Planning on building a secondary crankcase vent system similar to some European cars to create some vacuum in the crankcase to improve ring sealing and reduce oil consumption. Going to use the balance shaft check bolt for vent and oil drain back, tie it in with PCV valve. Any ideas?

Using this I presume...

http://www.streettunedmotorsports.com/parts/stm_balance_shaft_inspection_hole_breather_fitting.htm


I was thinking of doing the same, but not as a drain; just a vent to a catch can plumbed back into the intake.

^I use that hole, and it pushes a lot of oil.

Vents should be up top. This has already been done and without the can thats how it is from the factory.

Here are some good reads:

• http://www.dsmtuners.com/threads/4g63-block-vent.472409/
  
• http://www.dsmtuners.com/threads/rear-bs-delete-only-and-pcv-idea.480368/

Thanks. I'll see what I can do with those information.

I'm going to vent from the stock location on the VC along with the BS inspection hole. Just installed the STM 6AN vent on my block a little while ago while assembling the engine.
See, the idea here is that CC gases trying to escape MUST go up with the traditional vents off the VC. When venting from the block then, in theory, oil isn't fighting CC gases on it's way back down from the head to the oil pan. Upside? More oil getting back to the oil pan with less resistance.
Downside? If you have some blowby probelms then CC gas pressure may be high enough to spew a ton of oil from the balance inspection hole. I figured i'd split the difference and vent from top and bottom.

I'll eventually update my build thread and post results when emptying the catch can.

Fwiw, i didn't use a catch can before and had barely ANY oil in my IC pipes or my compressor housing on my turbo. Blow by was not a big issue for me. This is more a plan for the future type thing. Eventually when you wring 300hp/liter out of an engine you will be getting crankcase pressure. I drove 4500 miles wit hno problems. 5558 pte.

I think you're over thinking this and I also think that the balance shaft hole isnt a suitable vent, its too low.if you want lots of vents or bigger vents they should go up top away from the crank and preferable behind the baffle or be baffled on their own like some vented oil caps.

I very well could be. Well, if nothing else it will be aesthetically pleasing ha. Serve its purpose as well.
I had a very long post with a lot of people weighing in on this last year when i was active on the forums. We discussed it in depth. I'll try it out and yes, i agree, only the worst blow by will cause an impedance in oil drain from the head back to the pan. That would indicate you need a rebuild. I ran at 33psi, calibrated at 52lbs/min flow and had nearly zero blow by from what my IC piping and compressor housing look like.