The more I thought about it, the more I decided running a totally `unknown` Turbo wasn`t really the best idea I`ve ever had… Bought a `service kit with all the bearings / seals, read & printed out several very detailed rebuild guides. Set my work area out and made a start.
For info it is a TD04-HL16T Turbo from a Volvo V70, cost a whole £60 🙂
The housings removed
Compressor wheel wasn`t too bad. I marked the shaft, wheel and nut with a light scratch visible on this pic. Enough to be visible, but not enough to gouge material out of the wheel and add stress points. When done, I rubbed over the scratch with some 2000grit W&D to remove any high points (there was a small one on the compressor) The scratch on the Turbine next to the housing looks bad, but it`s not deep, just shiny through all the black shite.
Turbine wheel a bit caked
Sprayed degreaser into the bearing housing. There was a LOT of carbonated oil in there.
Cleaning the compressor wheel
There is supposed to be a slot in this…
Cleaned out all the burned oil. Took a while, but worth it ! The ring snapped in much better after doing this.
CHRA oilways all cleaned, blown through and degreased again
Reassembly was pretty much a case of following the guides and taking my time. Making sure everything went together properly. Only slight issue was tightening the left hand compressor nut. It`s a tiny thing, very low torque and easy to shear.
A couple of times, when it was nipped, the marks didn`t align properly so it needed loosening and redoing. No biggie, but I wanted to make sure it was RIGHT.
After rebuilding and ensuring everything was properly lubricated, the blades were very stiff to spin. I wasn`t sure if I`d done something wrong, but was certain I hadnt. The first time I started the car and the oil pressurised in the journals, it span freely. When I stopped the engine, it still spins really freely. I suspect it just needed a proper oil supply and from then on it`s been perfect.
No smoke on startup or any other tell-tale signs of a worn turbo. There wasn`t much play in the bearings before I started, but when I checked yesterday (June 2014), there is still almost none at all