Engine Basic catch can routing?

project_88LX

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Nov 1, 2000
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I've googled and read and it seems most people refer to boosted setups or vented catch cans. I'm looking to install a basic inlet/outlet catch can for grins and because I'm bored. It's a pretty much stock setup with an explorer upper/lower intake. Do I take the big line from the upper intake into the can inlet then out of can to the PCV valve at the rear of the intake?
 
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That's exactly how you get it done. It will go from where the pcv hose goes to the intake and from the can ro the pcv valve.
 
Do I take the big line from the upper intake into the can inlet then out of can to the PCV valve at the rear of the intake?
That sounds backwards.

The current/stock flow without a catch can is from the PCV valve at rear of lower intake through the hose to the fitting on the upper intake. The catch can needs to catch these vapours. It should have the hose from the PCV going into the inlet of your catch can (as defined by the catch can manufacture) and the outlet of the can to the lower intake (this is your vacuum source to move the vapour to the can).
 
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Sounds more like an oil separator than a catch can. I’ve always thought of a catch can as vented to the atmosphere, which is how mine is. 2 lines off valve covers going to a vented can
 
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If your not running boost and don't have a ton of blowby then you really don't need one. Just put a oil separator inline and call it a day.

But if you really wanted to do a closed system style catch can I believe you would want a three port type. Something like this


And run one line from the pcv in the rear of the lower intake, second line from vacuum source on the upper intake manifold and third would need to go to I believe the clean air port on the oil fill tube on pas side valve cover.

I personally never did that setup, I've got the other one with a blocked off pcv, line from each valve cover to a catch can with a filter.
 
That sounds backwards.

The current/stock flow without a catch can is from the PCV valve at rear of lower intake through the hose to the fitting on the upper intake. The catch can needs to catch these vapours. It should have the hose from the PCV going into the inlet of your catch can (as defined by the catch can manufacture) and the outlet of the can to the lower intake (this is your vacuum source to move the vapour to the can).

Thanks! I did not realize I had it backwards.
 
That sounds backwards.

The current/stock flow without a catch can is from the PCV valve at rear of lower intake through the hose to the fitting on the upper intake. The catch can needs to catch these vapours. It should have the hose from the PCV going into the inlet of your catch can (as defined by the catch can manufacture) and the outlet of the can to the lower intake (this is your vacuum source to move the vapour to the can).

@

KRUISR

Wait, you mentioned out of PCV going into can then out of can to lower intake. I'm thinking it was supposed to be from PCV in lower intake to the IN nipple on can, then out of can and into upper intake?
 
That's what I said. The PCV grommet normally emits engine oil vapour that is normally sucked into upper intake fitting (right by cylinder 8 runner in intake). If you are looking to capture the oil vapour and not have it go into the intake, then the inlet of the can connects to the line from the PCV. Your can needs a vacuum source to draw the vapour into it, that's why the simplest is to connect outlet fitting on can to the upper intake.