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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
Posts: 3,261
This is the reply from my turbo guy. I forgot to tell him turbo was working fine before piece of metal trashed the blades. I emailed him again with that and his reply was has to be internal issue in turbo and basically only measuring everything would tell. Here is his original reply. Regards Alan;

The biggest issue we come across, presuming all internal clearances are correct is the inability of the oil feed into the turbocharger to drain away freely and fast enough. This is either one of two things. 1 too much oil being feed into the turbocharger (excessive oil pressure or volume) or 2 the oil is not able to drain freely from the bearing body drain with out any resistance. (Engine crank case pressure, restricted drain passage) The oil sealing of the K27-7006 is by a piston ring at both the compressor and turbine end of the turbocharger. Both these piston rings run end gaps (normally .003” to .006”) so if there is flooding or pressurisation of the bearing housing then oil will seep out the piston ring gap. If your friend is blocking the oil drain and pressurising the oil feed with oil in it then it will force oil past the ring gap. This is exactly what will happen while on the engine if the drain has any form of restriction including crank case pressure. Being a 930 I would personally be checking the scavenge pump for the turbocharger accumulator bottle that is mounted below the turbocharger. If this scavenge pump is not scavenging enough oil away then this is exactly what can happen.
Once again I can only presume the internal clearances are correct. The K27-7006 is what we call a large component slow turning turbocharger so all cleanses, oil pressure, oil volume; oil drain, oil scavenge, crank case pressure etc need to be correct.
Hope this is of help.
83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 06-05-2017, 06:25 PM
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