DIY Solution to M54-M52TU CCV problems

[Xelo]

I must revive this thread upon new findings regarding the amount of vacuum the M54 pulls after this modification.

In latest SIB 110308 BMW states the amount of pressure/vacuum inside the M54 crankcase must be ~16 mBar (that is 0,48inHg). As measured while using the FRAM FV345 PCV valve, the vacuum is 12-15 inHg (or +500mBar). That is over 30x the limit the engine was designed for, this is insane!

And this amount of vacuum is at idle ! Please imagine what letting off throttle/decelerating at 3-4-5K RPMs will do to the level of vacuum
This will no doubtly damage seals/orings inside and deprive the oil pump of oil, lowering oil pressure for brief moments on decelerations.

I have not met another engine in the world where upon opening the oil cap that much vacuum is present. This is wrong and must be addressed as this modification transforms a Closed Crankcase Ventilation system into a Positive Crankcase Ventilation system, but without all the elements needed for such a PCV system to work.

Inside classic PCV systems/engines, there is a continuous air circulation inside the crankcase because there are 2 holes letting the crankcase breath: first one lets the blowby exit being sucked by the intake through the PCV and the 2nd one lets fresh filtered air inside the crankcase in order to: 1) limit the amount of vacuum being built 2) properly vent all areas of crankcase in a wide range of engine RPMs
Usually this 2nd hole sucks air from the intake downstream (after) of filter/MAF/MAP but before (upstream) throttle - where the vacuum is low when throttle is closed.

By removing the CCV (OK), plugging the dipstick drain hole (not OK) and rerouting the crankcase blowby venting directly into the intake (OK) you have designed an incomplete PCV system. One has to allow the block/crankcase to be vented with fresh air from a clean source otherwise it would be like sucking air from a plastic bottle: something/somewhere will colapse and those will be either your VCG or rear main seal.

By venting the block through a 2nd hole you are punching a hole in that plastic bottle you are sucking air out of: while the sucking is still there, the bottle will not collapse anymore as some small venting/air is let in keeping it vented.

If this worked for some of you it does not mean is a right thing, the engine was not designed for this amount of vacuum - and this is BMW's statement as you can see.

You need to provide clean measured source of air to the crankcase while using the PCV. This can be easily done through the vacuum F connector in the intake boot with a T connected to the dipstick previously plugged while a check (one way) valve is installed to prevent air/pressure from the crankcase going up to the intake.

[docnabimmer]

Originally Posted by Xelo

I must revive this thread upon new findings regarding the amount of vacuum the M54 pulls after this modification.

In latest SIB 110308 BMW states the amount of pressure/vacuum inside the M54 crankcase must be ~16 mBar (that is 0,48inHg). As measured while using the FRAM FV345 PCV valve, the vacuum is 12-15 inHg (or +500mBar). That is over 30x the limit the engine was designed for, this is insane!

And this amount of vacuum is at idle ! Please imagine what letting off throttle/decelerating at 3-4-5K RPMs will do to the level of vacuum
This will no doubtly damage seals/orings inside and deprive the oil pump of oil, lowering oil pressure for brief moments on decelerations.

I have not met another engine in the world where upon opening the oil cap that much vacuum is present. This is wrong and must be addressed as this modification transforms a Closed Crankcase Ventilation system into a Positive Crankcase Ventilation system, but without all the elements needed for such a PCV system to work.

Inside classic PCV systems/engines, there is a continuous air circulation inside the crankcase because there are 2 holes letting the crankcase breath: first one lets the blowby exit being sucked by the intake through the PCV and the 2nd one lets fresh filtered air inside the crankcase in order to: 1) limit the amount of vacuum being built 2) properly vent all areas of crankcase in a wide range of engine RPMs
Usually this 2nd hole sucks air from the intake downstream (after) of filter/MAF/MAP but before (upstream) throttle - where the vacuum is low when throttle is closed.

By removing the CCV (OK), plugging the dipstick drain hole (not OK) and rerouting the crankcase blowby venting directly into the intake (OK) you have designed an incomplete PCV system. One has to allow the block/crankcase to be vented with fresh air from a clean source otherwise it would be like sucking air from a plastic bottle: something/somewhere will colapse and those will be either your VCG or rear main seal.

By venting the block through a 2nd hole you are punching a hole in that plastic bottle you are sucking air out of: while the sucking is still there, the bottle will not collapse anymore as some small venting/air is let in keeping it vented.

If this worked for some of you it does not mean is a right thing, the engine was not designed for this amount of vacuum - and this is BMW's statement as you can see.

You need to provide clean measured source of air to the crankcase while using the PCV. This can be easily done through the vacuum F connector in the intake boot with a T connected to the dipstick previously plugged while a check (one way) valve is installed to prevent air/pressure from the crankcase going up to the intake.

Thank you Xelo for your input.
I know you have doubts about this MOD since 2019 (post #253,) did you actually do the MOD and the corrections you suggested, what were the results if you dont mind sharing?
and would you change to the PCV1124DL before measuring the vacuum. We dont use the FRAM 345.
And if indeed there is a a reduction in vacuum, would connecting the F connector to one of the rear unused ports at the back of the intake manifold be as effective?(this is the port that is used by the O2 Pilot Mod)
thank you

[2004325ciLover]

I'm 10K miles in.

Oil consumption went from a quart every 800ish miles to a quart every 3500ish miles.

I have 180K miles on my engine. No major leaks. RMS and oil pan has tiny amount of sweat, but has since I've owned the car at 134K miles.

Doc, do you ever throw an SES for high STFTs?

Here's what is occurring for me ever since I performed the mod:

https://youtu.be/LBC6gBnxTRY

[docnabimmer]

Originally Posted by 2004325ciLover

I'm 10K miles in.

Oil consumption went from a quart every 800ish miles to a quart every 3500ish miles.

I have 180K miles on my engine. No major leaks. RMS and oil pan has tiny amount of sweat, but has since I've owned the car at 134K miles.

Doc, do you ever throw an SES for high STFTs?

Here's what is occurring for me ever since I performed the mod:

https://youtu.be/LBC6gBnxTRY

I had the EXACT SES light with High LTFT like yours, traced it to a loose connection between pcv hose to rear intake port. I tightened that up and have never had an SES light since. Monitoring LTFT after that shows my readings hovering around the 5-8 not going over 10 and triggering a SES.
just keep in mind that will all this I noticed a small oil leak that i had thought was from the OIL Level sensor- it wasnt, it was from a split RUBBER Cover to my OIL DIPSTICK TUBE.
5k into the MOD and I chickened out thinking it was my RMS or OIL PAN GASKET.
Went back to our conventional CCV factory set up with 5-30 Supertech FS.(yes-thats right)

So far 1/2 quart low .2000 miles in.SWitch to Rotella next.

[Fifty150hs]

Originally Posted by docnabimmer

I had the EXACT SES light with High LTFT like yours, traced it to a loose connection between pcv hose to rear intake port. I tightened that up and have never had an SES light since. Monitoring LTFT after that shows my readings hovering around the 5-8 not going over 10 and triggering a SES.
just keep in mind that will all this I noticed a small oil leak that i had thought was from the OIL Level sensor- it wasnt, it was from a split RUBBER Cover to my OIL DIPSTICK TUBE.
5k into the MOD and I chickened out thinking it was my RMS or OIL PAN GASKET.
Went back to our conventional CCV factory set up with 5-30 Supertech FS.(yes-thats right)

So far 1/2 quart low .2000 miles in.SWitch to Rotella next.

I wouldn't expect much by changing oils. Before I did the mod I tried various weights up to 10w60 and had no appreciable effect on consumption.

[docnabimmer]

Originally Posted by Fifty150hs

I wouldn't expect much by changing oils. Before I did the mod I tried various weights up to 10w60 and had no appreciable effect on consumption.

yep , im back there again - i still have my set up though and ive become adept at taking off and installing the conventional CCV in our cars that i dont mind it at all now ...current consumption is "acceptable" to me but i would like it close to the negligible Bavarian moD result like i had...

[ramp]

In all my years driving BMWs. This has been the most significant post I have adopted. My old e39 is currently being driven by my son. I believe 200K miles and very little oil use on this variant.

[Xelo]

Originally Posted by docnabimmer

Thank you Xelo for your input.
I know you have doubts about this MOD since 2019 (post #253,) did you actually do the MOD and the corrections you suggested, what were the results if you dont mind sharing?
and would you change to the PCV1124DL before measuring the vacuum. We dont use the FRAM 345.
And if indeed there is a a reduction in vacuum, would connecting the F connector to one of the rear unused ports at the back of the intake manifold be as effective?(this is the port that is used by the O2 Pilot Mod)
thank you

No, PCV1124DL is too restrictive for the volume of airflow needed. You need to keep *at least* the diameter of the OE hoses for the blowby to be properly evacuated. Fram PCV meets the exact size of OE hoses (16mm) and is already used in engines with a displacement much larger than M54, so there are no worries regarding flow of gasses.


Secondly, you need to vent the crankcase, not the intake. Connecting F to back of intake (02pilot port) is senseless, that will make the vacuum past TB suck air after MAF, increasing the amount measured by MAF and increasing mixture adaptations.
F port is already connected to the intake by the hoses merging to brake booster.


Third, I indeed had this CCV-to-PCV modification done, as presented in previously posts. Kept OE hose size all over, exiting VC with 19mm to catch can, then 16mm from CC to Fram PCV and continuing with 16mm to vacuum distributor above intake keeping all original ports for proper distribution of vacuum to all cylinders. Kept original hose plugs for look and proper sealing.




Capped vaccum port at the back of the intake.



Then connected the F port to the oil dipstick old CCV port, but installed a one way valve between (not letting the oil being sucked into intake if something backfires; crankcase sucks filtered and *already measured* air from the intake elbow).


Car runs great, fuel trims at max +/- 2-3%, baffled catch can does its job, not able to make a definitive oil consumption assesment as not moved much on highways with these COVID restrictions.




Pics:
https://postimg.cc/PL2Ktg3x
https://postimg.cc/d7v6wrqF
https://postimg.cc/JGDPqRTf
https://postimg.cc/bs7LV4Ws
https://postimg.cc/sBVFqvSj
https://postimg.cc/NK8qd1KC
https://postimg.cc/CRppCvxf
https://postimg.cc/GBWSWqbw

[trhaverstock]

I did this mod about a year ago (exactly following the original post) and then recently started throwing P0171 and P0174 codes and she was running like crap. I built my own DIY smoke tester and fired her up and quickly found I had a good leak there I should have had a cap per this original instruction:

"After that you have to plug the port on the opposite end of the air distribution piece, I found a red plastic cap that fit in very tight."

I didn't have anything I could find that would fit great so I had cobbled something together and it had come loose causing this issue.

Well, long story short I found that the following product fit very well for this application: Dorman rubber expansion plug #02608. I bought it at O'Reilly an it was around $4.00. You should be able to search this and find it about anywhere that sells auto parts. There is a small nut on there you tighten. I am highly confident this will never come loose and I am impressed how smooth things are running now compared to what I was used to.

Good luck all!

[Bmwe5320023.0]

Originally Posted by Xelo

I must revive this thread upon new findings regarding the amount of vacuum the M54 pulls after this modification.

In latest SIB 110308 BMW states the amount of pressure/vacuum inside the M54 crankcase must be ~16 mBar (that is 0,48inHg). As measured while using the FRAM FV345 PCV valve, the vacuum is 12-15 inHg (or +500mBar). That is over 30x the limit the engine was designed for, this is insane!

And this amount of vacuum is at idle ! Please imagine what letting off throttle/decelerating at 3-4-5K RPMs will do to the level of vacuum
This will no doubtly damage seals/orings inside and deprive the oil pump of oil, lowering oil pressure for brief moments on decelerations.

I have not met another engine in the world where upon opening the oil cap that much vacuum is present. This is wrong and must be addressed as this modification transforms a Closed Crankcase Ventilation system into a Positive Crankcase Ventilation system, but without all the elements needed for such a PCV system to work.

Inside classic PCV systems/engines, there is a continuous air circulation inside the crankcase because there are 2 holes letting the crankcase breath: first one lets the blowby exit being sucked by the intake through the PCV and the 2nd one lets fresh filtered air inside the crankcase in order to: 1) limit the amount of vacuum being built 2) properly vent all areas of crankcase in a wide range of engine RPMs
Usually this 2nd hole sucks air from the intake downstream (after) of filter/MAF/MAP but before (upstream) throttle - where the vacuum is low when throttle is closed.

By removing the CCV (OK), plugging the dipstick drain hole (not OK) and rerouting the crankcase blowby venting directly into the intake (OK) you have designed an incomplete PCV system. One has to allow the block/crankcase to be vented with fresh air from a clean source otherwise it would be like sucking air from a plastic bottle: something/somewhere will colapse and those will be either your VCG or rear main seal.

By venting the block through a 2nd hole you are punching a hole in that plastic bottle you are sucking air out of: while the sucking is still there, the bottle will not collapse anymore as some small venting/air is let in keeping it vented.

If this worked for some of you it does not mean is a right thing, the engine was not designed for this amount of vacuum - and this is BMW's statement as you can see.

You need to provide clean measured source of air to the crankcase while using the PCV. This can be easily done through the vacuum F connector in the intake boot with a T connected to the dipstick previously plugged while a check (one way) valve is installed to prevent air/pressure from the crankcase going up to the intake.

Here's my test. So I just measured directly at the hose that goes into the distribution box that's connected to the manifold.
So manifold is pulling 16-17 inHG instead of 0.48 inHG?
Does the original CCV system then blocks the vacuum at the diaphragm and doesn't let it pull so much from valve cover?
I guess to confirm all we need to do is have someone with the stock CCV system measure the vacuum?
Which is probably going to be like bmw says 0.48inHG?
So on this case it's true, the vacuum with this mod is 30 times stronger.
Now how much vacuum is safe for the seals?
Just for fun I sucked on that gauge as hard as I could, and it showed 23 inHG lol! So it relative terms that I can relate to, it's not that much suction...



But it's probably enough to stop the oil consumption...
Here's CN90's picture, numbers are just examples.
BTW I wonder if CN90 is still around with thus mod?

Fifty150hs I think your mode is a bit different because you installed a catch can??