| Rerouting the PCV layout stops the car from smoking when doing tight right hand turns on the road course and/or autocross track. The stock PCV system picks up from the lowest point on the driver’s side exhaust valve cover. During tight turns oil can slosh and build up in this valve cover. It will them be sucked up into the intake plenum through the PCV system. The oil will burn off in the combustion chamber and cause the car to smoke. The reroute moves the PCV pickups from the exhaust valve cover to the highest points on the 2 intake valve covers where there is minimal chance of oil entering the system. The main write up will be the basic and easiest to do. It can be done with the engine in the car still. At the end I will provide other options you can choose to do. Let's begin. Items needed:
• 2 3/8" barb x barb connectors
• 2 3/8" x 1/4" thread to barb fittings
• 1/4 x 18 NTP tap
• 7/16 drill bit to use with the tap above
• 2 passenger side rear PCV hoses (or 1 if you can reuse your old one)
• 1' of 5/8" rubber hose
• 5' of 3/8" rubber hose
• RTV. I recommend the Ultra Copper. And of course whatever tools you'll need to remove parts from the engine as explained. You can get the barb fittings from any Home Depot. They may have the tap as well, but I got mine and the drill bit at ACE Hardware. The rubber hose and RTV can be bought at any automotive store (Napa, Checker, Autozone, etc). And the PCV hose can be bought at your vendor of choice :) . You may also need a new plenum gasket as they tend to tear when removing the plenum.
 
First you'll need to remove the plenum and everything associated with it (intake hoses, fuel lines, wiring harness, etc). Then you'll need to unbolt and remove both intake valve covers. Before removing the covers, mark each location where you will be drilling the holes for the new PCV ports. I've seen people get confused once they have them off and end up drilling the holes on the wrong sides. You want to drill the holes on the sides facing the middle of the engine. Also make sure you put the holes as high as possible. You want to make sure you leave enough room for the injector connectors to clear. As you can see, there is plenty of room as long as you put them up near the top. With the early style injectors there is even more room as they are angled more.
 Place the barb fitting on the valve cover and eyeball where you need to drill and mark the area.
 Once the holes are drilled, use the tap and thread the holes.
 
Rinse/wash out the valve covers with a good amount of water and also brake or carb cleaner. You want to make sure you get any metal particles out of the valve cover. Then install the barb fitting into the valve cover. I recommend putting some RTV on the threads to help seal it. Then you can reinstall the valve covers using factory specs.
 Since the reroute changes the location of the PCV pickups, we'll need to cap off the old ports on the driver's side exhaust valve cover. The stock layout looks like this when installed.
 You'll need to remove the old PCV hoses first if they are still attached. One way to cap these off is to turn each fitting 180 degrees and connect both with a short piece (roughly 4") of 5/8" hose. This will plug the valve cover. It doesn't matter if the hose is kinked, all the hose is doing is plugging the ports. If you can find some caps to use instead that will work as well. Also if you can find a hose with a 90 bend, it will fit that much better. If using the hose, I recommend taking the ports out of the valve cover, connecting the
hose to the ports, then putting the ports back in. Also put some RTV all the way
around the port before reinstalling it to help seal it better.
 
Now you can reinstall the plenum, wiring harness etc. Next we need to connect the PCV valves to the new ports on the valve covers. You'll need to connect each PCV hose with the 3/8" barb x barb fitting to a length of the 3/8" hose.
 
Then connect the one end of the hose to the PCV valve and simply run the other end back around the engine and up to the valve cover fitting. How you route it behind the engine is up to you. Just make sure it doesn't get kinked.
You are basically done. You will need to trim your throttle body cover (if using one) slightly to make clearance for the hoses. With the pickup ports now at the highest point on the valve covers, the oil can no longer get up into the ports
and then sucked up into the plenum. The write up above was one of the most basic ways to do the reroute with the engine in the car. It works perfectly fine with no issues. You can however do some of steps differently and I'll explain those here. It is up to you if you want to use any of different steps. Some of them require the engine to be out of the car. Most of you have seen pics of my personal reroute set up. For the valve cover ports I used a different approach. On my Z, I used AN fittings since it is a part time show car. Plus I had the parts lying around at the time. On my first engine I drilled and tapped the valve covers and used a male to male NTP to AN fitting adaptor instead of the barb fitting. Then I screwed my hose with an AN fitting onto the valve cover. With my second engine I actually welded on some AN male ports to the valve cover to give it a cleaner look.
 
Instead of running the 3/8" rubber hose, I sometimes use 3/8" aluminum fuel line. It gives it a cleaner look. You can keep things tighter/closer to the engine. And the aluminum line wont wear out or be affected by the heat the engine generates. Seems all the rubber parts in the engine bay get hard and brittle over time, this was just some more piece of mind. Don't worry though, the rubber hose used above should last for years and longer.
 
For plugging the exhaust valve cover, I used some simple screw in plugs I got from the local hardware store. I don't remember the size offhand. I tapped the holes in the valve cover, then used some RTV and the plug to seal then up. Some members have mentioned using 5/8" press-in freeze plugs with some RTV as well.
 
This last option is personal preference. It's an extra step to aid in catching and preventing even more of the oil vapors that can go through the system. Personally I don't think it's needed, but there is no harm in doing it if you choose. I have ran with and with out this mod and have noticed no difference. I do not do this mod to my customer’s cars. First you'll need to remove the baffles on the intake valve covers. Carefully drill out the spots holding it in place and remove the baffle.
 Then go the store and get a good stainless steel scouring pad. You want a well built one that is pretty sturdy. You are going to put this into the valve cover so you don't want it coming apart later. You'll need 2 depending on the size.
The thought here is it will catch the oil vapor and then it will simply drip back down into the engine and not continue on. Note: The scouring pad in the pic is not the kind to be used; it's too loose and brittle. It's only there for
reference.
 
In order to reinstall the baffle, you will need to drill and tap the original mounting spots so that you can screw the baffle back into place. Be careful though. You don't want to drill to far or you will come out the other side of the valve cover. Some of the locations are not thick enough at all for a hole so please look before drilling. Most people use 8-32 machine screws. And be sure to use some Loctite on the screws. The last thing you want is them coming undone and falling into your engine.
 Hopefully I've provided enough info here so that you can do the reroute on your own car. There are no negatives at all with using this mod. It has been street and track tested by many Z owners successfully for years. Good luck and happy Z'ing.
 JackB nimble JackB quick JackB can suck my dick =P - james-lee 11/02/01
Arrogance is the #1 weapon against Supra Owners - MikeH 08/06/02
Dallas with a Z: I like the bulge dude 05/02/03
Bezbefootball: Does dick have anything for me? 10/21/03 |
The ultimate PCV reroute write-up. - 
