Holset H1C turbo shaft jamming

[Nigelk]

Hi all,
I live in Vanuatu with little specialist Marine advice and service available.
I have a Caribbean(Bertram 32) with twin Cummins 6BT 210 with Holset H1C turbos Around 18 months ago one engine started pouring black smoke, hole right through heat shield of the turbo core assembly. To cut a long story short the whole turbo was replaced bit by bit with genuine Holset parts. Ran fine for 6 moths then after sitting for a month without running, it again poured black smoke on applying power. Took the air cleaner off and found the turbine to be jammed but managed to free it up and the engine ran fine for another 20 hours. I then left it fir 3weeks with out running and again found the turbine to contacting the housing and preventing it spinning. I manually freed it up and again it works fine.
I understand it is normal to have some lateral play to allow the shaft to float in oil. However if I press the turbine forward I can make it jam against the housing but if pressed backwards it will not contact the housing. This suggests yo me the turbine us not centred properly in the housing.
Appreciate any advice on how to sort this out.
Cheers?

 

[jleonard]

http://myholsetturbo.com/manuals/H1C_D_E_H2A.pdf

Above is a link to the Holset repair manual.
Sounds to me like the thrust bearing is shot ad needs replacing. These turbos are easy to rebuild and the kit is about $100 in the US.
Don't know what it would cost for you.
I have rebuilt a few of these and as long as you mark the orientation of the nut when you remove the compressor wheel the balance should stay ok.
When you do rebuild make sure you find out the reason this one failed. Perhaps it is not getting enough oil? Or is salt water getting in?
Hope this helps.

 

[kapnd]

Very likely that poor exhaust system geometry is allowing seawater to run back to the turbo and beyond after the engine is shut down.
In time, the engine will ingest water through an open exhaust valve and hydro lock.
Visit Seaboard Marines website for some really good info re exhaust system design.