Oil consumption after CCV replacement

[kenndoggy]

I still say the TRM exhaust checkvalve I linked 2 pages ago would be more ideal. Especially under hard throttle situation, you'll ALWAYS be pulling a vacuum on the crankcase, which will help reduce blowbye, and help promote ringseal at WOT.

[bmwdirtracer]

Oh, goddammit, kenndoggy! That's SO politically incorrect, and I really do like it so much; can I get partial credit for mentioning it?

As I understand it, drag racers find significant power by pulling a vacuum on their sumps, even justifying an engine-driven vacuum pump to provide it. I really don't understand why BMW's made it so very complex though: it seems to me that the early designs were simplistic and effective, with nary an issue.

[kenndoggy]

Oh, goddammit, kenndoggy! That's SO politically incorrect, and I really do like it so much; can I get partial credit for mentioning it?

As I understand it, drag racers find significant power by pulling a vacuum on their sumps, even justifying an engine-driven vacuum pump to provide it. I really don't understand why BMW's made it so very complex though: it seems to me that the early designs were simplistic and effective, with nary an issue.

I'd plumb a catchcan inline though. You COULD put the bung pre-cat if you are really concerned about emissions, but I wouldn't want to risk damage to the cat. BMW cats aren't exactly cheap.

[02Pilot]

If the problem we were chasing was oil consumption at WOT, I'd be looking at a solution like that, kenndoggy, but it is on deceleration, where vacuum in the exhaust would be minimal and thus not as effective.

Dirtracer, the ports are open and capped. You have to move a few things to get to the one on the CCV, but the one on the manifold is easily accessible just reaching around the back corner (there are two, one larger and one smaller; you want the smaller one). It's an extraordinarily simple thing to try for those who have similar issues, non-invasive, and fully reversible.

It is amazing that BMW made the system so unnecessarily complicated (there has to have been some perceived advantage to this complication - my guess is they were chasing some tiny fuel efficiency gain), and that it is requiring such effort to track down what's actually going on in the system. That's why I made sure I had vacuum measurements from the crankcase with the new setup before I posted about it: we need more hard data. Even with only a few possible culprits, the interaction of systems makes it complex. Only good solid data is going to help sort out the mess. I appreciate your efforts to add to the sample, though it seems to be a frustratingly functional system in your corner of the world.

The idea that it could be a problem with the internal design of the valve related to rubber compound or something similar is intriguing, though I think it is beyond my ability to test. Ideally, you'd need a new CCV and an old one, and the ability to test the durometer and elasticity of the diaphragm. It would be interesting to see how it might be affected by cold temps.

[02Pilot]

I should also have mentioned somewhere in my long-winded ramblings that during testing I also took the CCV out of the loop completely and the oil burning condition remained unaffected, thus eliminating the CCV as the primary source of my problem. Thinking back to the original problem, this led me to the idea that removing a failed CCV (causing high vacuum in the crankcase) and replacing it with a functional one (controlling the crankcase vacuum at a very low level) may have inadvertently exposed another issue, be it ring flutter or leaking valve seals or both. But it would appear on the surface that New CCV = Oil Consumption, when in fact the cause lay elsewhere.

For the pros still following this, do you see a lot of M54s with high mileage (say 120k+)? If so, what would you say the incidence of oil consumption is in these examples?

[mahmoudh]

O2Pilot,
Thank you for this great news. I have not been able to work on the 2001 530i but am very encouraged and will try this out if it warms up this weekend with factory disptick tube.
I will also verify whether my M52B28 has this vaccum hose connection and if so it may explain why it consumes no oil compared to the 2001 M54B30 consuming 1 qt/600 miles.

Mahmoud

Mainly, I'm just going to watch this very interesting thread, with a hope to finding out whether it'd pure dumb luck that I can't find a similar issue in this very mild climate..

Is the emissions standard in Hawaii differenent from mainland USA? Like CA is different from NY? If so are the vehicles any different in terms of vaccum and pressure (hose and other parts included)

[02Pilot]

O2Pilot,

Is the emissions standard in Hawaii differenent from mainland USA? Like CA is different from NY? If so are the vehicles any different in terms of vaccum and pressure (hose and other parts included)

I don't think there's any difference in the crankcase vacuum spec or the CCV plumbing; I've never seen it referenced in parts diagrams.

[bmwdirtracer]

Hawaii, like most other states, has no emissions standards of it's own. Cars sold here are "49 state" cars, with the same equipment as those.

As I understand it, emissions tests are only federally required in those counties which have a smog/dirty air problem, and there are places on the mainland which have no testing. Hawaii certainly won't have any issue with clean air standards, because however much smoke we make is instantly blown away by the daily trade winds.

(The rare exception is when we have a wind from the south-east, a few days a year. This breeze brings VOG, a nasty sulphur laden volcanic smog from the Big Island's volcano.)

But, lest you think this is a driver's paradise, be aware:
Our roads are generally terrible, and have absolutely ridiculously low speed limits. And the worst drivers on earth.

The State's governmental bureaucracy, especially as regards cars, is right up there with California or New York, as are taxes.

The police are rabid, when it comes to driving and automotive enforcement. Every month or so they go on a new binge to secure endless funds for the state. This week, it's loud exhaust and window tint, and they've given well over a thousand tickets during six days of enforcement -- in two small towns alone. (Maui has just over 100,000 people) It's particularly painful for those with dark (<35%) tint, because EACH WINDOW will cost you $267! One guy I know had $2100+ in fines, just for tint. Note that they say this is for safety - but suv's, vans and pickups are exempt. We have a seat belt law, but you can ride in the back of a pickup, or ride a bike without a helmet....


Sorry, off the subject...I now return you to your regularly scheduled programming, and the task of correcting BMW's overzealous ccv system.

3-6" of water is the accepted standard for crankcase vacuum on BMW's, prior to vacuum pumps and valvetronic anyway; those I have no idea. I really like my E28's CCV: a good baffling of the valvecover, one single hose, and a restrictive backwards rubber duct in the hose between air measurement and throttle body. Kind of makes me wonder why that wouldn't work on say, an E46....? My intake is not an oily mess, my crankcase runs the correct vacuum, and in fact, barring intake leaks, this has been true of every healthy M20 or M30 I've ever known.

I'm a fan of crankcase vacuum, but I really don't see why such a complex system is necessary. I understand that we have emissions laws never considered when M30s were built, but it really seems to me that the newer systems cause far more oil-burning than the earlier systems, so I wonder what effect a simple solution might have on emissions?

[02Pilot]

I can't imagine the emissions would be adversely affected in any significant way by using a simpler system. My modification is not having any negative impact on fuel efficiency, at least; I managed 31.3mpg over 100 miles of more-or-less steady driving immediately after doing it.

As to the complexity of the system, my speculation (and it's only that) is that the arrangement was intended to achieve a marginal improvement in steady-state cruising fuel efficiency by warming the intake charge with air pulled from the crankcase. I cannot think of another reason to have a distribution manifold very close to the head and a balance tube except to make sure that the intake charge was as warm and even as possible. Seems like a poor trade-off (in retrospect, at least), but manufacturers are looking for anything they can find these days to meet CAFE targets.

[mahmoudh]

I don't think there's any difference in the crankcase vacuum spec or the CCV plumbing; I've never seen it referenced in parts diagrams.

02Piot,
I also poked around and found country specific models but could not find anywhere that M54s used country specific parts so I will assume the plumbing for emission and vacuum is the same in all US at least.

Chris,
Thanks for the OT rant. Much appreciate the rare reality check on Paradise

Maybe someone can comment on whether the M54s had higher than normal oil consumption when new.

My 2001 M54 between 73K-110K miles consumed approx 1qt every 5K or so miles then became excessive the last 30K miles.

Could cold climate condensation be increasing deposit buildup in the engine and plumbing over time that eventually alters flow dynamics that then impact the pressure/vaccum balance at the CCV? (Assuming no leaks)

How about M54s in Southern Cal or Florida/Carolinas? Do they see increased oil consumption as they age or is their oil consumption similar to Hawaiian operated M54s?

[02Pilot]

The thing to note here is that a failure of the CCV does not appear to be directly responsible for the oil consumption I was experiencing. It appears to have been due to a combination of valve seals and rings, which were in turn exacerbated by the very low vacuum pull on the crankcase when the CCV works as designed. I suspect this is an issue of simple wear and degradation of the valve seals (a problem on BMWs going back to the 1960s) combined with some sort of peculiar ring and/or cylinder wear (I'd really like to know more about the piston and ring design of the M54) that does not manifest as blow-by under load (typical of worn rings) but instead allows the compression rings to lift and flutter when the cylinders are under vacuum (and at a high differential pressure to the crankcase). In other words, while the CCV is a failure-prone system, there is also the possibility that some higher mileage M54s are suffering from normal wear that, in combination with the design of the CCV and the engine internals, is causing oil consumption even with a fully functional CCV. Modifying the system to increase vacuum in the crankcase is simply a way to work around the issue.

[Leslie1234]

[IMG]http://www.**********.info/7.jpg[/IMG]

[bmwdirtracer]

Leslie's been a bad boy.

I wonder if an exhaust backpressure test might reveal some clue we've missed; I have seen a partly clogged cat kill rings. Maybe worth a quick test, to rule that out, if nothing else.

[02Pilot]

Could be, though I'd expect a clogged cat to cause a loss of power, which is not something I've experienced; the car runs like a top right up to the limiter. If it were bad rings in the traditional sense, I'd think the symptoms would be more conventional, i.e., loss of compression, blow-by and smoke at WOT. Nonetheless, maybe I'll fab up an adapter for the pressure gauge when I have a chance and see what's happening.

[mahmoudh]

The thing to note here is that a failure of the CCV does not appear to be directly responsible for the oil consumption I was experiencing. .... In other words, while the CCV is a failure-prone system, there is also the possibility that some higher mileage M54s are suffering from normal wear that, in combination with the design of the CCV and the engine internals, is causing oil consumption even with a fully functional CCV. Modifying the system to increase vacuum in the crankcase is simply a way to work around the issue.

I have always suspected lower vaccum at the CCV due to partially clogged distribution piece on intake manifold that connects to CCV but have yet to confirm.

I cannot help but worry that the oil separator is too small for this engine, especially higher mileage vehicles with increased blow by gases.

The diaphragm in a new CCV is less of a concern.

[02Pilot]

I have always suspected lower vaccum at the CCV due to partially clogged distribution piece on intake manifold that connects to CCV but have yet to confirm.

I cannot help but worry that the oil separator is too small for this engine, especially higher mileage vehicles with increased blow by gases.

The diaphragm in a new CCV is less of a concern.

Well, I can tell you that my distribution piece is 100% clear and not impeding anything. I think that, given the very low vacuum specified, the area of the 6 orifices exiting the distribution piece into the manifold are more than sufficient; after all, I've got a single smaller orifice managing to pull the crankcase down to 10inHg (or roughly 136inH2O) relatively quickly. Assuming it's not blocked (a big assumption on some engines, admittedly), I don't think the distribution piece design is a major issue here.

We're going to see about the oil separator, as my modification is pulling a lot more crankcase vapors through it than it was designed for. It may not be removing every last drop of oil, but even with the substantially increased flow, it's not pulling enough into the intake to cause any sort of oil smoke. We'll have to wait any see what overall consumption looks like as I put more miles on the car with the modification in place. I do think it may be smaller than would be optimally effective, but then again, given that it's a cyclonic separator, the higher velocities of my arrangement might actually help separate the oil.

[bmwdirtracer]

Holy sh*t, you're pulling that kind of vacuum on the crankcase? Now I'm scared for you. What I can't begin to understand is how the early cars (think M30) arrangement could possibly have delivered such little vacuum, when your is so, um, excessive, through a tiny orifice?

In consideration, it would seem that the "flap" in the intake bellows of the earlier cars must close off, nearly completely, at higher vacuums, and open only at lower vacuums, like WOT? Perhaps incorporating this sort of arrangement in your experiments might be worth a look?

Maybe Jim Levie will have a better clue, vis-a-vis the older cars. I know he's done some research, and runs a catch can to keep oil vapors out of his intake.

[02Pilot]

While it's a lot more vacuum than the spec, it's really not that much relative to what it seems can be run without a problem. First off, it's only 5psi. Second, it seems that vacuum pumps in racing applications can go as high as 15inHg before builders recommend dry sump lubrication. Third, I'm only touching 10inHg on very rare (long periods of deceleration) occasions that involve no load on the engine. The vast majority of the time, and under basically any load on the engine, vacuum is at or near spec; even at idle it tops out at 5inHg.

It would be interesting to look at the arrangements in the older cars. My recollection of my old M30's setup is vague at best. I do recall that it had the large line from the valve cover hooked into the intake tract before the throttle plate, which is of course a much more conventional arrangement.

I know Jim was active earlier in this thread. I am, of course, happy to hear his thoughts on this if he wants to chime in.

[e30hijinks]

My 2002 330i manual appears to consume TONS of oil on high rpm decel (say spirited driving a for a couple of hours) and consumes about 1 qt every 1k miles on normal driving. It's very well maintained (except it has the original CCV @ 120k miles) and has no codes or apparent vacuum leaks. I too blame the valve guide seals as I do have puff of smoke on acceleration after a period of deceleration.

but you're saying your valve guide seal replacement didnt work? (which BTW is genius if done without removing the head! any pics or more info on how exactly this was done???) I would certainly buy a tool if you provided one. I haven't dived too deep into the motor but would I be right in assuming the cams/caps? would have to come out first?

Apparently the later 2003+ M54s have double valve guide seals. I'm not sure if this has been confirmed.

[02Pilot]

Yes, the cams and carriers have to come out. It is still a labor-intensive process, but better IMHO than the risks associated with head removal on the M54.

Replacing the valve guide seals had a noticeable effect; as I mentioned, engine braking is notably stronger than it was before the replacement. This tells me that the valve stems are sealing better. However, it did not resolve the oil consumption. This is not to say it wouldn't resolve yours; some have had good success with it. But in my case, oil was still being consumed. My speculation on the ring flutter issue is just that, but the resultant drop in consumption after adding additional vacuum to the crankcase is consistent with it being a factor.

If it were me, I'd consider trying the modification I described, paying close attention to the caveats I noted. I would replace the CCV and the dipstick guide tube at the same time.

[e30hijinks]

Forgive me if I don't understand (I'm a visual learner) so you connected a piece of rubber line from the CCV to a nipple on the intake manifold? If you did post pics, i won't be able to see them cause my work computer is firewalled. But if you didn't could you post a pic or maybe a realOEM diagram showing the two connections?

So it seems that engine brake basically causes ring flutter. I wonder if i used my brakes to slow the car rather than the engine if I'd all but eliminate consumption?

I also wonder if this can explain why later M54s typically don't experience high oil consumption? seems to be inherent to 01/02 models.

[02Pilot]

Lots of unknowns in this to be sure. The early M54s being more prone to consumption could simply be a matter of age and mileage, or it could be a design difference. Using your brakes would have no appreciable effect, as that would not change the vacuum in the crankcase whatsoever.

I don't have any pictures, and RealOEM won't show it, as it's not factory. It's simply a small diameter hose from the unused nipple on the CCV between the oil separator and the valve connected to the small capped nipple on the back of the manifold. If I can get a picture I'll post it, but it's snowing here right now, so it might be a while.

[Struble2010]

Thanks for your hard work [IMG]http://www.**********.info/7.jpg[/IMG]

[e30hijinks]

Lots of unknowns in this to be sure. The early M54s being more prone to consumption could simply be a matter of age and mileage, or it could be a design difference. Using your brakes would have no appreciable effect, as that would not change the vacuum in the crankcase whatsoever.

I don't have any pictures, and RealOEM won't show it, as it's not factory. It's simply a small diameter hose from the unused nipple on the CCV between the oil separator and the valve connected to the small capped nipple on the back of the manifold. If I can get a picture I'll post it, but it's snowing here right now, so it might be a while.

Thanks. Appreciate it. But what I meant by braking is instead of slowing the car by downshifting and letting the engine brake from redline (aggressive engine braking) i meant just using my brakes exclusively. In other words, no high-rpm deceleration.

And as far as realOEM, I know it's not a factory mod you did, what I meant was circle the area on a diagram or a pic showing where you attached the other end of the line to on the intake manifold. i.e., google an image of the E46 intake manifold and circle the area you used. That's all

[02Pilot]

Thanks. Appreciate it. But what I meant by braking is instead of slowing the car by downshifting and letting the engine brake from redline (aggressive engine braking) i meant just using my brakes exclusively. In other words, no high-rpm deceleration.

And as far as realOEM, I know it's not a factory mod you did, what I meant was circle the area on a diagram or a pic showing where you attached the other end of the line to on the intake manifold. i.e., google an image of the E46 intake manifold and circle the area you used. That's all

No matter how you slow the vehicle, if the CCV is working properly, there will be no appreciable change in vacuum in the crankcase. The design of the valve is such that it is intended to regulate continuous vacuum (i.e., within 3"-6" H2O spec) under all conditions.