I get that if car doesn't warm up before it's shut down. With a large volume catch that takes a while to heat soak, the moisture will condense with crankcase vapor making the emulsion you see, E85 will just make it worse since its even more miscible in water

 

Maybe your not understanding. When I said cut the line I meant let it keep releasing gas at a good amount of rate. Not shutting it off. No way creating a draft on the second floor will completely ventilate the basement. "Natural gas" might be lighter compared to air but it will still fill the room with quite a good amount that will make a considerable amount of difference.

Similarly there are passages on the head that allow oil to drop back down to the crank case and at the same time blow by to pass up. The blow by leaking passed the rings is too high of a rate for the ventilation up top to affect the crank case to the point of completely replacing that area with fresh air. But in this case there are other gasses in the mix other than just methane.

I agree with you that the Siku Michi catch can is an excellent catch can for separating oil. However I still prefer to vent to atmosphere. And so far I havent found any solid proof of running the vacuum lines in OEM fashion other than emissions purposes. I've read both sides of the story where it helps the rings "seal" or saves from oil contamination etc... but no real proof. I'm curious as to how F1 cars are setup . (but they wont care about oil contamination just the power factor)

 

If all you want is increased performance you might want to look into a crankcase evacuation system, they use either vacuum created by the exhaust system or an electric pump that lowers pressure in the crankcase.

 

well to add my 0.02 im running a cusco oil catch can runnin from drivers side of valve cover to catch can then back to intake pipe, and ive ran it on stock engine for 10k miles, and now on built engine 10-15k, and even though my engine has been eatin up a little bit of oil, my oil level mark on the catch can hasnt even registered yet and were talkin a few years....your best bet if its that color keep an eye on your oil level and coolant level, and make sure your not startin to suck up one or mixin with another....
good luck

 

It's better to catch it than let it pass.

Without a catch the vapor and all the tubing surfaces will carry the oil to it's end point - combustion. Having a catch and Not catching any to me either means the setup is blocked or the oil isn't caught.

 

Heh quite glad search worked and I found this thread. I pulled my cans while replacing my UICP and found one with about 3-4 oz of this stuff. Got me pretty freaked out. Amusing part is last year I cleaned them out and just found regular oil, but that was in the summer. Now that I have had it sitting there I can see it start to separate. Checked my dip stick and the oil looks normal there.

<3 working catch cans for sure.