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I think we all agree that it could have been designed differently to have either better filtration or even better a completely independent oil supply to have the oil ONLY be to operate the hydraulics and not be shared for lubrication in a really dirty combustion engine. Lots of trade offs, this one was the most compact and direct though.
Do not understand why, but manufacturers are really stretching the oil change intervals at cost of basic engine problems. I am not a petroleum engineer, but even as a kid, changed oil in my lawn mower when it got dark. My mower is now 34years old and still working.....although in honesty, not used much now.

On all my vehicles, was 3k oil change, but now ~5k with Mobile one only. BMW now trying to strech to 15K! Even GM going with upwards of 10K/miles. Not good for all the little seals, and passages, esspeically on a car not driven a LOT of miles in a year. Even my 2013 smart fortwo recommends 10k/mile intervals! On S85 will have to plan, but it does have SUPER capacity. It will be 5k max or 1yr. Clean happy "honey colored" oil with happy seals, o-rings, etc.

Mr. P
 

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E60 M5 and building engines
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I think the bigger issue is that degraded oil stays in the hydraulic circuit of the VANOS and cycles back and forth because there is minimal fluid exchange, it just cycles back and forth through the double acting cylinder. This slurry degrades the orings on the solenoids and you get bypass. When I removed my solenoids I noticed how dark the oil was and I had just changed the oil and run the engine for a bit. Hence my point of it should have been a stand alone isolated circuit. There is no way for the oil there to be exchanged when you do an oil change.
Hello gmtegear,

Do not believe only cycles "back and forth" through the H.P. VANOS system.

Cycle is H.P. feed from pump, release at each VANOS unit and return to sump. Volume of H.P. oil very low, but directional from pump to relief.

Mr. P
 

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E60 M5 and building engines
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Hello gmtegear,

Do not believe only cycles "back and forth" through the H.P. VANOS system.

Cycle is H.P. feed from pump, release at each VANOS unit and return to sump. Volume of H.P. oil very low, but directional from pump to relief.

Mr. P
Adding: Only exception is H.P. VANOS accumulator. Have not noticed return to sump on this part of the hydraulic VANOS system. It maybe something to consider when changing oil? Or major service.

Output of H.P. pump so low BMW added the accumulator for faster and more consistent response.
 

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Do not understand why, but manufacturers are really stretching the oil change intervals at cost of basic engine problems.
I am not a petroleum engineer, but even as a kid, changed oil in my lawn mower when it got dark. My mower is now 34years old and still working.....although in honesty, not used much now.

On all my vehicles, was 3k oil change, but now ~5k with Mobile one only. BMW now trying to strech to 15K! Even GM going with upwards of 10K/miles. Not good for all the little seals, and passages, esspeically on a car not driven a LOT of miles in a year. Even my 2013 smart fortwo recommends 10k/mile intervals! On S85 will have to plan, but it does have SUPER capacity. It will be 5k max or 1yr. Clean happy "honey colored" oil with happy seals, o-rings, etc.

Mr. P
Elementary Watson
If cars lasted 34 years car makers would go broke.
Decades ago the strategy of built in obsolescence started being employed in order to motivate customers to buy new cars more often.

However the many Lawyers looking for work found ways to interpret built in obsolescence as design flaws.

Extending oil change intervals is a safe way to turn cars into smoking wrecks after warranty expires With little risk of class action law suits.
Even my wife with no interest in cars has seen the benefits of my maintenance methods.
I have a standing order to only buy new, since too many used cars followed manufacturers oil change intervals.
 

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Dyno oil has been used for 5k miles forever... And engines lasted forever too. Modern oil lasts longer because well... It's better. Doesn't thin out as much, wider visc range, better detergents, etc. Costs more too. Now I'm not pushing 15k but I'm very comfortable doing 10k OCI.

For us who care there's also an environment cost with short OCI.
 

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Do not believe only cycles "back and forth" through the H.P. VANOS system.

Cycle is H.P. feed from pump, release at each VANOS unit and return to sump. Volume of H.P. oil very low, but directional from pump to relief.
The diagram I posted is a bit odd, the left side diagram only has ONE return to “ground”, which I’m presuming to be a small orfice in the vanos actuator assembly that just dribbles the oil to the cylinder head, I don’t see any need to have a dedicated line back to the sump since this is not an isolated circuit design. The right side shows 2 grounds. It’s not clear how much flow there really is in operation, but given the bleed cycle is 18 minutes and the total volume of fluid in the circuit is small, it l’d venture to say the flow is low.

In actual operation the solenoids are serving as proportional valves, so hydraulic pressure is being proportioned to both sides of the cylinder to maintain a certain stroke to advance or retard the gear powering the cam. What I observed, as many others have noted as well is when the solenoids are removed, the oil is quite dirty. It makes sense if you look at the orientation of solenoid. There is a low point where the fluid (oil) pools. That’s exactly where dirt and debris in the system will accumulate, just like in the corners and crevices of the oil pan. If this circuit was a closed loop system like the SMG hydraulic circuit, then we’d (theoretically) have less to worry about dirt, as it would be isolated from
the engine oil, which is for lubrication and cooling and contains a ton of dirt.

Also if the vanos system was designed as a high flow system with no standing areas for dirt to pool, the dirt would actually flow through the system and be constantly flushed and filtered by the main oil filter. This is exactly how automatic transmissions work.

I think we have vanos issues largely due to dirty oil being unable to be flushed out of the vanos circuit despite oil changes, this wears out the orings, and eventually/potentially the vanos actuator cylinder seals. This is just my theory.

Also if there were return lines then I think we could make it a closed loop system by doing some rerouting and machining, but this doesn’t seem to be a fatal flaw that warrants that.
 

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Dyno oil has been used for 5k miles forever... And engines lasted forever too. Modern oil lasts longer because well... It's better. Doesn't thin out as much, wider visc range, better detergents, etc. Costs more too. Now I'm not pushing 15k but I'm very comfortable doing 10k OCI.

For us who care there's also an environment cost with short OCI.
Agree. Synthetic oils are far more uniform in the molecule size which makes it last longer and stay within a range. Dino oils had a lot of random sizes molecules that on average form a certain viscosity but when the bigger ones break down the average plummets very quickly. Not all synethetic oils are the same also, it’s just like the term organic. The really high end ones can and have been proven to last a very long time. In Germany for example they are hyper eco conscious and often say 12-18 months and well over 10k miles, closer to 20k for OCI on some cars. Most cars also don’t have a 8k redline and require the lubrication properties ours do either. That said, I’m sure many US M5 owners are not also likely not as proactive on brake fluid, trans, and diff fluid flushes. Yes I know some of these are “lifetime” fill, but that begs the question “how long is a lifetime for any BMW let alone an M5?” German car owners tend to get that all serviced together in prep for TUV certification.
 

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Discussion Starter #371 (Edited)
Since you tribological thread hijackers have carjacked the efforts to revive my lovely 06 m5... there are really only a few tribological pinch points in an engine. Cam interface and tdc top ring are probably worst cases in the S85. Hot idle is probably worst case on cam interface. I will say in my professional life one can see oil shear out in first few hundred miles of durability tests. I'd suggest 5k interval on oil as cheap insurance....but that's just me.
 

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Hello desmo01,

Have to laugh! Did not intend to cause to much friction on your post.

Cheers!
Mr. P
 

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I think Jürgen's hammering is his way of telling you he wants wants more hefeweizen, oil color is like beer.
 

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Where are you reading this? Depending on context, it could just be degree of relative advance or retard from nominal/default. Or exactly as you said.
 

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Discussion Starter #377
For example in INPA data. The numbers would make sense for lobe centers...I'll have to look at my N54 stuff too, I'm sure it's the same datum for advance...
 

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Makes sense in a diag tool that they would be absolute values which i think is consistent with what you believe.
 
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