As any N54 owner knows, carbon buildup is always a concern. Cleaning the valves on my 535i with around 120,000 miles on the odometer was an eye opening experience. Spending the better part of a day cleaning hard to reach places with an assortment of brushes and brake cleaner was not something I wanted to have to do anymore than absolutely necessary. I had always wanted to try the oil catch can setup from Burger Motorsports to try and stop some of this buildup, but after considerable research, it seemed as though my rather reserved and light-footed driving style wouldn’t result in catching much of anything. Valve cleanings were just something I was going to have to get used to doing more often than I would like. Seeing as how my newly acquired 135i just turned 60,000 on the odometer, this maintenance chore was already on the docket to be done very soon.
In the meantime, I had began to further investigate a more long-term solution which is when I discovered the RB External PCV/Dual Catch Can kit. These fittings and hoses would externalize the PCV system and catch any blow-by with an oil catch can. The benefits to this setup are plentiful and should help keep the valves much cleaner, keep the engine/turbos from smoking, and allow for easy dumping of the catch can contents if you purchased one.
At this point I went ahead and purchased the recommended Mishimoto 2-Port OCC as well as the full N54 OCC kit from Burger Motorsports. This would mean I would have both the low and high sides covered for oil blow-by. This should be the most effective solution at the moment to avoiding PCV related issues and the best at keeping those valves from gunking up prematurely. Total cost ended up being right at $500 for everything.
Some close-ups of the BMS OCC:
The external replacement for the current internal RB PCV valve I'm running now:
This Mishimoto seems to be really well built:
Instructions were to scrap the fittings supplied by Mishimoto and replace them with the RB heavy-duty versions:
The next task at hand is finding a clean, proper place to mount the catch cans.