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Old 10-24-2009, 03:53 PM   #1
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Default Turbo rebuilding

I searched.

Twice.

What are the options for rebuilding a turbo? I have heard both sides of the argument for doing it yourself. As far as I can tell the only real risky bit is loosing the balance on the impellers, That right? I have a dsm t25 that will be going in, in a couple of months. And the bearing wobble, that is to say side to side shaft play, seems a bit much for me. If I press it pretty hard to one side and turn it I can make the intake side impeller scrape the inner wall of the housing. However there is no real play in/out. It was bought from a member here and I was told it was running fine when removed. I trust that to be the case, and I presume oil pressure goes some way to hold it centred? In either case, while I don't "need" it for the car to run, seems I should rebuild it now.

So, on the assumption that I am a pro mechanic, and can actually do the job, is it worth attempting? anybody here succeed at it? or should I just take it in for a rebuild to a pro. Trouble is (of course) the rebuild cost's more than paid for it. I did get a pretty good deal though so no complaints if thats the way it has to be.
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Old 10-24-2009, 04:00 PM   #2
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I'm about to rebuild a T25 myself.

There is a good thread on it in the "useful saved posts"...and I can't justify sending it off for 3x the price of a rebuild kit.

I may however pay to get the rotating parts balanced since I not only worry about the balance, but also getting all the carbon build-up off the shaft. I would also like to media blast the turbine and compressor...and any balancing marks I put on there for reassembly will surely be gone after I media blast the pieces.

If I can find a place to just do the balancing and blasting cheaply I'll do that...otherwise I'll take my chances on marking and hope nothing's too dirty.

Having it all apart also means being able to do trick things like cleaning and polishing the compressor housing yourself.
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Old 10-24-2009, 04:01 PM   #3
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There are quite a few that have successfully rebuilt turbo's. If its a cheap turbo I'd try it. Worst case just get a new one.
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Old 10-24-2009, 04:43 PM   #4
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balancing wheels....lol.
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Old 10-24-2009, 04:52 PM   #5
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Quote:
Originally Posted by 18psi View Post
There are quite a few that have successfully rebuilt turbo's. If its a cheap turbo I'd try it. Worst case just get a new one.
my worst fear would having the intake wheel grenade at 120k rpm wondering where all the little bits made it to
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Old 10-24-2009, 05:08 PM   #6
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I just finished rebuilding the T25 for my car this week. There are a couple sticky spots but it wasn't too bad. For marking the turbine shaft/compressor wheel I used an air powered vibra-pen (though an electric one would work). On my T25 there was a small indent at the top next to the nut and I marked in there and at the edge of the hole in the top of the compressor shaft. If you're going to media blast the hotside wheel (which I had to), I'd use a fairly mild abrasive, not something like garnet. For mine I dipped the thing in a carb cleaner solution for a couple days, then GENTLY scraped off as much as I could, then shot it with glass bead, then final cleaned it with fine scotchbrite (white) and brake cleaner. When blasting the wheel I had the entire shaft (especially the bearing areas) taped off with several layers of duct tape. I also used a polishing wheel on the bearing areas to make them as smooth as possible.

I did basically the same thing on the hotside housing to get it clean as well other than wire wheeling it before blasting... just REALLY tape up the openings well, you don't want any left over abrasive in the engine. I didn't blast the CHRA housing because I wasn't confident in getting it taped off well enough and it came clean with just the wire wheel and brakeleen.

There's also a good writeup with pics for rebuilding a T25/T28 in the tech section at www.sr20forum.com
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Old 10-24-2009, 05:28 PM   #7
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Well I am not so much worried about getting it clean, its the bearings I am after. From what I can see looking onto it its actually in pretty good shape as far as build up on the blades. I'll clean it once its apart of course. I think you have talked me into it. As you guys said I cant spend the money on a rebuild when the kit is so cheap. I have been quoted 280-300 for a rebuild and the kits are 45 all day long on ebay. I think I'll do as you did rennkafer (love the S/N, pro A/C VW tech here) and buy one of those little etching things to mark it up.
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Old 10-24-2009, 06:47 PM   #8
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get a good pair of snap ring pliers.
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Old 10-24-2009, 07:49 PM   #9
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Quote:
Originally Posted by Braineack View Post
get a good pair of snap ring pliers.
+10

I learned this lesson from my dsm days. You CAN NOT rely on crappy autozone snap ring pliers to get the job done. They will bend or break, and possibly injure you in the process. It might work once or twice, but it will happen eventually.
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Old 10-24-2009, 07:54 PM   #10
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No worries, I am a pro mechanic and have a few of them (snap-on).
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Old 10-24-2009, 08:10 PM   #11
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I say the balancing is highly over rated. But what do I know...

My turbo has been holding together great and now leaking a bit since i rebuilt it. For 80 bucks, there is no other way to go.

Get good with pick tools. There is a **** sucker of a ring in the hot side that you kinda have to separate and twist in.
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Old 10-25-2009, 08:24 AM   #12
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Quote:
Originally Posted by Braineack View Post
balancing wheels....lol.
Quote:
Originally Posted by wayne_curr View Post
I say the balancing is highly over rated. But what do I know...
This is good to know before taking the plunge.

I'll swing by Sears and get some good pliers before starting.


Blaize:

The one thing I would do is buy a QUALITY rebuild kit. I've heard they can be hit or miss on eBay...and that the good ones (like gpopshop) are all you could ask for.
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Old 10-25-2009, 09:32 PM   #13
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The retainer that Wayne is talking about looks kind of like a spirolock on a piston pin... and it is a total ********** to get out AND back in. I used a couple dental picks I had, they're invaluable.

For snap ring pliers, it's the one that holds the coldside housing on that's the problem. I used a huge pair of Snap-On 90 degree... they have to be 90* to get in under the housing.

I bought my kit from gpopshop... they tried to talk me into getting the 360* bearing but after looking at it I figured the OEM piece was on a car that couldn't have had less than a 100K mile expected lifespan. For over double the price (the 360* bearing and associated bits is another $98... the normal kit is only $88), I didn't think it was worth the trouble for me since I drive the car maybe 5-6k a year tops. YMMV
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Old 10-25-2009, 09:53 PM   #14
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GPOPSHOP?LInl please!
-g-
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Old 10-26-2009, 09:28 AM   #15
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Quote:
Originally Posted by Reverend Greg View Post
GPOPSHOP?LInl please!
-g-
Home

google is your friend
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Old 10-26-2009, 09:54 AM   #16
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It's crazy what you'll find in the useful saved posts section too: https://www.miataturbo.net/forum/t10996/
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Old 11-23-2009, 11:59 AM   #17
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Hi I'm driving 1.6 Miata with Greddy TD05-16G. The turbo is having oil leakage problem and now I'm thinking of rebuilding it. I saw lots of turbo rebuilt kits in various price range in eBay and I have no idea which one suits my needs. Would you give me some suggestions? Thanks!

BTW I found an URL with turbo rebuilt demonstrations that doesn't need balance (Stage Infinity Mitsubishi TD04-13T Turbo Rebuild)

For your information the following are the pics of my turbo:

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Old 11-23-2009, 05:25 PM   #18
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Quote:
Originally Posted by gospeed81 View Post
If I can find a place to just do the balancing and blasting cheaply I'll do that...otherwise I'll take my chances on marking and hope nothing's too dirty.
Rebuilt Turbochargers| Turbocharger Kits| Turbochargers| Salt Lake City, Utah

He will balance the rotating assembly for free if you buy the rebuild kit from him, or $25 if you just send it to him (can't remember if he sells T25 kits). Cleaning coked oil from the shaft and media blasting the wheels is included in the price.

The wheels are individually balanced from Garrett, and some rebuilders may say that is enough, but IMO, balancing the assembly is important on the small, high speed turbos we use. At 130,000rpm a small imperfection on an impeller can cause a enough imbalance to eat up the bearings in no time. That's my take on it.
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Old 11-23-2009, 07:12 PM   #19
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In the end I got really lucky. I am a pro mechanic at a VW dealership and we cleaned out the shop this past week for an upcoming inspection by the Germans. Well I came across 4 diesel turbo's hidden all over the place and I have traded the four of them in with a local turbo rebuilder towards the rebuild of mine. When all is said and done I am paying 115 to have it fully done by them and the rebuild kits over here are 85 so it is a no brainer. On top of that when I took it all in they spotted a crack in the exhaust housing that I hadn't noticed, and they even had a spare good used housing on the shelf. This was a real shock as the eclipse/laser/talon was never sold here in the U.K. Maybe the Mitsu FTO uses the same engine? anyway great result and one less thing to wonder about when I finally fire it up.
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Old 11-23-2009, 11:53 PM   #20
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kill yourself.
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