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· Seek to understand,^Value
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Discussion Starter · #1 · (Edited)
EDIT:

  1. On the M54 CCV, the vacuum port is closed off with an endcap
  2. On the M52, the vacuum port of the CCV provides vacuum for the fuel pressure regulator
  3. On the M62, the vacuum port of the CCV provides vacuum for the sucking jet pump
-----
I'm curious WHERE the vacuum hose goes for the E39 CCV valves that do NOT have their CCV vacuum port plugged.

My theory (which is just a guess) is that this plugged port #9 on the back of my 2002 M54 engine is where the CCV vacuum hose 'would' have gone had it been in place.
- Engine => Vacuum control => AIR PUMP F VACUUM CONTROL

That plugged port is also shown as #17 in this diagram:
Engine => Intake manifold => Intake manifold system

Do you think this plugged port is what WOULD have been connected to the CCV if the CCV port wasn't also plugged?


NOTE: There is a typo in the caption; it should be "BTW, note the cracked condition of that endcap" (since replaced as explained here):
- How to locate all the vacuum hoses in the E39 engine bay
NOTE: We found the part number & size for the endcap over here:
- M54 vacuum hoses ... what diameter ... what brand ... what material ... what length?
NOTE: See also a thread which asks what the vacuum port on the CCV actually does:
- CCV vacuum hose important?
 

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suscribed

I am curious about this as well.
My M52TU uses this, but not my M54. M54 has more CCV issues and mayo. I worry about hydro-locking the M54 every winter.
I recall a post where someone applied intake vac to this port on CCV of M54 and achieved less oil consumption, which I experience on M54 and NOT with the M52. Curious if it would run cleaner in winter, but am afraid to mess something else up with balance of M54 harmony.
I will try to research this after work.
 

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why does it matter?
if youre worried about crankcase valve issues in the cold, just change your oil more often and make sure you drive your car a little harder. you merely need to get the oil to a temp in which the water naturally will vaporize.
 

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It matters to me

why does it matter?
if youre worried about crankcase valve issues in the cold, just change your oil more often and make sure you drive your car a little harder. you merely need to get the oil to a temp in which the water naturally will vaporize.
I suspect this may be why the M52s don't have the same issues as the M54 CCV. Another difference is the cooling system design. M54 is designed for hotter bottom end (reducing friction) and cooler head (increased combustion efficiencies). Perhaps BMW eliminated this vac hose for other reasons and the result is decreased CCV performance. Rather than blaming this issue, they decide to throw insulation at the problem and blame it on cold weather and ethanol gas (which I'm sure doesn't help with condensation). I'm an engineer for a large corporation and I am surrounded with instances when business politics and accounting can really impede otherwise good products.
Daily commute for M54 is 30 minutes each way mainly hwy speeds. Oil is changed every 6k with M1 0w-40. I'm not from the "short drive cycle" / "high OCI" sample.
 

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Discussion Starter · #8 · (Edited)
why does this matter?
The more we learn what BMW was thinking when they designed the M54 engine, the better we understand our engines.

I recall a post where someone applied intake vac to this port on CCV of M54 and achieved less oil consumption
Exactly!

Perhaps, if we understand what port BMW originally intended to deliver vacuum to the CCV, and if we then apply that vacuum via that port, 'something' useful may result from the experiment.
 

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The vacuum port on the CCV valve went to the fuel pressure regulator on the M52 engines--the M54 engine the port is capped off-----on the M54 engines the fuel pre--reg derives vaccum from the small vac hose that goes into the air intake duct--right after the maff--along side of the vac hoes for the jet suck pump
 

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Is there anything wrong with trying to better understand the M54 engine?

The more we learn what BMW was thinking when they designed the M54 engine, the better we understand our engines.

Plus, the bonus is the more we learn, the more we find out what 'else' we can do with that spare vacuum port.

Who knows? Maybe we'll find a way to hook it back up to the CCV to suck out some of the accumulated mayo or to derive some other (originally intended?) benefit.

In fact, looking forward to the answer, I'm directly hoping that the answer to the question yields benefits due to our increased understanding of why BMW put a port on the CCV and then capped it off - and then ways for us to improve the admittedly problematic CCV system operation.
I didn't mean to sound so skeptical but in this case, I am a total skeptic. Nothing wrong with gaining a better understanding of our cars. I'm all for that. :thumbup: You ask some great questions, BB, but I don't think that this is the place to find the real answer to your question. I have yet to see a single real BMW engineer post on this forum. And while there are many capable mechanics and techs that do post, they would not be an accurate source as to why a technical change has been made to the M54 engine design. But my response to your question was "why does this matter". If someone posted a technical reason for the design change and identified the former connection point to the CCV, would you or anyone here seriously consider changing the design/operation of their CCV*? I mean, really? You would be making a change with little or no knowledge of the consequences. The M54 (as well as the complete line of BMW I6 engines) has long been renowned for their sophisticated engineering and high performance. However, is anything perfectly designed? Not a chance. Every design decision requires making tradeoffs during product development. When the CCV evolved, someone or a team assessed the pros and cons of leaving the design unchanged but for whatever reasons, opted to make a change. Without fully understanding all the considerations of that decision, contemplating unmaking that change because you think you might fix a different problem is both unwise and foolhardy. I'm all about improving the BMW design, IF you have an engineered solution (e.g. Vanos seals) that has been demonstrated to work. So to your original question: Yes, in this rare case, it appears that you are blowing smoke! :flame: (But that's just my opinion)

*I know Poolman modified his CCV but he has demonstrated a high degree of mechnical competence and has been a pioneer in other areas (Vanos) so he is somewhat of an anomoly.
 

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I didn't mean to sound so skeptical but in this case, I am a total skeptic. Nothing wrong with gaining a better understanding of our cars. I'm all for that. :thumbup: You ask some great questions, BB, but I don't think that this is the place to find the real answer to your question. I have yet to see a single real BMW engineer post on this forum. And while there are many capable mechanics and techs that do post, they would not be an accurate source as to why a technical change has been made to the M54 engine design. But my response to your question was "why does this matter". If someone posted a technical reason for the design change and identified the former connection point to the CCV, would you or anyone here seriously consider changing the design/operation of their CCV*? I mean, really? You would be making a change with little or no knowledge of the consequences. The M54 (as well as the complete line of BMW I6 engines) has long been renowned for their sophisticated engineering and high performance. However, is anything perfectly designed? Not a chance. Every design decision requires making tradeoffs during product development. When the CCV evolved, someone or a team assessed the pros and cons of leaving the design unchanged but for whatever reasons, opted to make a change. Without fully understanding all the considerations of that decision, contemplating unmaking that change because you think you might fix a different problem is both unwise and foolhardy. I'm all about improving the BMW design, IF you have an engineered solution (e.g. Vanos seals) that has been demonstrated to work. So to your original question: Yes, in this rare case, it appears that you are blowing smoke! :flame: (But that's just my opinion)

*I know Poolman modified his CCV but he has demonstrated a high degree of mechnical competence and has been a pioneer in other areas (Vanos) so he is somewhat of an anomoly.
Yeah, maybe it's best to not be so curious. Who likes learning about things they are interested in. Screw that. I NEED to think about these things. It beats thinking about hydro ilocked engine. It's a poor design that needs a solid solution. For some reason, less problematic on E36 and M52s. I am curious.
Perhaps your image of this forum is correct, but it is surely
unwise to promote a "don't bother to think about why" attitude here and leave intelligent minds with poor initial impressions of this forum. Note my thread count.
 

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You need to reread my thread. I am not promoting a "don't bother to think about it" attitude. My concern is what BB is suggesting when she says "Maybe we'll find a way to hook it back up to the CCV". What I am saying is don't even consider a radical modification of your CCV :yikes: unless you really know what you are doing. Clearly, Poolman knew what he was doing. But I don't see anyone repeating his CCV solution (the oil catch can). BB has been on this forum for awhile and she has never demonstrated a willingness to step beyond her mechanical capabilities (which is wise). Neither have I, for that matter. So now she is contemplating a redesign of the M54 CCV system? I simply don't recommend it. In my opinion, anyone that thinks they know more about these cars than the factory has an overinflated opinion of their own knowledge and abilities. These cars are very sophisticated machines. And yes, they are far from perfect. The collective experience of this forum's owners is a huge asset but nothing said here should be taken as gospel. This is the Internet, where anyone can say anything! :rofl:

The Vanos seals is a great example of a major problem applicable to all M54s, M52s, etc. that has been modified by the aftermarket. Beisan Systems diagnosed the problem, reported it to BMW (who ignored them) so they redesigned the seals and wrote up a detailed DIY to replace them. Even with the glowing remarks from people who did this job (Poolman), it still took me awhile to muster up the willingness to open up my engine to do this. If you do anything to your car, do this, for the performance improvement.

WRT to the CCV specifically, there is no aftermarket solution other than the insulated hoses. Consider the scope and magnitude of the CCV problem before you consider any corrective action you may regret. First, do a search to determine how many hydrolocked engines have occurred due to CCV issues. It is not many (more common on the X5). Second, a failing CCV is rarely an immediate catastrophic event, unlike a cooling system or DISA valve failure . A failing CCV system typically begins with increased oil consumption and a smokey exhaust. Can it fail catastrophically? Yes as in Doru's case. But it can be corrected by simply (actually a PITA) replacing the CCV and hoses. Modifying your driving habits can help to reduce the likelihood of a problem. All in all, the CCV is flawed system but not what I would consider a major deficiency in the M54 design. I personally feel this is the best designed engine I have ever owned.

My advice is simply this: "A (wo)man's got to know his limitations". Learning more about something is one thing. Doing something about it is an entirely different matter. Just one guys opinion. :roundel:
 

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Discussion Starter · #15 · (Edited)
The vacuum port on the CCV valve went to the fuel pressure regulator on the M52 engines
Interesting! Very interesting!

I am 'not' attacking your assumption by asking the clarifying questions below ... but if that statement above is true, everything I 'thought' about the CCV vacuum source is wrong.

So ... I 'must' ask ...

If the hose on the M52 goes from the CCV to the fuel pressure regulator, would I be correct in assuming the DIRECTION of air flow MUST be FROM the fuel pressure regulator TO the CCV?

If so, having the CCV be the 'source' of vacuum is directly the opposite of the user-annotated (mostly by cn90 and me, IIRC) diagrams sprinkled all over the place.

For example, look at the pictures & diagrams here:
- How to test the crankcase ventilation (aka CCV, CVV, PCV, CPV, & OSV) pressure regulating valve system (1)



Both the picture above (from cn90) and the diagram below (annotated by me), assume the CCV vacuum port is connected to a 'vacuum source'.


So, to move forward, we have to clarify how the M52 worked before we can begin to understand the M54.

QUESTION:
Q: In the M52 engine, what is the DIRECTION of air molecules in that vacuum hose?

Said in other words:
Q: In the M52 engine, which end of the hose is the vacuum source (i.e., the CCV or the fuel pressure regulator)?
 

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I don't know anything about the M52 engine vacuum routing, but I may be able to answer you question.

I still have the CCV I removed a few weeks ago. I took it apart, so I think I can explain how it works.

The bottom cone shaped part is a cyclonic separator. If you look at the entrance of the vent tube, you'll see that it enters the cone at a tangent. The blow-by gasses and oil hit the sides of the cone forming a vortex. The oil droplets are thrown against the side of the cone and fall into the tube that drains to the dipstick. The gasses are forced through the center of the vortex up through the "L" shaped tube that connects to the upper part of the CCV.

The connecting line that connects the upper part of the CCV to the manifold supplies a vacuum. The upper part has a diaphragm and spring. When there is a high vacuum at idle, the diaphragm moves to close off the connecting line. When the vacuum drops at high engine speed, the spring pushes the diaphragm back allowing the gases in the cyclonic separator to flow into the manifold. I think this is typical design for a PCV system because it allows blowby gases in the manifold at high engine speed and blocks the blowby gases at idle.

The "L" shaped tube has the nipple. When the diaphragm in the upper part is open, the nipple will have the same vacuum as the manifold. When the diaphragm closes, the "L" shaped tube is closed off from the manifold vacuum, so the nipple will be at the same vacuum as the crankcase.

So it seems likely that the nipple was indeed a vacuum source for a fuel pressure regulator. At high engine speed, a vacuum would be applied to the FPR to increase fuel flow. At idle, the high manifold pressure the closes CCV diaphragm and no vacuum would be applied to the FPR through the line connected to the nipple.

If you connect that nipple to the manifold, it will pull blowby gases into the manifold at idle. Because the engine speed is low, that may not be a good idea. .
 

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Discussion Starter · #18 · (Edited)
I think I can explain how it works.
That was a wonderful explanation! (As was the previous one about the 'blanking cap' over in your Bimmerforums.co.uk reference.)

To ensure value added, I will add both explanations to the annotated pictures in order to further leverage those revelations to other CCV-related threads (& get the word out).

The most interesting comment was this one:

it seems likely that the nipple was indeed a vacuum source for a fuel pressure regulator
If the CCV center-section port is a vacuum 'source', that changes everything about this thread!

Besides making all the diagrams wrong in an instant, it also instantly negates the 'need' to find the 'missing' vacuum port on the M54!

Believe it or not, a key question might be the shape of your F connector!

You may wonder why I ask that ... and I'll explain in due time ... but first, may I ask if the F connector on vacuum-equipped CCVs is actually L shaped as shown in the diagrams in this recent thread?
- Correcting the F-connector errors in the realoem diagrams (1)

M54 engines with end caps need those end caps replaced to prevent vacuum leaks.
It looks like the M52 is the only E39 to use this CCV vacuum source?
Apparently on the S62, this CCV-derived vacuum port does not exist.
On the M54, it seems degradation of this endcap can indeed be a source of vacuum leaks.

In fact, there is a simultaneous quest to find & replace the two, three, or maybe even four endcaps over here:
- What are the vacuum endcaps in the E39 engine (1)

1) #17, 7mm (between 17/64" & 19/32") endcap for the M54 engine rear vacuum port.
2) #15, 3.5mm endcap (between 1/8" & 9/64" ID) for the CCV valve vacuum port.
3) #15, 3.5mm endcap (between 1/8" & 9/64" ID) for the air pump vacuum port if you don't have an air pump (see details from Steve on this below).
4) Some exhaust systems seem to have a 7mm endcap?
Q: In the M52TU engine, what is the DIRECTION of air molecules in that vacuum hose?
A: Molecules move TOWARD the CCV (from the fuel pressure regulator).

Q: In the M52TU engine, which end of the hose is the vacuum source (i.e., the CCV or the fuel pressure regulator)?
A: The CCV, for this question, can be considered the vacuum source (not the FPR).


REFERENCE: M54 engines - guide to finding vacuum leaks
REFERENCE: Steve530 in this thread

REFERENCE: Detailed DIY for Crankcase Ventilation Valve Overhaul for the M52TU Motor
 

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Blue Bee--told ya before--don't second guess me --when I had problems with oil usage--one of the things I to make the fix with was--I ran a vac line from the ccv port we are referring to and then hooked the other side to one of the ports at the back of the intake manifold. This helped some, but not enough. I ended up with my oil catch can and putting the complete crankcase in a controled vacuum utlizing a common PVC valve from a big block Ford--Ford products work well everywhere
 

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Discussion Starter · #20 ·
Blue Bee--told ya before--don't second guess me
:) We are thinking the same thing but you got the jump on me, by, oh, I don't know, a few years probably!

As soon as I saw an empty unguarded undefended port, my mind wanted to make good use of that otherwise-wasted vacuum source for my purposes quicker than Nancy Pelosi could wrap her hands on a new source of revenue to be squeezed out of the hard-working people!

The thread you're referring to is probably one of these, which I will read:


I ran a vac line from the ccv port we are referring to and then hooked the other side to one of the ports at the back of the intake manifold
I'm going to have to 'slowly' read (and re-read) your solutions ... but may I ask the first obvious (perhaps dumb) question that arises?

Assumption:
Since we now know that the ccv vacuum port was intended to be a 'source' of vacuum for the fuel pressure regulator ... (i.e., the movement of molecules was intended to be INTO the CCV valve)...
Question:
What is the logic of benefits from reversing the flow from that of the initial design?

Note: I'll first read for the answer in the threads ... but that's the first question I have since I now realize the CCV was never designed to be attached to a vacuum source at that nipple in the middle of the CCV.
 
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