Oil pressure problem Io-320. PA30

[Bryan Rose]

Started having problems with my left engine feathering the prop on roll out recently, which also kills the engine.

I noticed that the prop starts feathering below 800 RPM. I then noticed that when I slowed the engine to 800 RPM, the oil pressure is dropping to the top of the red. Increase RPM to max and pressure goes back up, but only to top of the yellow. OK, feathering issue resolved, now what's up with the oil pressure?

On startup, run up, and cruise the pressure is in the green, oil temp is green.

I removed the pressure relief spring today, it looks to be in good working order, marks on the ball bearing indicate it is sealing all the way around.

I saw Frank's issue with the cage being broken. I'll look for that tomorrow.

Any other suggestions?

[Kristin Winter]

If it is not the oil pressure relief, it is either that the pump is not pumping enough, or there is not enough resistance down stream. How much time is on this engine and when was it last overhauled? There was an AD on the oil pump gears that I think was back in the 90's.

You might want to bounce this one off Charlie Melot.