I went to the junk yard a few months ago and decided just for grins to take apart a valve cover off an old FS-DE in a GE 626 to look at what it is like inside
I was surprised to find the lack of baffling on the PCV valve side and a poor baffling design on the breather side... all it was were a couple of compartments with a tiny 4mm hole for air to pass in between each one of them... while it would work to some extent as an oil separator, it is obviously a piss poor design! there's not much of any way for oil to condense and drain itself back out into the engine
now imagine if this was all on a boosted engine... under boost, the blowby will just shoot itself out through the breather side and out into the intake... the suction from the turbo helps exacerbate this too
here are some crappy cell phone pics I took of the valve cover... the green shaded box is a halfassed impression of the air scoop at the bottom of the valve cover plate that feeds vapors/air to the PCV valve... the red arrows obviously are the PCV vapor path.. the blue arrows are fresh air from the breather hose hooked up to the intake (normally)
the diagram depicted is normally under OFF BOOST conditions... the path reverses when under boost... and if a good PCV valve was installed, there should be no airflow going through the PCV side (which thereby boosting the crankcase)... but blowby occurs anyway, and will force vapors out through the breather side
I believe what needs to be done to truely fix this oil burning problem once and for all is to come up with a way to KEEP the oil in but allow air to come out... you don't want to plug this shit up because it will blow up the seals and cause a leaky mess!
the PCV side is relatively easy... a simple stainless steel pot scrubber pad should work as a temporary means to condense oil and let it drain the collected back out (like under boost or when engine is off)... the breather side isn't... the space is small and due to the separate compartments, there's no easy way for oil to just drain back out into the engine... stuffing scrub pads in there isn't a long term solution... what might end up happening is the chambers get flooded and oil will piss out after some time without any means of going back into the engine
the most likely possible solution (which I don't have the means of personally achieving at this time) is to machine new covers or modify existing ones and weld on baffle plates to it to catch oil and somehow allow it to drain out
doing this ought to eliminate MOST of the oil escaping out the breather hole under boost as well as oil going into the PCV valve under cruise conditions...
achieving this will allow a simple 30 minute fix to any protege without going through other expensive means like an oil catch can (not a good solution.... imagine a couple of laps around the track and all your oil is in the catch can and NOT the engine), or an oil separator tank (which means welding a bung on the oil pan to allow for separated oil to drain back to the engine)
FWIW, other engines like the Volkswagen VR6 motor have a pipe cleaner looking thing that is installed inside the valve cover's breather system to act as an oil separator... poor quality oils or lack of oil changes caused sludge build up there (as well as other parts of the engine of course) first and made the engine run like shit... other engines like domestics have a oil separator/filter that is installed right on top of the valve cover inline to the breather hose... BMW uses a factory oil separator system that drains oil back through the dipstick tube... I have yet see a japanese engine that have any of these superior characteristics... fucking cheap assholes!
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Originally Posted by BRIAN MP5T
