Evaluation of failed Holset HX35

[w1ngs]

So I picked up a Holset HX35W at the local scrap yard for $5.00 this week.

The bearings have failed and worn beyond spec though the thrust bearing is not so bad-off.

The real problem though is that the compressor wheel has contacted the housing. The edges of the vanes have been worn by this contact and thus that would have to be replaced.

What I want to determine is: how much of this sort of contact can the housing handle before it's not useable? The surface of the housing isn't very badly marred but a mild denting effect is visible from the wheel bouncing and gyrating against the it. A burnish with steel wool or fine sandpaper would produce a smooth surface albeit with a very small amount more tolerance between it and the compressor wheel.

I can produce macro photographs of the damage later on so all can see.

No biggie if this is not worth using but I would really like to be able to use it if possible.

Cheers!

 

[T9 man]

Well for only $5.00 spent it is well worth buying and asking the question.
Holset units are very well made and you may be lucky with regards to repairable damage to the turbo. I think you can buy rebuild kits for these so it might be worth having a look around. A slightly larger Compressor wheel can be used then have the chamber machined to suit, this is one way of getting the tolerances back and a little bit more oomph. I am pretty sure that with some investigative work and some help from a machinist it just might be possible to rebuild it. Without really good pictures it is very hard for me to say. Hopefully somebody with more experience will see this thread and offer you more advice on the correct path to to take.

Good luck

 

[w1ngs]

Hey, thanks for the advice.

I did find on the internet that rebuild kits and parts for these are available. I could easily replace the compressor and turbine and bearings and have a unit that works; of this I'm sure. Just that the blade contact induced marring of the machined aluminum surface in the compressor housing concerns me in terms of how much metal can be lost before efficiency suffers drastically.

I have, at my disposal, both lathe and mill which would allow me to easily produce a new working surface for the inducer of a larger wheel but I would assume that such a process would be significantly less cost-effective than fitting a stock wheel if possible.

I attempted to check the tolerance of the bearing races in the CHRA and would say there's about .005" against the existing bearings at worst. This implies to me that the bearings would have stopped turning in the CHRA and given all frictional load to the turbine shaft side (the play between bearing and shaft is above the specified 0.020" limit in the service manual).

As for balancing, would I be correct in assuming that a new turbine/compressor set would need to be balanced on a per-unit basis? Or do these come balanced as sets, or even better, individual units? If so I would also assume that there are shops local to me that can perform balancing operations.

Thanks in advance to any and all who reply!

 

[T9 man]

Unable to help you with the balancing question I'm afraid, hopefully someone more familiar with the setup will be along in a while to assist you!

 

[SLEEPER]

before you get too involved you need the full spec of the turbo as there were many variants.