N54 RB External PCV system review and DIY
 

I wrote this review and DIY guide and shared it on a few of the other forums I'm a member and wanted to share it here for any of the E60/61 N54 owners that may not browse all the forums.

This is a very well though out kit and I am an avid supporter, especially after a few moths of use. I think that anyone who cares about there N54 motor or there wallet should do this conversion. It will make your next walnut blasting potentially your last and will keep everything in the intake track clean.

When I purchased my car one of the first things I noticed was all the oil leaking from the intercooler to intercooler piping connections. At the time I decided to remove the stock intercooler to rinse it with gas and also added a charge pipe with Tial BOV. Within a few weeks I noticed that my BOV was shooting a fine mist of oil and the pipe connections were wet again. I was amazed at how quickly the intake track was recoated with oil.

At that point I decided it was time to get everything cleaned up again and do a walnut blasting. I cleaned the throttle body and intake manifold thoroughly during the process. My RB kit was on order and slated to ship soon so
I put the car together and drove it for a few days while I waited for it to arrive. When it showed up I installed it immediately to stop everything form getting gummed up with oil again. So the kit is installed, walnut blasting is done, the intake, FMIC and piping are all clean, now comes the true test.....

I make frequent trips between Boston and NYC so my car gets a good deal of highway, city, idling, cruising and spirited pulls. After 1.5 trips and a few miles around town (~400-500 miles total) I checked my catch can for the first time.
I was pretty surprised at what I found, the can was probably 1/4 filled with oil!
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That was test number one and the result were looking promising.
Test number two came about a month and roughly 1k miles later when it was time to install my VRFS 7" FMIC and piping. When I pulled out the stock intercooler and piping a found it to be as clean as I left it when I did my walnut blasting service. No more oil around the TIAL bov, in the charge pipe, TB or anywhere else for that matter.

It's now been over 7k miles since the kit was installed and I've dumped a few cups of oil out of the catch can. I love this system :)
It's nice to know that this kit works as advertised and I never have to worry about my FMIC getting filled with oil or worry about walnut blasting for a very long time. This is a very well thought out system. The quality, fit and finish are top notch. It offers a performance gain, less oil consumption, less smoking, a reliable OEM toyota PCV valve, eliminates oil contaminating the valves and intake track, eliminates oil effecting the A/F ratio in the combustion chamber and helps with cleaner emissions. That is a no brainier and a giant win if you ask me!

I plan on performing one more long term test which will be a periodic inspection of the intake valves. I will be removing the throttle body every 10k miles to taking a look with my borescope. That should eventually give me an idea of what the new walnut blasting S.I. should be.

This installation of the RB External PCV system with Mishimoto catch can was performed on an E61 and outlines the full procedure for the E60/E61 chassis. For all other models it is a matter of gaining accesses to the back of the valve cover to start the conversion. The instructions beyond the cowl removal portion of the job apply to all N54 powered cars. I will label this as Step 1 so for all others Step 2 will be your pickup point.

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I am using a BMS OCC on the high side which I retained and also decided to mount my Mishimoto catch can on the bar along side of it. The mounting location and the mounting solution I used may or may not be permanent. Where you mount the can and route the hoses to is up to you and does not affect the rest of the procedure.

Step 1:
Cowl removal-


Remove the cabin air filter housings by releasing the clips and turning the 13mm plastic nuts until the tabs release.
Remove the hood seal, battery cable cover and rubber gutters along the fender edges.
Now release all of the plastic 13mm nuts on the cowl covers as well as the 2 torx screws at the rear of the strut towers then remove the cowl cover.
Now remove the battery cables from the guide, remove the 2 plastic push pins from the strut brace and remove the plastic cable guide.

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Step 2:
You will now be able to remove the 4 hex bolts holding the engine cover in place. Remove those bolts and then the engine cover.
*If you are still using all 4 bolts it is recommended that you do not reinstall the 2 rear bolts when the cover goes back on. It will not cause any issue and it makes it much easier to remove later.

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Step 3:
Locate and remove the internal PCV valve at the rear of the valve cover.
You will see the PCV valve cap bellow the #6 fuel injector feed line. (I found it easier to work with the injector feed line removed. If you choose to remove the line with a 14mm open ended or box wrench remember to pull the fuel pump fuse before doing so. )
Once the fuel line is removed you can then take a 13mm wrench and remove the PCV cap. From there you will see the internal PCV valve sticking out. It is pressed in with an O-ring keeping it tight. You can grab the end of it and pull it out. If you have trouble try threading a tap or drill bit in to it and grabbing that with vicegrips. Be sure to carefully pull straight back to avoid cracking the plastic valve cover. You can now discard both of those pieces.

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Step 4: Install the new RB external PVC fitting.
You will first want to make sure you lubricate both O-rings with fresh engine oil. Now push the valve in to the valve cover as far as you can and begin to thread the fitting in with a 1 3/16” open ended wrench.
It helps to apply pressure to the valve as you begin threading the fitting but be very sure that you have it square considering the fragile plastic threads in the valve cover.

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Step 5: Choose the catch can location, mount your can and run the “IN” hose.
Use the supplied aluminum catch can fittings that came with the RB kit and discard the plastic fittings that Mishimoto sticks in the can.
You can now cut the hose to the proper length to run it from the PCV valve to the “IN” side of the catch can. Use the supplied clamps and install the hose.
*Make sure you have enough hose left to go from the catch can to the throttle body. If not, choose a different location or get more hose!


Reinstall the #6 fuel injector feed line.

Step 5: Remove your DCI, Air Box or whatever filter setup you may have unless it’s a turbo side setup 

Step 6: Install the T-Fitting to the throttle body.
To do this you will press the sides of the plastic clip holding the EVAP line to the back side of the throttle body and disconnect the line. You have also have to run your hand down the line towards the back of the manifold till you feel the rubber holder that keeps the line secured to the intake manifold. Pull the rubber holder off of the bracket. You need to do this to allow the line to back up so you have space between the throttle body and the line for the new T-Fitting.
Now you can push the T-Fitting in to the throttle body and lock it in with the supplied E-Clip then reconnect the Evap line to the other end of the T-Fitting.

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Step 7: Run the “OUT” hose
Attach the remaining hose to the T-Fitting along with the supplied clamp. Route it up to the catch can and make sure you do so in a way that will not interfere with the Air filters, etc.
Now cut and extra length off of the hose and attach it to the “OUT” side of the catch can with the supplied clamp.

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Step 8: Reinstall the air filters, engine cover and cowl parts.

Step 9: Enjoy not having to walnut blast your intake valves for a long time and remember to check your catch can every 500 miles until you have a good understanding of how quickly it needs to be emptied.

**Plugging the ports on the cylinder head is recommended but the kit will function without doing so.

Part 2: Cylinder head PCV vent plug install

To install the provided 10-32 head plugs you will need to remove the valve cover and intake manifold. I'm not going to cover the VC or intake removal process since both are well documented on these forums and in the Bentley manual. I am going to focus on the correct procedure to avoid introducing aluminum shavings to the motor and getting a good thread coil at the correct angle. I will however remind you to pull the fuel pump fuse and make sure the engine is cold before you start this process!
Also well doing this it is a great time to take some maintenance items off the list. A new valve cover gasket and new intake runner seals are recommended. It's also the perfect time to perform the walnut blasting service and replace your spark plugs if needed.

To do this job you will need a good 10-32 tap with a T-handle, shop towels, wheel bearing grease, brake cleaner, blue loctite, a vacuum and compressed or canned air.

Once you have the intake manifold and valve cover off you are going to start buy making sure the valves are closed on the applicable cylinder then stuff a half sheet of shop towel in each intake port. I'm suggesting that you use a half sheet because you only want to fill the individual valve ports up to the divider. The reason being is you want to stay bellow the exit of the PCV vent port in the cylinder head so that you can collect debris in a controlled manor.

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Next you will fold up a piece of paper so that it is just wide enough to fit in to the intake port, coat it liberally with wheel bearing grease then slide it in the intake port being sure that it is bellow the PCV vent hole. This is going to catch most of the metal shavings that fall through the port as you run the tap.

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Now you will want to stuff some shop towels in the cylinder head along the camshaft bearing ledge to avoid metal shavings or a 10-32 plug falling in to the motor.
*** I ONLY HAVE THE TOWLES REMOVED SO I COULD TAKE CLEAR PICTURES***

Apply a coating of grease around the top of the port on the cylinder head and also to your 10-32 tap. Grease is your best friend right now, it is going to collect a good portion of the metal shavings.

Now you are ready to tap.
The angle is the key to this so you will want to stand along the left fender and look at the cylinder head along the intake ports. You will be able to see the shape of the port running from the valve cover mating surface down towards the intake runner in the casting. This is the angle that you want to make sure you set your tap to. Once you feel comfortable with the angle slowly start to run the tap in the hole a few turns and recheck your approach angle. If everything looks good you can run it in about 1/4-3/8" turning it in a few turns at a time and backing up a turn in between passes.
Don't worry about going down a little too much, as long as you have the plug bellow the top of the head and not all the way to the runner it will serve its purpose.
Now remove the tap slowly and try not to tip it on the last turn coming out since you will only have thread on one side of the hole that you could damage.

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Now wipe the grease and metal off the top of the hole, shoot some brake cleaner and air in the hole and pull the paper out. If you did it right your paper should look like the one in the picture above. From there you will vacuum out the port and remove the shop towels.

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Next you'll apply a drop of blue loctite to the 10-32 Plug and thread it in to the newly tapped port with a 3/32 hex key. Be very careful not to drop the plug into the cylinder head or you will be sorry.

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One is done and you are ready to set yourself up for the next cylinder. Repeat the process until all 6 are installed then put the engine back together and enjoy!

Great write-up RCB. You've done a lot of great stuff to you car. Keep it going!

This PCV install for the N54 seems incomplete, or wrong.

For starters, you said this was the high side exit for the blow-by gasses. Then you route them through a new T Filling to the throttle body. But the BMW literature says the high side is supposed to go to the pipe that feeds the bank 2 turbo. (The pressure at the TB would be high and not pull gasses out when on boost.)

You also don't mention the location where the hose from the old PCV used to go, which I believe is to that inlet tube for the turbo. I assume you would cap it off, instead of leaving it as a way for unfiltered hot air to enter the intake system.

Have I missed something?

This is an old post and RCB hasn't posted anything in over a year. You might want to try PMing him for a direct answer.

Upon further review...

I HAD missed something. Several things. I think I get it now. The "high side" is mentioned but that's not what this is about. (That's the side with the flapper valve, that takes blow-by gasses to the turbo inlet when the car is in positive boost mode.) The poster said he already had a different catch can there, and that's probably why his IC and tubing are cleaner now.

This post is all about the other side. When there's negative pressure in the intake manifold, the blow-by gasses are pulled through the internal PCV valve and routed to the little holes above each of the intakes. So normally, the gasses come through the PCV, and then they go around in and back into the valve cover, down to the holes in the head above the intakes.

In this post he takes the cap to the PCV off and then routes the air to the TB. That means the little tubes from the intake are open to the atmosphere. Not good. That's why he says to tap the holes and insert plugs. I get it.

He then connects the tube from the PCV to a catch can and then to the TB. On normal cars that would be fine. In this case, that means the tubing and catch can would have to withstand the positive pressure from the turbo. Clamps and tight fittings would be needed.

So this is a double-catch can approach.

Isn't there an easier way?
 

Help me out here.

When the intake manifold has a vacuum, the normal path for the blow-by gasses is to go through the cyclone separators, through the internal PCV valve, then around the PCV valve and then down to the intake ports.

When installing an external catch can on this low side, wouldn't it be easier to block the path to the intake ports there, at the internal PCV, instead of removing both the intake and the cam cover, and drilling/tapping 6 holes?

It seems that someone could put a piece of tubing with silicone sealant around the internal PCV to block the path down to the little intake ports. It it works, it would be much easier.

Has anyone tried that?

Plugging the intake ports with the plugs is removing the stock vacuum source for the stock PCV system since it's now using a new vacuum source, AND the plugs also prevent the VC from getting positive pressure when the car is on boost. Blocking it elsewhere would not prevent pressurized air (boost) from pressurizing the valve cover. Stock PCV is replaced so that it's not internally routed anymore, and is now going to the oil separation canister, which is connected to the new vacuum source.

I'm just researching this now as I'll be installing the external PCV at the same time I walnut blast the intake on my 2008 E61. I've been researching this myself to see if there was a better DIY of doing this, but so far this kit looks like the best way to do it. My only change is that I want to use a Provent 200 as my oil separation canister.

Rabin

Yes, that's how I see it too.

The little holes above each intake port route air back to the PCV. When the intake has negative pressure (relative to ambient), blow-by gasses get sucked through the open PCV into the intake ports through those little holes and passageways. When the boost is positive air would flow the other way, which would close the one-way PCV. Then positive pressure would be in the intake and in those passageways up to the PCV.

So that part of the valve cover is designed to handle positive pressure from the stock turbo. And if one removes the cap off the PCV and routes the air flow from the PCV in another direction, like to an external oil catch can, then the open passage to the intake ports certainly should be closed. (Like any intake leak should be closed.)

I don't disagree that the solution outlined above would work, and might even be best. But that's a lot of work, to remove the valve cover, drill 6 holes, tap them, insert little plugs, and replace the valve cover..

In many cases, I usually like to give cheaper/easier solutions a chance to work first. Here, if I had one of these cars and I were routing the PCV gasses to the outside, I'd try to block the passage to the intake ports at the PCV end first. Seems like it would be fast and easy to put silcone, JB Weld, or something similar to seal the path there, before it branches into 6 passageways to the intake ports. I also like trying a solution like this when there is no downside. If it doesn't work, then one can always do the more involved process of permanently plugging each of the 6 little holes.

(I'm glad to be proven wrong if someone has already tried this and learned that it didn't work.)

Also, on my nephew's '08 535i, every time we've pulled outlet hose off the intercooler (with the car leaning that direction), just a little oil has dripped out (no more than a few tablespoons after a year of driving). His car is stock, low mileage, and it's his daily driver, so he's not on the boost a whole lot. With that usage, the need for a oil catch can on the high pressure side seems low. (The path from the valve cover, down to and through the intercooler, seems like a pretty good oil separator to me. Especially since oil would have to be blown uphill from the intercooler back to the top of the engine. In short, if only a little oil comes out there, then there probably isn't much for a catch can to collect.)

Just my take on this for what it's worth.

Whoops. I should correct something.

In the original write-up, it looks like writer is removing the PCV cover and stock PCV, and is screwing a new PCV in the threads for the cover, NOT for the PCV. In that case the little passageways to the intake ports would not be open at the atmosphere. Instead they would be linked with the passage from the oil separator, upstream of both the high side check valve and the low side PCV. Not good. So of course he suggests that the passageways to the intake ports should be closed.

My solution above might not work with this new PCV approach. That would depend on how well one could seal the passage to the intake ports while keeping the passage from the oil separators open.