Does passing the PCV vacuum test mean my OSV is fine? 740i with M60 engine

[LysanderSpooner]

In my ongoing attempts to pass California smog (see here) one of the things I replaced was the PCV at the back of the manifold. Every time I've pulled the PCV there has been a lot of oil inside the manifold. A few days ago I pulled the oil pan and ran about 3' of weed whacker line up through the feed tube from the OSV, and I could swear the car runs better now just from doing that.

Today I did Timm's vacuum test and it passed with flying colors, pulling about 5.5 inches of oil through the tube. Now I'm curious to know if that's a sign that my OSV is doing the job. I suppose I could pull the PCV again and see if there is any oil present. I would sure like to know before I go back for another smog check.

[LysanderSpooner]

Well I pretty much answered my own question by pulling spark plugs in cylinders 3 & 4, and #4 is noticeably darker from the oil that is being washed down that cylinder:

IMG_7535.jpg

I understand that this issue was rectified on the MB62 with the addition of the outlet tube the runs forward inside the intake manifold to allow the oil vapors to disperse to all cylinders.

So now another question... has anyone ever tried adapting the external OSV and PCV from an X5 to the MB60?:

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[Timm]

The test shows that the PCV is fine - but my best guess is that the OSV is not fully working as the diameter has decreased with a buildup of oil varnish, and they don't like that. Cylinders 4 and 8 are often more coked, you can fit the M62 inlet manifold along with its mixing system, but it really isn't worth it. Although darker it doesn't stop the cylinders firing as usual.

[LysanderSpooner]

The test shows that the PCV is fine - but my best guess is that the OSV is not fully working as the diameter has decreased with a buildup of oil varnish, and they don't like that.

So that's how they go bad, with varnish buildup inside?
And this explains the excess oil being found in the manifold, because it cannot drain down into the pan?
And would it be correct to assume that just because I was able to pass the weed whacker line through it from below that I didn't necessarily clear the blockage, leaving the problem uncured?

Cylinders 4 and 8 are often more coked, you can fit the M62 inlet manifold along with its mixing system, but it really isn't worth it. Although darker it doesn't stop the cylinders firing as usual.

So plugs 4 and 8 are always darker on the M60 even without PCV/OSV issues?

[Timm]

Yes, that's why the mixing system was introduced on the M62, and nothing to worry about, they all show the same discolouration. The OSV is a cyclone, any debris within it inhibits the cyclonic action.

[LysanderSpooner]

Yes, that's why the mixing system was introduced on the M62, and nothing to worry about, they all show the same discolouration. The OSV is a cyclone, any debris within it inhibits the cyclonic action.

OK, so assuming a good PCV, the only way to know if the OSV is working is the absence of oil in the manifold?

[Timm]

You will always get a little oil in the manifold - the cyclonic system is not perfect - as long as you are not puffing out clouds of smoke you are OK. If you ARE puffing out smoke and have replaced the PCV then further investigation of the OSV is in order!

[LysanderSpooner]

You will always get a little oil in the manifold - the cyclonic system is not perfect - as long as you are not puffing out clouds of smoke you are OK. If you ARE puffing out smoke and have replaced the PCV then further investigation of the OSV is in order!

I just purchased a new OSV/cyclone valve and the necessary gaskets. From what I've read I think it's possible to wiggle the old one out and the new one in after removing the upper timing cover and perhaps the sprocket bolts to move the sprocket and chain out of the way. I haven't found any definitive info on this for the M60. Lots of talk about doing it on the M62, typically when the chain guides are also being done.