We thought I'd destroyed my turbo but I might have been wrong.......it looks like the PCV has been stuck in the open position and when on boost I have been pumping 14psi into the crankcase. A turbo dude thinks that it may have not allowed the turbo to return oil to the sump?
What do you think?
The PCV is located in the plenum chamber below the throttle body and allows crankcase gases to be recirculated into the engine and be burnt, it is a one way valve and is supposed to shut on boost.

I think you should replace your PCV valve with one that works! :P

Apart from that, I don't have a clue!! :alien

Your oil pressure feed to your turbo should be well above 14psi, so the oil should flow through the turbo anyway.

It's only if the crankcase pressure gets above the oil supply pressure that you will have a problem and oil won't flow.

Also, if the crankcase is pressurized, it will also pressurize the oil suction, and therefore increase the oil pressure.

I don't see how it could have stopped oil returning from the turbo.

Yeah Wes, I thought that also?.....but say if the return from turbo to sump is near enough to atm, then would not any increase in pressure within the crankcase decrease the return flow and increase the pressure in the return gallery?
Hmmmmm, but yes you would expect suction pressure to increase and therefore discharge as you said (is it the same in a positive displacement pump as a centrif?).......:alien
Bugger it, I'll fire the thing up on Saturday and keep my fingers crossed.
:beer

reckon you wont have a problem.
let us know how much boost you get.

well on my V6 the oil pressure should be 50-70psi @ 3000rpm. 14psi of back pressure wouldn't stop oil from flowing.

but I reckon an oil pump is no different to any other pump. The 50-70psi is the pump head. If the suction pressure is increased by 14psi, then the pump head will remain the same and the discharge pressure will be 64-84psi.

The only thing I would be worried about is blow oil seals, or a problem my mate had with his sprinter where the crankcase pressure would shoot the dipstick out of it's hole.