Boost = PVC Air/Oil Separator

[Blown]

I think it is a good idea. It should reduce emission of burnt oil and keep away the possibility of fouling plugs. What do you all think for boosted applications and/or do you run one?

I have been running my Kenne Bell boosted rig without the PVC valve, just a hose from crankcase to vacuum, as too much pressure was building in the crankcase. It would push-up the oil dip stick and actually pushed some oil up when at 9+lbs of boost. It is getting some oil in the intake pipe at the PVC hose. I ordered a Moroso oil/air separator from Summit Racing to install and capture that oil. It was a little spendy unit but came with everything, hose, mount, hardware, fittings, including a tap at the bottom with valve to drain the oil. I will post-up some pictures later when I install it.

 

[CDW6212R]

The crankcase pressure is separate from the PCV catch can idea. You will still need some extra vacuum to maintain a decent low pressure in the crankcase. I learned that PCV trick with an old 85 Crown Vic, which was worn out and blowing oil up into the air cleaner. I ran full vacuum to one valve cover, and found a higher flowing PCV(they vary by car), to limit the amount of air pulled through the crankcase(which bypasses the carb or MAF).

A catch can is great for the excess oil from the VC's or PCV, but the type of oil separator inside the valve cover is the biggest key item. Some VC's allow to much oil to get out through the hose, many aftermarket units of course. So I'd work on the VC which the crankcase hose is pulling from the most. Do that and it will reduce the amount of oil which gets caught by the catch can.

 

[Blown]

I have run a larger pcv valve in a former boosted rig. There is, obviously, more blow-by in a boosted engine and a need for more volume of air removed from the crankcase. I am currently running additional vacuum with the same size hose as stock with no pcv valve. (side note: I tuned for the extra air flow around the IAC with my Tweecer.) The catch can is essentially the filter/baffles in the valve cover like what you are talking about. I am running a ford F150Bronco lower intake so no pcv there and Explorer valve covers so no pcv there, so where do you think I pulled vacuum for the crankcase?

Anyway, I too believe in more vacuum volume to remove additional blow by in a boosted application and some type of air oil separator.

 

[CDW6212R]

I look forward to how you work that out, it may help me to decide the best way for my boost project. I hope I can make a bigger baffle under the VC's I want to run, and the need for a catch can may be less. I think how much oil people collect in the PCV system is related a lot to the VC baffling. Many VC's have almost useless baffles, so with boost those push out a lot of oil.

I got the idea of altering the VC from a Corral thread where the subject was a pair of billet valve covers. Along with the high cost, I forgot, long time ago, maybe $700+, the underside had a long shallow baffle(long metal plate bolted onto the underside). I have no idea how much space I will have for rockers with my chosen FMS VC's. If they have room, and I'm already expecting to have to weld the holes(old Ford type), I might try to attach a long baffle plate such as I saw in that thread I mentioned.

The Explorer 302 has a small space where the bottom right idler pulley is. I'd like to see if a small vacuum pump can fit there, that would be good for the crankcase pressure.

 

[Blown]

I am pulling vacuum from the crankcase at the oil filler on the valve cover. I thought it was high enough it wouldn't suck much oil. It's sucking oil, ha!

This also made me want to be able to filter and not recycle/burn the dirty aerosols out of the crankcase.

The challenge will be mounting it and in a location I can drain it............................then monitoring it and draining it, another maintenance item?