Poor quality fuel can cause immense damage to a turbocharger. Incompletely combusted particles from the diesel engine can chip pieces from the blades and often bend them. The "blasting" effect of these dirt particles causes erosion while the high sulphur/water content of the fuel causes corrosion. Foreign objects passing through the nozzle ring also cause damage (pieces of broken valve/piston ring etc.).  

A turbocharger rotor damaged in such a way will cause significant loss of charge pressure and consequent loss of engine performance, out of all proportion to the extent of the damage to the blades.

SDS is often able to repair damaged rotor blades. This is a specialized procedure carried out by highly qualified technicians operating in accordance with class approval.

The rotor blades are dismantled, cleaned ultrasonically and accurately measured. An UV inspection is then carried out to determine whether there are any fractures present. New ones replace fractured blades.

Under certain strictly controlled conditions, welding using a procedure developed through extensive research by metallurgists and PJ Diesel engineers can repair the rotor blades. The method used is TIG (Tungsten Inert Gas) welding: a technique using a non-fusing electrode at low amperage shielded by an inert gas. Only a small zone may be exposed to heating, and the operation must be carried out in a closed welding chamber, free from dirt particles and air turbulence, as any draught will disperse the shielding gas, resulting in a poor welding result.

Following repair the blade is machined and ground back into its original shape and inspected for cracks using UV/penetrant inspection and the weight is then checked. In order to achieve the correct weight distribution, a computer is used to determine the sequence in which the blades should be mounted on the rotor, which is then ready for balancing.

It is often faster to repair turbine blades by welding and further more economically feasible than supplying new ones.

Repairs on turbine rotors in not conducted by many shops, most turbine wheels are scrapped. We have however had great success in rebuilding, and machining units with significant savings for the end users.