Do I need a check valve on my intake line?

[CLZinn2]

I'm planning on installing a KazeSpec Engineering 2 Chamber Oil Catch Can on my naturally asperated (Bored to 2.0) NA. Do I need a check valve on the intake line? I'm also doing my own catch cans on my 1996 Dodge Ram, as I just replaced the engine with a properly rebuilt one, so now I should have No Sludge issues, like in the past and I'm not sure if I need one there as well. So are check valves necessary on intake catch can lines or not is the Question. Thanks,

[atlex]

Need a bit more info but here's the general picture from my experience..

On an NA car (built or not) with a regular plenum, stick with the regular PCV, the check valve functionality of the PCV will be fine, you really shouldn't need an additional check valve in the circuit, whether or not you have a catch can in it before the fumes get to the intake plenum. You will hurt the setup by removing the PCV but you will not hurt it by adding a check valve in addition..

Without the PCV you get unrestricted vacuum so strong it will suck quite a lot of oil and fumes out your head. like 100ML in 100 Miles (ask me how I know! ).

On an NA ITB car I think VTA makes most sense (even VTA via a catch can), to avoid fowling up whatever vacuum lines remain with breather fumes. Vacuum lines aren't _meant_ for breather fumes. Catch cans aren't perfect.

On my turbo car with a standard intake, the flow goes.. PCV - catch can - Check Valve - Intake Plenum. - the check valve is there so that the PCV doesn't get to experience boost from the intake it wasn't designed to see, the PCV is there to act as a restrictor because unrestricted vacuum sucks too much.

[— kung fu jesus —]

The only check valve I see in this setup is the PVC in the stock location.

oil-catch-can.jpg

[atlex]

EDIT

That'll work fine if it's really two chambers (fully sealed off from each other inside) in the catch can.

Flow will be from the filter, into the nearest cam cover port, through the cam cover (picking up the blowby), through the PCV valve which you absolutely should retain, and via the second chamber (where most of the blowby and residual oil will end up), and then, into your intake. Nice design tbh !

[CLZinn2]

Thanks, Steven. Yes I saw this, but when I was reading someone's install, I got confused.. I'm doing 2 cans on my Dodge ram install, so I'll use the same principal.