up a picture of that process today with an old ring and the other turbine shaft.
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Joes924Racer  



Joined: 03 Nov 2002
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Location: Oregon, Denver Colorado native!

PostPosted: Thu Jul 07, 2011 8:11 am    Post subject: Reply with quote

bnoon hats off to ya you desrve the A+ onv this one ....
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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Thu Jul 07, 2011 10:39 am    Post subject: Reply with quote

Joes924Racer wrote:
bnoon hats off to ya you desrve the A+ onv this one ....


Thanks Bro Joe. I appreciate it. I was looking for a how to when I started planning my rebuild but couldn't find one. Figured we could probably use it.

Updated and finished the original post. Hope you all enjoy. If there are any more questions, ask away.
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bnoon  



Joined: 12 Oct 2009
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Location: West Des Moines, IA USA

PostPosted: Sun Jul 10, 2011 11:47 pm    Post subject: Reply with quote

If you're following my project log, you'll see that the turbo rebuilt here leaks oil out the exhaust side. I must have boogered the shaft oil seals. I had some trouble getting them to seat without binding, so that's got to be it. I'll call some turbo rebuild places for tips and report back with pics.
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joe b  



Joined: 16 Sep 2010
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PostPosted: Wed Jul 13, 2011 10:43 pm    Post subject: Reply with quote

Mine's still in pieces, but I remember going through all of this junk!

I hope mine doesn't leak... if so... it looks like maybe the flange on the WRX turbos could be easily modified to fit the 924 exhaust!
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bnoon  



Joined: 12 Oct 2009
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Location: West Des Moines, IA USA

PostPosted: Mon Jul 18, 2011 2:38 am    Post subject: Reply with quote

Well, I got the turbo torn down yesterday and noticed that the exhaust side oil seal rings had loosened up quite a bit from how I had initially set them up. I called several shops last week and they all told me the same thing: "You don't want it as loose as you had it." When I mentioned how I had to lightly sand down the rings to get them to fit freely, they said that I must not have gotten out all of the carbon buildup from the ring grove, so that's where I concentrated my efforts.

I pulled the old rings out of the groove, then mounted the turbine shaft into my cordless 18V drill. I snapped off a 1/2" or so long piece of one of the old rings, straightened it out a bit, and held it in the tips of a pair of locking pliers. I spun the drill/shaft and used the square end of the straightened ring (the squared edge from the factory ring gap end) to dig out the carbon buildup from the slot. After a few minutes, it was looking pretty good, so I trial fitted the new rings. They slipped in with no sanding, which is good because they measured the same thickness as the other ones did prior to me sanding them, so I confirmed that I had made a mistake during the first rebuild. I'm going to edit my post above to reflect the importance of cleaning that groove out better and NO SANDING the sealing rings!

Also, make sure to look into my project log in the coming days. I have a nice little turbocharger modification to perform during reassembly this time that I won't include here since it's not directly related to the rebuild.
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Carrera RSR  



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PostPosted: Mon Jan 14, 2013 8:15 pm    Post subject: Reply with quote

BROKEN PIC LINKS !!!!!
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