PCV Reroute

The PCV system is designed to allow oil vapor from the crank case to ventilate into the intake manifold where it is combusted. However, anyone who has taken their Z around an autocross/road course has probably been black-flagged for excessive smoke. The stock PCV system allows LOT of oil to get sucked into the intake, which ends up spewing smoke out the exhaust.

The PCV Reroute will allow you to retain the function of the PCV system while helping to reduce the amount of oil consumption caused by high lateral G-forces in cornering.

Prerequisite: Intake Manifold Removal.
Images from Woody75's TT.net writeup here.

Tools Needed

• Pliers
• Cutting tools
• Philips and flat-head screwdrivers.

Parts Needed

• Power Drill
• 7/16" Drill Bit
• Liquid Gasket maker
• 1/4 x 18 NPT tap
• 3/8" NPT tap
• 2x 3/8" to 1/4" Barbed-to-Threaded fittings
• 2x 3/8" threaded NPT plugs.
• 2x 3/8" to 3/8" Barbed-to-Barbed fittings
• ~4 ft of 3/8" rubber hose

Procedure

Tapping New Breather Ports

1. Remove the Valve Covers.
2. Using a 7/16" drill bit, drill new breather holes in the intake valve covers. These should be on the "center" high point on the intake valve cover, point towards each other (towards the center of the engine).
   
3. Tap these holes (lol) with a 1/4 x 18 NPT tap.
   
4. Thoroughly clean the valve covers using brake parts cleaner to get rid of any metal shavings. You want these totally clean.
5. Install your 3/8" x 1/4" Barbed to Threaded Fittings. Use a small amount of liquid gasket to ensure a good seal.
   

Removing & Capping Old Breather Ports

1. Locate the original breather ports and remove them with pliers (they're just pressed in).
   
2. Tap the holes with the 3/8" tap, matching whatever thread pitch your plugs are.
3. Thoroughly clean the valve covers with brake parts cleaner to get rid of any metal shavings.
4. Install your 3/8" NPT plugs. Use some liquid gasket to make a good seal.
   

Alternatively, some use 3/8" press-fit freeze plugs and liquid gasket to avoid having to drill and tap.

Routing The New Hose

1. Run some 3/8" hose from the new barb fittings to the approximate location of the old breather ports, near the PCV valves. Don't connect it at the valve covers yet, just size to cut.
2. Use a 3/8" x 3/8" barb fitting to joint the two hoses together. Install clamps to ensure a tight fit.
   
   

   This person also opted to loop the old breather ports to each other.
   
3. Reinstall the intake manifold.
4. Connect the new hose at the valve covers.
   

Some people opt to instead use metal fuel lines instead for a cleaner look. This allows you to run the hose closer to the engine without fear of degradation from heat damage.


Going a step further, some opt to remove the PCV system completely.