[dzenno]

Originally Posted by Former_Boosted_IS

Have you considered a digital output/log? It is very accurate.

I have but it'd require cutting/splicing of the digital LC-1 output and I didn't want to do that as analog is more accurate anyway...

Sorry vasillalov...back on topic..

[Rob@RBTurbo]

That Big Tom catch can appears to be the fire!! Good job!! (I want one!!)

But, you need to get that check valve back in there. Its needed as when the intake manifold (post throttle body blade) is lower vacuum than pre-throttle blade... The secondary check valve opens and that one is supposed to close. So in essence you are creating some sort of vacuum leak at idle and ver low loads without that check valve in place. Aside for that, looks amazing.

As for the secondary check valve, it's supposed to close when the post TB blade pressure is higher than the pre-TB blade pressures (ie. Under boost and mild engine loads). At this point the check valve you ommited is to open and is essentially what you have in your setup.

Can anyone locate this secondary valve? It's in the diagrams but I havent had a moment to tear my car down to find it. I have concerns it may need replacement after time, and if it leaks under boost it will cause the turbos to pressurize the crankcase.

Originally Posted by dzenno

Oh yeah, what happened with the checkvalve? Don't see it there...

[EastBayE90]

I wonder if a simple inline airflow meter would be enough to test flow in the OCC lines. That could test for flow before and after the CC to see if there is a flow restriction. Then possibly just use a simple vacuum gauge with a T fitting inline with the OCC to test for loss of vacuum before and after the OCC. With a long enough vacuum line on the gauge you could even read pressure in the PCV system under load while driving. This could actually get some test results on the forum about these OCC's and it would no longer be speculation but hard facts.

This is what I'm envisioning, but this one from amazon I think would not be able to measure enough flow it looks pretty small. .7-7.5 cfm seems like not enough.

Inline air flow meter
http://www.amazon.com/General-Purpos...879065&sr=8-10

[dzenno]

Originally Posted by RobBeck

That Big Tom catch can appears to be the fire!! Good job!! (I want one!!)

But, you need to get that check valve back in there. Its needed as when the intake manifold (post throttle body blade) is lower vacuum than pre-throttle blade... The secondary check valve opens and that one is supposed to close. So in essence you are creating some sort of vacuum leak at idle and ver low loads without that check valve in place. Aside for that, looks amazing.

As for the secondary check valve, it's supposed to close when the post TB blade pressure is higher than the pre-TB blade pressures (ie. Under boost and mild engine loads). At this point the check valve you ommited is to open and is essentially what you have in your setup.

Can anyone locate this secondary valve? It's in the diagrams but I havent had a moment to tear my car down to find it. I have concerns it may need replacement after time, and if it leaks under boost it will cause the turbos to pressurize the crankcase.

I've tried to decipher the location of this 2nd checkvalve in the PCV system a few times too and to no avail..if anyone knows where it is and how to get to it please please let me know

An easy test I've read about that would test the PCV system on our cars is to basically take a rubber glove or even better say a balloon, take the oil cap off and put this on top and see if it starts getting sucked in (vacuum) or blown up (positive pressure). Vacuum would indicate proper PCV operation, ballooning would indicate a problem/clog. The absolute best would be to put a boost/vacuum gauge there and see but the diameter is too wide for anything I have for a vacuum gauge..

what do you guys think?

[Rob@RBTurbo]

That's ok while idling, but kind of hard to do when driving or more importantly when under high boost. If that secondary check valve is "failing" this test would have to be done on the dyno to capture. Best bet is to locate and bench test the pressure holding capabilities of the secondary check valve... And to keep both check valves in place if the intention is to run the system as it was designed.

[dzenno]

Originally Posted by RobBeck

That's ok while idling, but kind of hard to do when driving or more importantly when under high boost. If that secondary check valve is "failing" this test would have to be done on the dyno to capture. Best bet is to locate and bench test the pressure holding capabilities of the secondary check valve... And to keep both check valves in place if the intention is to run the system as it was designed.

One thing I want to let you know is the checkvalve that we "know" about, the one the OCCs are hooked up to, is not as strong as I thought and doesn't provide a great seal from the other side. I could easily just blow air the opposite side by just blowing out of my mouth into it. I did this on a brand new piece that I put in yesterday when I pulled out my BSH can.

[Rob@RBTurbo]

Yeah, that's what Im afraid of... but that is "ok" for that one. Hopefully the other one is much stronger as it should be completely sealed and airtight up to approx 25psi and if it's not it needs upgraded.

[dzenno]

Originally Posted by RobBeck

Yeah, that's what Im afraid of... but that is "ok" for that one. Hopefully the other one is much stronger as it should be completely sealed and airtight up to approx 25psi and if it's not it needs upgraded.

When this other checkvalve opens, where does it release pressure as per the diagram? And then, when it closes, where does it block off? Can you post a link to this diagram please? I'll take it with me to the shop tomorrow so we can track it down..

I'm afraid this checkvalve isn't replaceable and is just built into the valve cover some way as I couldn't find a part number for it on realoem.com...

[vasillalov]

wait wait... Let me get this straight.... You guys are saying that the stock check valve may not be strong enough to prevent boost from pressurizing the crank case on tuned engines, correct? If that's the case, then why don't we just cap the port on the intake tube?

[Jeff@TopGearSolutions]

Originally Posted by dzenno

^^^^^^^ sweet! Now that's an n54 OCC setup I really like! Great job Tom!!

Originally Posted by cn555ic

Big Tom...please list the parts that were needed and also where to buy the BIG TOM CATCH CAN!!!

[dzenno]

Here's a screenshot right from the N54 engine mechanics PDF in the sticky:



Not sure if its the drawing BUT take a look at where 1 is indicated. It's actually right before the elbow tube that has a pipe on it that goes to the rear intake pipe. So it seems that the checkvalve is actually NOT what we think it is even though I looked at that piece yesterday and there definitely was a checkvalve right in there...wtf, I'm confused now...is the checkvalve in the elbow part that sits on top of this outlet (which is what I think it is) or is it before the elbow piece???

1 & 3 is for the two checkvalves..they both seem to be right next to each other..."1" is the one that shoots out air with oil vapours into the rear intake pipe (or the OCC/breather if you're running it)...this happens under boost...

where does "3" come into play (the other checkvalve)??

[Joshboody]

Originally Posted by Zaaa

I will restate the fact that while I had the BSH OCC installed I was experiencing a rough, lumpy, unhappy sounding idle. Since I've taken it out and put the stock tube back in, everything is smooth and happy. Coincidence? Maybe. But I don't think so. For now I will just be accepting blow-by until someone comes up with a proper solution

this has nothing to do with a OCC... only used under boost

Originally Posted by Big Tom

You will get vaccum from the crankcase regardless if the checkvalve is there or not.

My theory is that this checkvalve is there to prevent the boost spike coming from the DV's.
...and I'm using BOV's so I will not be affected by this issue.

The vacuum is not from the cc, but other side of the pcv system inside the cylinder head cover (off boost)

Originally Posted by RobBeck

That Big Tom catch can appears to be the fire!! Good job!! (I want one!!)

But, you need to get that check valve back in there. Its needed as when the intake manifold (post throttle body blade) is lower vacuum than pre-throttle blade... The secondary check valve opens and that one is supposed to close. So in essence you are creating some sort of vacuum leak at idle and ver low loads without that check valve in place. Aside for that, looks amazing.

As for the secondary check valve, it's supposed to close when the post TB blade pressure is higher than the pre-TB blade pressures (ie. Under boost and mild engine loads). At this point the check valve you ommited is to open and is essentially what you have in your setup.

Can anyone locate this secondary valve? It's in the diagrams but I havent had a moment to tear my car down to find it. I have concerns it may need replacement after time, and if it leaks under boost it will cause the turbos to pressurize the crankcase.

this check valve is inside the cylinder head cover i believe. It is possible that the on boost side could have 2 check valves, one inside the valve cover to close the boosted pcv side and one for DVs like Big Tom mentioned. I remember the BMW pdfs showing both check valves inside the head cover.

EDIT: see Dzenno's post

[Rob@RBTurbo]

Under boost (or anytime post TB pressures exceed pre TB pressures), this secondary "mystery" valve CLOSES and needs to be sealed tight or we will turbocharge the crankcase (which will in turn be evacuated by the "known" checkvalve but will likely compromise the cyclonic separators functionality as well). When pre TB pressures exceed post TB pressures, it opens and the vacuum in the intake vents the crankcase (at these times the OCC will not do anything, which isnt that big if a deal as this is at idle and very low loads where there's not much blowby anyway).

Originally Posted by dzenno

When this other checkvalve opens, where does it release pressure as per the diagram? And then, when it closes, where does it block off? Can you post a link to this diagram please? I'll take it with me to the shop tomorrow so we can track it down..

I'm afraid this checkvalve isn't replaceable and is just built into the valve cover some way as I couldn't find a part number for it on realoem.com...

[Rob@RBTurbo]

Dzenno, yes #3 is it (the pressure restrictor). Hopefully this pressure restrictor is a good design that doesn't leak at high boost. We need to figure out how to interface with this pressure restricting check valve to make sure that it seals under high boost and isn't degraded over mileage. Seems it could very easily degrade over time.

[dzenno]

Originally Posted by RobBeck

Under boost (or anytime post TB pressures exceed pre TB pressures), this secondary "mystery" valve CLOSES and needs to be sealed tight or we will turbocharge the crankcase (which will in turn be evacuated by the "known" checkvalve but will likely compromise the cyclonic separators functionality as well). When pre TB pressures exceed post TB pressures, it opens and the vacuum in the intake vents the crankcase (at these times the OCC will not do anything, which isnt that big if a deal as this is at idle and very low loads where there's not much blowby anyway).

If this part is built right into the valve cover what do you guys suggest in that case?

[Rob@RBTurbo]

Doesn't matter if it's in the valve cover to test it (provided there's an interface). However if it's tested to be "insufficient"... Well then looks like the cover has to come off to remedy.

[dzenno]

Originally Posted by RobBeck

Doesn't matter if it's in the valve cover to test it (provided there's an interface). However if it's tested to be "insufficient"... Well then looks like the cover has to come off to remedy.

Ok, let you know soon, taking off valve cover Saturday afternoon..

[EastBayE90]

Was able to find this picture on ALLDATA of the inside of the valve cover but still doesn't show much. And I've have had a really hard time finding pictures of the check valves on ALLDATA.




Uploaded with ImageShack.us

[dzenno]

I don't see anything resembling a checkvalve there...anyone?

[vasillalov]

I think my Bentley manual had some information and pictures on this. I will try to find it this evening after work and post it.

[marconi118]

Originally Posted by RobBeck

That Big Tom catch can appears to be the fire!! Good job!! (I want one!!)

But, you need to get that check valve back in there. Its needed as when the intake manifold (post throttle body blade) is lower vacuum than pre-throttle blade... The secondary check valve opens and that one is supposed to close. So in essence you are creating some sort of vacuum leak at idle and ver low loads without that check valve in place. Aside for that, looks amazing.

As for the secondary check valve, it's supposed to close when the post TB blade pressure is higher than the pre-TB blade pressures (ie. Under boost and mild engine loads). At this point the check valve you ommited is to open and is essentially what you have in your setup.

Can anyone locate this secondary valve? It's in the diagrams but I havent had a moment to tear my car down to find it. I have concerns it may need replacement after time, and if it leaks under boost it will cause the turbos to pressurize the crankcase.

The "secondary valve" is in the valve cover next to where the OCC connects, there is a small round cover you can remove by unscrewing it with a flat key. I obstructed this valve with a simple piece of silicone pipe, so that no blow by will go directly in the manifold and coat the valves....

[dzenno]

Originally Posted by marconi118

The "secondary valve" is in the valve cover next to where the OCC connects, there is a small round cover you can remove by unscrewing it with a flat key. I obstructed this valve with a simple piece of silicone pipe, so that no blow by will go directly in the manifold and coat the valves....

So in that case it's always closed? How long have u been running it that way? Wonder what the effect of closing it like that is?