PCV System in Pictures

[mrk1]

I have a motor apart in my garage and thought I would take some photos to show just where the different ports go.

There seems to be some debate about if both lines need to go to a catch can, or do NA only 1 and boost needs 2.



The Red arrow points to the PCV valve in the block back behind the intake manifold.

Green points to the hose that comes out of the block under the AC Compressor



With a motor apart we can see this is a vent for the front timing chain area. Many people report not getting much out of this line but there is a direct opening between the top of the crankcase and the front timing chain area.





The PCV valve outlet is feed from this chamber on the back side of the block. This chamber is feed from channels in the block that lead all the way out to the valve covers in each head (top circle). There is also a channel leading down to the oil pan (lower circle) This is probably the oil return passage for whatever builds up in here. This passages ultimately runs down below the oil level.

Whats inside the FA20 PCV valve,



Very basic, metal plunger with a small spring.

What about a PCV valve from a boosted car? No real difference, maybe a heavier spring. Factory boosted cars have a different line layout so the valve alone isn't the only difference.




I don't intend to tell anyone how to route there lines, just to show what you can't see from the outside.

[mrk1]

Personally I run both lines into a Vent to Atmosphere can with the PCV drilled out on my turbo car. The way I see it, if you leave the factory line off the back of the intake to the PCV thats a dead end. Under load the intake is pressurized, this is also when you see the most crank case pressure. Thats pressure on both sides of the valve, sure the manifold side is hopefully more and will keep the valve shut but what happens to the crank case pressure then? On a NA car like the system was designed for the intake is in vacuum under load. This allows the crank case pressure to be relieved by the valve.