Since my last post, I checked the 617 turbo for boost pressure and play in the compressor wheel. I hooked up a T fitting with a pressure/vaccum gauge to the banjo intake manifold fitting near the firewall. I could not get a positive pressure by racing the engine in park. In fact, there is a slight vacuum as rpms increase. I also did a load test consisting of driving the car and observing the pressure gauge. Again, no positive intake manifold pressure.

I also observed the turbo was spinning when the engine was running. There was very little axial play in the compressor wheel with the engine stopped.

Conclusion: The turbo spins in an apparently normal way, but does not pressurize the intake manifold. I looked at the drawings of the turbo in the 617 engine manual and came up with the following three possible causes of loss of pressure.


1. The pressure regulator valve is stuck open causing all pressure to vent to exhaust

2. There are leaks in the shaft seals that allow the pressure to vent

3. The loss of oil flow to the bearings caused the wheel to rub resulting in larger cleareances between the wheel and the volute body

Does anyone know if there are rebuild kits available for the bearings and shaft seals or do you just by used turbo?

Regards,
The Chief