RS2 Turbo - Naked!

[twoqu]

Thanks!
Just trying to put something back in!
The comp housing has a 95 date. There seems to be two versions of RS2 the 5324 970 7200 and the 5324 988 7200, although I'm not sure what the difference is!
Hopefully I should have all the bits shortly to attempt reassembly including a 360 degree thrust. It won't be a NASA style rebuild. If it lasts longer than the AET hybrid(not long enough to get any carbon on the wheel) I'll be happy!
I will use what I consider to be the best bits from both.

[Tommy200rs]

This is one of three pics I have stolen from Paul N.
This crack originates in exactly the same place.
31-07-06, 07:22 PM

This picture shows some areas where the sharp edges after kkk machining and molding can be smoothened a little bit by just hand grinding with sand paper (or better one). Some areas are really rough after the molding process and not treated at all.

It wont give you much extra horse power but the thermal peak positions may be reduced and the turbo exhaust housing may live a little bit longer.

The same smoothening work with more pro approach can be done with extrude hone too:
http://www.extrudehone.com/auto-oem.html but more expensive.
- the area where the air enters to blade finns can be done slightly wider like allready in the bigger kkk26 housing from older A200 or URQ.

After the flow surface polishing treatment the turbine housing inside out can be thermo coatead with the gray stuff:
http://turbosunleashed.com/shop/index.php?cPath=69

With thease mods it is possible to slightly increase the durability of the turbine housing which spare part price is really expensive.

[twoqu]

Ok!
Below is a pic of the repair kit from those nice people at Melett! It includes all the parts needed to attempt a rebuild. You can just see the 360 degree bearing in the bottom righthand corner. I will take some comparsion shots later.
Now before everyone starts ordering bits up, please think about it!
Whilst I hope I have shown that a turbocharger is a relatively simple piece of engineering, unless you have a known undamaged turbo that you wanted to freshen up, there would be little point in attempting a rebuild. Any mechanical damage would need the attention of a specialist. At the very least you would need very accurate measuring equipment, better than I have really. I can only measure down to 1/100ths of a mm.
The problem lies in the way turbos are rebuilt. In order to recover the various components they are machined. So centre housings are bored larger which means they need greater o/d bearings. Shafts are machined undersize which means that bearings with a smaller i/d are used. It's possible that the grooves that the piston rings sit in have been machined as well and there are different size seals to accomodate that too! I have measured as accurately as possible and by a process of elimination been able to work out that I am on std sizes. This was only possible through the patience of the guy at Melett who gave me the relevant dimensions. In fact I need to revise the shaft diameter. I had rather hurriedly measured it at 9.94mm when in fact it was 9.96mm!
I was starting with a known good hotside. That is to say it was undamaged and was not leaking any oil into the turbine housing. Likewise the coldside form the RS2 showed no sign of lekage (unlike the hotside!). I had been patiently waiting for a good RS2 coldside to become available. So thats why I am attempting this. All I needed from the RS2 turbo was the compressor housing, wheel and seal plate. Although interestingly, I have noticed a slight difference in the centre housings. I explain later!

[twoqu]

Ok, heres the money shot!
The so called 360 degree bearing is on the left. Obviously it has a far greater area than the usual thrust surface of a regular one. It is a direct replacement.
I was concerned that other modification might be necessary. I have heard that Garrett ones were bolted in.

[twoqu]

Another picture from the rear.

[Jamo]

No it's a straight fit, if you look at the weblink i posted it tells you the part number for it as you can't get the 270 bearing as a seperate item.

How hard would it be to change the bearing alone on a new turbo do you reckon?

I have a new RS2 turbo at home.

[twoqu]

No it's a straight fit, if you look at the weblink i posted it tells you the part number for it as you can't get the 270 bearing as a seperate item.

How hard would it be to change the bearing alone on a new turbo do you reckon?

I have a new RS2 turbo at home.

Jamo!
I have already said the one I have is a direct replacement. If you go back and look at the pics you posted you can see that not only is the 360 bearing a different material(sintered iron) but it suspiciously has three holes as well as the holes for the pins. On the Garrett I am sure it was a durability modification to bolt the bearing to the centre housing.

To be perfectly honest, I wouldn't bother. A new turbo is going to give you years of trouble free service so why bother mucking about with it. Should it need a rebuild in due course then its a no brainer!

[Jamo]

Jamo!
I have already said the one I have is a direct replacement. If you go back and look at the pics you posted you can see that not only is the 360 bearing a different material(sintered iron) but it suspiciously has three holes as well as the holes for the pins. On the Garrett I am sure it was a durability modification to bolt the bearing to the centre housing.

To be perfectly honest, I wouldn't bother. A new turbo is going to give you years of trouble free service so why bother mucking about with it. Should it need a rebuild in due course then its a no brainer!

No mate, not pictures i posted a link with all the part numbers of a k26 rebuild kit.

[twoqu]

No mate, not pictures i posted a link with all the part numbers of a k26 rebuild kit.

Effectively I have that rebuilt kit INCLUDING the correct KKK bearing!
Go back to the first page and refresh your memory. You posted some pics of 270vs360 bearings along with an explaination from Turbonetics. As far as I am aware they are talking about Garrett stuff! Hence the differences!
Whilst we are on the subject here is a pic of a K14 with a 360 degree set up!

[twoqu]

Right back to the plot!
Can anyone spot the difference between the RS2 centre housing on the left and the regulat housing on the right?

[twoqu]

And for those as impatient as me, the answer! The RS2 housing has an addittional oil gallery to the rear. Presumably to aid lubrication of the turbine end. The screwdriver indicates the angle. I'll have to see if I think this housing is suitable to use. I was just going to use the other one as it had no history of leaking.
However, I like things to be well lubricated!

[S2central.net]

Thats the RS2 centre housing compared to what other one ?

[twoqu]

Thats the RS2 centre housing compared to what other one ?

Well I guess its a K26 w/cooled one. The p/n etched on inside is 53261500023. Both have the R035885B and 2490 14 designations on the sides. There are other numbers below the core plugs. The K26 one has 0159 whilst the RS2 has 5150. I have also noticed the RS2 one has vertical lines around the circumference before the ridge that the clamps sit on!

[twoqu]

Here is a better shot. Notice the machined ribs just below the flange. Not sure whether this is unique for the RS2 or not!
Paul N! Can you try to compare your two housings!

[porkkis]

AFAIK 988 is an exhange p/n and 970 is for a new one.