I've had a continual oil leak problem and suspect this might be much of the cause as I had it happen once on a 924 Porsche. On it the vent went directly into the sump cavity and I couldn't get the fitting out of the block so after draining oil I reverse flushed it several times with a gallon of diesel, it worked perfectly. I'm not sure about that method here considering the diesel would have to go back thru the timing chain galley hole, but probably worth a try rather than tearing apart the entire front end. After doing this it best to get the oil pressure pumped up before restarting.
The PO of this car spent a lot of money on race motor goodies, but ignored some of the basics like a poor block surfacing job and then using a metal head gasket.. Head gaskets lasted about 15 minutes of run time, a composite one worked perfectly.