[JonEQuest]

OK, I am new to this engine but unfortunately I am having to learn everything fast. I am in the process of changing a bent rod and going back together with everything rebuilt and "improved" so I want to do an external PCV system.

P.S. I am going back with MMP silicone stock location inlets, MMP silicone outlets, MMP charge pipe with Tial style bypass valve (I don't want the WHOOOSH sound), and an e-bay OCC. I also ported and polished the head ports, lapped the valves, etc.

While I had my head off I went ahead and tapped/plugged the 6 holes going to the intake ports. I got a generic oil catch can and plan to use it now that my valves are clean. My question is, that if you are removing the (PCV valve The cone one with no fitting attached) and putting in a straight flow fitting that goes to the IN side of the catch can, what are you doing with the other side that had the vacuum to it before? I also don't "see" how there are two PCV systems, high side and low side. There is one PCV valve and a vacuum port next to it to pull gases/oil out now at the rear of the valve cover, right? Is there another PCV I have not seen yet? I really want to understand what is happening with the PCV and where you would attach a second catch can if you already use the PCV port at the valve cover for the 1st catch can. Is the cone one the "low" side and the one next to it that has a vacuum fitting when stock the "high" side? Any photos with arrows and description would be great. Maybe I am a little "special" but I just have not had that "A-HA" moment with this high side/low side thing yet. Funny that THIS confuses me, but I have 95% rebuilt the whole engine so far from YouTube videos and online manuals.

[JonEQuest]

Bump

Search around for the RB options available...should answer your questions.

[JonEQuest]

Originally Posted by FCobra94

Search around for the RB options available...should answer your questions.

I kind of figured out about the internal low pressure PCV system versus the high pressure external venting one. I have a catch can and I guess I'll get a second one if I need one. My main question is the two fittings they sell you. is the one that replaces the cone-shaped internal PCV just a block off? and is the one that sits more to the passenger side and has the suction vents on it that goes to the rear turbo inlet just a pass-through fitting or does it have a PCV flapper? I have tons of fittings in my garage and can quickly fabricate a pass-through fitting. I could also quickly fabricate a block off for the internal PCV if that's how it works.

P. S. I have already plugged the six ports in my head.

[arkie6]

On my '08 335i I am running "high side" crankcase ventilation only. The "low side" or high vacuum side has been completely blocked off.

When I did my valve cover gasket replacement and intake valve walnut blasting, I tapped and plugged those ports in the head for the PCV valve "low side" high vacuum suction source. This isolates suction to the installed PCV valve in the valve cover and effectively renders it non-functional.

I then removed the "high side" PCV flapper valve and accordion hose. I installed a short piece of 1" rubber hose where the flapper valve was installed and then inserted a long piece of 3/4" rubber hose into the 1" hose and held in place with ultra black RTV and black nylon zip ties. I routed this 3/4" hose to my oil catch can and then routed the other side of the catch can to the rear turbo inlet pipe where the flapper valve previously attached using the same 3/4" hose in a 1" hose to make the connection.

I flipped the orientation of the turbo inlet hose and PCV heater assembly where the PCV flapper valve accordion hose previously attached 180 degrees by filing notches in the attachment point to avoid needing a 180 degree U bend hose and make the hose routing more direct to the catch can. See discussion in this thread: https://www.e90post.com/forums/showthread.php?t=1513852

My ebay catch can (similar to BMS) has a drain line with 1/4" dia hose and shut-off valve so that I can drain any accumulation without having to access or remove the catch can.

I have had this installed for several months. It seems to be working fine. I honestly don't catch much oil in the can, but my engine at 113,000 miles is still 100% stock and uses little to no oil (~1/2 quart between 7500 mile oil changes with Castrol Synthetic Euro 0W-40). I catch more water condensation than oil. I recently checked the inside of my charge pipe and it is bone dry. Previously when I pulled it off for the valve cleaning it had a light coating of oil, but this wasn't unexpected given the 100,000+ miles on the car at the time.

[JonEQuest]

Originally Posted by arkie6

On my '08 335i I am running "high side" crankcase ventilation only. The "low side" or high vacuum side has been completely blocked off.

When I did my valve cover gasket replacement and intake valve walnut blasting, I tapped and plugged those ports in the head for the PCV valve "low side" high vacuum suction source. This isolates suction to the installed PCV valve in the valve cover and effectively renders it non-functional.

I then removed the "high side" PCV flapper valve and accordion hose. I installed a short piece of 1" rubber hose where the flapper valve was installed and then inserted a long piece of 3/4" rubber hose into the 1" hose and held in place with ultra black RTV and black nylon zip ties. I routed this 3/4" hose to my oil catch can and then routed the other side of the catch can to the rear turbo inlet pipe where the flapper valve previously attached using the same 3/4" hose in a 1" hose to make the connection.

I flipped the orientation of the turbo inlet hose and PCV heater assembly where the PCV flapper valve accordion hose previously attached 180 degrees by filing notches in the attachment point to avoid needing a 180 degree U bend hose and make the hose routing more direct to the catch can. See discussion in this thread: https://www.e90post.com/forums/showthread.php?t=1513852

My ebay catch can (similar to BMS) has a drain line with 1/4" dia hose and shut-off valve so that I can drain any accumulation without having to access or remove the catch can.

I have had this installed for several months. It seems to be working fine. I honestly don't catch much oil in the can, but my engine at 113,000 miles is still 100% stock and uses little to no oil (~1/2 quart between 7500 mile oil changes with Castrol Synthetic Euro 0W-40). I catch more water condensation than oil. I recently checked the inside of my charge pipe and it is bone dry. Previously when I pulled it off for the valve cleaning it had a light coating of oil, but this wasn't unexpected given the 100,000+ miles on the car at the time.

Thank you so much! This is the type of information I was looking for. I will check out your post later to see how you did everything when I get home from work.