Gen III PCV system

[Zubik]

This is more of an informative post. This stems from me changing valve covers. I was changing my accessory belt and saw descent amount of oil in the intake/throttle area and this led me to this rabbit hole.

Original PCV system routing:
-passenger side vent, top firewall side. This vent has a reducer ~7/64"/2.78mm in size. There's a plastic/rubber line that runs under the plenum to a port behind the throttle body, on the under side. This is the PCV system for the car. There are baffles and this foam stuff between the valve cover and the port, so oil would not get slung up it. The car always draws some fumes/oil vapor that gets burned up by the engine. There is no check valve. Here's a shot of the original restrictor in the valve cover port.
IMG_7714.jpg
-driver side vent, top firewall side. This is a completely open port w/out restriction. There's plastic/rubber line that runs under plenum to before the throttle body and plugs in on the driver's side of the intake box neck. This is just a breather to feed air when need be.

My PCV system routing:
- placed a Dough Shelby catch can on the passenger/restricted side. Everything else is routed same.

So the issue came about me changing valve covers. These are same gen, but did not have any restrictor in any of the ports. I did not realize this. The car puffed some oil on start up, sometimes, and I was searching for a reason and finally found it by taking my intake box off. Right away I thought of the PCV system and led to this post.

My solution to this was to make a restrictor myself. The catch can lines are 5/8" and the port takes a 1/2" line. I had a hose reducer right at the passenger side valve cover port. What I ended up doing is designing a new reducer w/restrictor built in and 3D printing it.

Here's some pics of the design and the print:
IMG_7708.jpg
IMG_7712.jpg
IMG_7713.jpg

1st impressions was that the car idles better. The oil issue at the throttle body has been resolved.

This is clear FormLabs resin. On the old valve covers I printed another reducer w/a 90 degree bend in it. I ran it for ~two years and it held up fine. Don't judge the old one. As one can see my design skills improved a bit =P
IMG_7715.jpg

[GTS Dean]

A useful post and a very slick DIY solution! I think that for 1 or 2 years, the Gen 3 engines had a PCV valve, then went to Orifice Control ventilation.

[ViperSRT]

Interesting. My Gen 3 (2003) uses a PCV valve and not a fixed orifice. Sounds like the valve cover you received was intended for systems with the valve. Guess we have another mid generation change that many of us were unaware of. Great find and solution.

[Zubik]

My car is a ‘04. So maybe the early cars had an actual check valve?

[Old School]

The 2003 and maybe the 2004 had PVC and vent at the rear of the valve covers. Later years were toward the front.

[Zubik]

So I got newer covers, I guess. My port was by firewall and new is towards the front of engine.

[proedge]

My 2005 only had ports on the front of each valve cover. I removed those fittings and got the holes drilled for NPT style adapters and installed a catch can. Plugged off the bottom of the intake, no more oil in my intake hopefully

[proedge]

another pic