N55 Head Port plugs, PCV, Catch can..?

[azshantris]

Been a while all, just a lurker and a driver lately.

Anyways, my valve cover recently got a pretty decent leak so I'm in process of replacing it. While I'm in there im gonna blast my valaves and was trying to read up on if anyone has done head port plugging and PCV/Catch can on the N55. I'm not finding much info outside of N54 since it was more of an issue there, but running over 20psi under the valave cover seems less than ideal especially with my arguably rather large turbo. My tuner suggested I could plug them and do VTA but I
1. Don't wanna be a *total* dirtbag to the environment, and
2. Think having some vacuum on the crankcase is supposed to help motor health.

Can anyone chime in and point me in the right direction or show me their setup?

edit:spelling

 

[azshantris]

Update: I'm just gonna wing and it post my results.

First issue is that the ports are apparently larger on the N55 than on the N54 so 10-32 is too small to fill the gap lol whoops

 

[wheela]

The valve cover has flapper valves for the intake ports so when you're under boost you don't pressuruze under the valve cover - any pressure there would be from piston blow by. Even then, under boost the pcv connection from the intake will be sucking vacuum under the valve cover.

I've seen some run a catch can on n55, but mixed results on how necessary they are. Seems like mostly condensation collects. The n55 valve cover does a much better job at catching oil mist than the n54. I had my intake valves walnut blasted at around 55k miles, but they weren't bad at all. Probably could have gone to 100k miles before blasting them.

If I did a catch can, I don't think I'd plug my intake ports. The n55 pcv system seems to work pretty good, other than having to replace the whole valve cover if the pcv valve fails.

 

[azshantris]

@wheela

That's a really fair assessment and aligns with everything I've read. Thankfully if I have poor results this will be mostly reversible. ( just remove the plugs). I'm gonna go through with it anyways because if it does pan out, it eliminates any potential issues with the pcv or valve cover sections potentially leaking boost under the valve cover and blowing my gasket out.
I'm going to be doing my walnut blasting at 127k now, I last looked at then about 120k and they looked great, but apparently going bigger turbo haa had a negative effect on the oil blowby any they got exponentially dirtier quickly.

 

[mwpa71]

@wheela

That's a really fair assessment and aligns with everything I've read. Thankfully if I have poor results this will be mostly reversible. ( just remove the plugs). I'm gonna go through with it anyways because if it does pan out, it eliminates any potential issues with the pcv or valve cover sections potentially leaking boost under the valve cover and blowing my gasket out.
I'm going to be doing my walnut blasting at 127k now, I last looked at then about 120k and they looked great, but apparently going bigger turbo haa had a negative effect on the oil blowby any they got exponentially dirtier quickly.

The flapper valve can fail and the higher the boost the more likely the problem. Mine did fail when running ps2 at 25psi, It could have just been age thing. There are however many guys which have been 28 psi plus (myself included p750) without drama. the newer the cover the better. If you are building a balls to the wall n55 then plugging the ports would be on the list. Good luck with it.