Vanos adjuster unit issue - cover

[deansbimmer]

Originally Posted by toolshed

BMW designed those plastic caps to dry off and go off at 100k miles and thus could damage engine. Isn't it seem strange?
Why didn't they design better ways to fix springs at their places instead of weak plastic?

BMW designed lots of plastic parts in the car that can break at high mileage, look at BMW's infamous plastic cooling systems. Lets make everything out of metal?

[Iyzmi]

Originally Posted by toolshed

BMW designed those plastic caps to dry off and go off at 100k miles and thus could damage engine. Isn't it seem strange?
Why didn't they design better ways to fix springs at their places instead of weak plastic?

It's actually a very rare issue as far as I know. This is the second thread I've seen mentioning it in my 4 years on the forum. The other was from a guy in Poland, and that thread got very little attention. I'm tempted to believe it's even rarer than rod bearing failure, perhaps Dean can confirm? By the way - my car had nowhere near 100k miles on it when this happened. I was at 39,700 or so.

Attached is another pic where you can see the loose spring. I originally tried to patch the hole in the valve cover with JB Weld and run without the cap. I drove very lightly for a couple months to see if there would be any issues and everything was fine until I eventually took the car up to redline, then it started leaking oil again. There should be no debate here - the caps are absolutely necessary!

I strongly advise you not to take chances with this and get the VANOS unit(s) replaced. I lucked out in that no damage was done by the metal coming off the valve/timing chain covers going through the oil. I was very paranoid about long term effects after seeing what came out of the oil filter. My biggest concern was that the metal would damage the rod bearings and destroy the oil pump, but luckily the oil filter caught it all. And who knows what sort of damage the plastic shards could've done had they gotten jammed up in the wrong place. This issue was an absolute nightmare for me, especially because it occurred immediately after I purchased my car.

[Iyzmi]

Originally Posted by toolshed

On this picture spring is on it's place. What could scratch your cylinder head and valve cover that much? A gearwheel?

It's in place because the engine isn't running. I was able to move it around with my finger with very little effort. When the engine is running, particularly at high RPM, the spring can swing out and make contact with whatever is in it's path (valve cover and timing chain cover). I can't think of any other explanation for the damage, there is no way the gear can move and make contact with those parts.

EDIT: Since you deleted that post I assume you figured that out.

[toolshed]

Originally Posted by SkinnedKnuckles

Hi deansbimmer,
The washer and central screw definitely cover a few mm of the spring end, and it appears that this would be enough to keep it in place. The cover is relatively weak, as you know, and it appears that it is not actually pressing on the spring at all. Maybe it helps a bit, but difficult to say imo.

I found a document with some good cutaway schematics and description of the vanos adjuster units, which help a lot (you've probably seen them, I will post when back at the PC). It says that the spring is used for "coordinating the adjustment time between the advance and retard adjustment." Sounds like it acts as a sort of dampener between the two opposite motions of the vanos (advance one way, retard the other).
Dealer tech mentioned that it sets a home or central or neutral position, but it seems there is a separate locking pin for that, that seems to engage when there is no oil pressure.
Seeing those schematics makes me think that the only way the covers/caps could have rotated might be due to some shock loading and inertia effects i.e. The rotor being activated and hitting hard against the housing, perhaps after the oil drains/leaks out of the units, and thus causing the covers to shift very slightly due to their inertia. This could be part of that cold start rattle issue that I've read so much about...?
I'll post those schematics soon, they are extremely helpful in understanding how these adjusters work, and I couldn't find much detail at all via Google or the dealer, so really glad I stumbled across them!

Maybe you mean this doc
https://drive.google.com/file/d/0B_W...hGN2FBS0k/view

[aptwave]

Originally Posted by deansbimmer

What is your claim based off of? Extensive first hand experience??



You don't have to feel certain, we will tell you for sure that the spring will EVENTUALLY come off.



Good for him? He took a major risk and went against the BMW design and everything we know about the system (and common sense). Who's to say it wasn't going to fall apart after a few more days?



This is incorrect, again. There are clips on the back of the cap that snap into the vanos housing. It takes considerable skill to remove an intact cover without braking it. These are not intended to be disassembled and BMW specifically states this. Are inspecting broken units and online pdf's your only vanos experience?



In 100% of cases, springs coming off the hub ARE due to lost caps. The spring isn't forcing itself against the cover but it needs the cover to retain it from walking off the spring posts. If you set a vibrating shoulder massager on a table, it will walk all over the place. It is basically the same principle here. No significant force, but movement none the less.




You probably didn't know what you were looking at and missed this detail in his photo, but there are pictures just a couple posts above of Iyzmi
showing his vanos with the spring loose (no tension). He also said it ran fine. I will also confirm the engine will run without the spring, but was noisy in my experience (and it also ended up breaking the vanos internals seen in my pic above). I also explained the spring's function above. In case you didn't understand the gist, it wouldn't inhibit engine function if it were missing.

Why is this even a discussion? BMW designed it that way for a reason which everyone here has confirmed was valid. If you are hell bent on risking damage or destruction of your engine by leaving the covers off, that's your decision but you're arguing uphill on this. Nobody is going to stop you but you're trying to convince yourself it's going to be OK when its actually going to be a major risk that most likely won't end well.

Seems like we misunderstood each other and were talking about different things.

I mean that cap will not save spring to go in this direction and remove it off from VANOS unit:




But you were talking about issue when spring can expand like this, if there's no caps, right?

[Bartledoo]

Nope.

[SkinnedKnuckles]

Originally Posted by toolshed

Maybe you mean this doc
https://drive.google.com/file/d/0B_W...hGN2FBS0k/view

Yes! That's the document! Page 50-52 shows and describes the vanos unit.
This was hard to find, I stumbled on it via another thread talking about cold start rattles and discussing oil galleries/pathways.
Excellent reading and the only place I've seen cutaway images and descriptions of how this version of the Vanos works.

The cap does indeed clip on around its edge via about 6 narrow tabs - I didn't know this when inspecting the one I removed, and broke it when prising off. The bakelite(?) gets brittle and fragile with all the heat cycles by the look of it..

Although it's weak/thin/light, I can see how it would help to keep the spring in place if it wanted to walk out of its outer retaining pins.

It was great to see the cutaway pics as before I couldn't work out how the oil caused relative rotation of the two parts! Now it is clear!

That little locking pin is interesting too - I assume there is a little oil gallery that allows the oil pressure to act on the lip of that pin and push against its little spring force, to retract it (disengage) when the engine fires up. Interesting.

Deansbimmer, do you think that oil draining from the unit might allow a rattle on cold startup? By this I mean that if one side is being fed oil but the other is "dry", that the rotor may slap against the stator due to lack of resistance?
I read another thread about a guy (M3PO?) solving cold start rattle by replacing a vanos unit, so perhaps something to do with the spring/pin/leaking/sealing..?

[SkinnedKnuckles]

Originally Posted by gfisher99

Does your noise sound like mine? Start at the 25 second mark, sound is most audible around 27 seconds. It's like gear meshing or timing chain rubbing on the guide noise that comes and goes (not in rhythm) but is always there. I have had an indy BMW specialist and a BMW dealer both listen to it and they have nothing to say. I worry because I've never heard another S65 sound like mine.

I have put a stethoscope all around the engine and the sound is most notable when putting the probe on the cross-hatch patterned area on the front of the driver-side cylinder head.

My next step is to have deansbimmer take a listen when I have it in for rod bearings at some point.

Hi gfisher, no my noise is less metallic and more "faint" that yours. It's very difficult to hear at idle, but appears clearly under load and higher rpm. Could even be some type of air/exhaust leak... not sure, but hopefully will get to the bottom of it soon. The vanos was perhaps a side issue, that I noticed through the oil filler hole (could see the vanos cap bulging out when looking in there).

I would encourage everyone to look in their oil filler hole, and rotate the engine by hand, observing the black caps on the vanos unit/s that you can see on that RHS, to make sure they are properly seated and that nothing looks suspicious!

Here's what I saw with mine (notice the cap deformed/bulging):

Note the damage/peeling of the coating on the valve cover! Luckily I had an old picture from 2 years ago, that I took because I noticed this back then. The second picture shows this peeling from 2 years ago, with that coating damage there back then... So I assume it is not related. (note i wiped i with my finger hence the smudge marks).

Question: Does this engine always stop in the same position? Currently, it stopped essentially at TDC. If it always does this, then I could tell that the vanos cap issue has occurred sometime in the past 2 years, and definitely since I have owned the car. So it could not be from someone else messing around in there at all, and must be the result of some operational/mechanical effect while running.
It looks like it might be in the same position in the 2 pics, as there is a very slight indent/mark on the cap that coincides with the alignment tabs that are on the inside surface of the cap (clearly visible in the first pic (the small light spot), and maybe noticeable in the second (although i hand't wiped the cover and hard to tell exactly)).

Thoughts?

[bigjae1976]

Can you get a used set of gears from a motor with a spun bearing and just swap the covers?

[SkinnedKnuckles]

BTW, here are the key pages from that document that describes and illustrates the Vanos in these cars. Very different than the previous/other helical gear arrangement vanos system!

[SkinnedKnuckles]

Originally Posted by bigjae1976

Can you get a used set of gears from a motor with a spun bearing and just swap the covers?

Possibly, yes, but I really do not know why the covers spun, and am leaning towards a new complete adjustment unit to be sure... expensive guessing game I know!
I could also take the unit apart (although bmw advises clearly not to!) to ensure everything "looks ok", but I guess I would never be sure about proper oil sealing on all those surfaces in there! It might look fine but there could be some reason that they spun that I cannot deduce just by inspecting them..?

BreakMyWallet!

The only unusual thing i have noticed was a rattle upon start-up once immediately after the previous oil change. Just once, just after the change, never again. This oil change was after the other weird faint ticky/clacky sound appeared, so I knew that i didn't do something during the change to cause the new sound to surface. The rattle happened only for a couple of seconds, i assume until oil pressure built up. The interesting thing is that I have done several oil changes on this car and never heard this before upon restarting. Never. It was very rattly, I presumed timing chain slapping about until the tensioner saw pressure...

I am starting to think that that rattle was somehow the cause of the spun vanos caps? if those units/gears were oscillating hard (or the internal rotors perhaps slapping against the "stators", this may have caused the caps to spin due to their inertial response..? Long shot I know, but I cannot think of another logical explanation or any other forces acting on those caps to make them spin and ride up on their alignment tabs like that!

[Shredicus]

Well this is something I've seen pop up on the forums a few times over the years. Wonder if an aftermarket solution made of Delrin or Nylon would be a possibility?

[toolshed]

Originally Posted by Iyzmi

It's actually a very rare issue as far as I know. This is the second thread I've seen mentioning it in my 4 years on the forum. The other was from a guy in Poland, and that thread got very little attention. I'm tempted to believe it's even rarer than rod bearing failure, perhaps Dean can confirm?

I cannot say that rod bearing failure is rare, you can find special thread on this forum with endless list.

[toolshed]

Originally Posted by Shredicus

Well this is something I've seen pop up on the forums a few times over the years. Wonder if an aftermarket solution made of Delrin or Nylon would be a possibility?

Trying to find out a possibility of making copies of these covers on a 3d plastic printer machine

[Iyzmi]

Originally Posted by toolshed

I cannot say that rod bearing failure is rare, you can find special thread on this forum with endless list.

You can also find that most people agree that the failure rate is ~1%. Even if it's 5x more than that estimate, it's still very rare.

[deansbimmer]

Originally Posted by toolshed

Trying to find out a possibility of making copies of these covers on a 3d plastic printer machine

The OEM material is already the most robust for the application. 99% of these covers are working just fine in these engines, often well past 100k miles. You're not going to find an oil impervious 3D printable material that is going to beat that. And would you really want to risk testing one? When they fall apart they will clog the pickups and impede oiling.

[toolshed]

Originally Posted by deansbimmer

The OEM material is already the most robust for the application. 99% of these covers are working just fine in these engines, often well past 100k miles. You're not going to find an oil impervious 3D printable material that is going to beat that. And would you really want to risk testing one? When they fall apart they will clog the pickups and impede oiling.

I've just find out that 3d copies are not fit for engine because of weak mechanical and temperature properties.
Only special plastic molding can work fine.

[SkinnedKnuckles]

Originally Posted by deansbimmer

The OEM material is already the most robust for the application. 99% of these covers are working just fine in these engines, often well past 100k miles. You're not going to find an oil impervious 3D printable material that is going to beat that. And would you really want to risk testing one? When they fall apart they will clog the pickups and impede oiling.

Hi deansbimmer, thanks again for all of your comments and advice, and thanks to others also, much appreciated!
I have ordered another unit for the LHS inlet camshaft; I figure it's safest just to replace despite by knowing what caused the spun caps.

I was thinking about options for an alternative, not that I'm trying to find one now, just a thought - perhaps a modified washer for that central bolt could do it..? That washer could be replaced with a larger disc-like design that extends out over the spring, with appropriate clearance of course. Could be machined with slots or holes, but would effectively act as a retaining disc/cover for the spring...? It would then be sturdy, heat resistant etc., and not be able to come off at all!
Perhaps even a thin disc added over the washer, perhaps a 1mm thick disc (perforated/slotted perhaps), as there is a decent amount of thread engagement on that central screw so 1mm less is unlikely to hurt..?

Just some random thoughts for a Saturday morning!

I'm still perplexed as to why my covers spun though!! On both inlet adjusters!
I still think it must be some kind of inertial response to rapid jolting/oscillation of the adjuster somehow... Strange... Sure hope it does't happen to the new ones I put in - Big $$!!

Cheers

[SkinnedKnuckles]

Oh and I also discovered that my idler pulley on the aircon side is on the way out (bearing). Not bad bad but getting there. This could have been the cause of my faint ticking sound, I sure hope so. In any case, I'm glad I spotted the cam adjuster cap issue, as I'd hate to be pulling the sump etc off if those caps came off and got munched up in there

[toolshed]

already make 2000 km without all four caps

[Iyzmi]

Originally Posted by toolshed

already make 2000 km without all four caps

Not as impressive as you seem to think. I too thought the cap may not be very important. I initially left the VANOS cap off when I discovered this issue and simply patched the hole in my valve cover with JB weld to see if it would come back (pic attached). 3 months and about 5,000km later - the hole in the valve cover was back. The harder you drive the car, the quicker shit will hit the fan. Likely nothing will happen if you drive the car lightly though. Not sure why you choose to ignore the photographic evidence I have posted and the advice of one of this forum's most trusted technicians.

[deansbimmer]

Originally Posted by Iyzmi

Not sure why you choose to ignore the photographic evidence I have posted and the advice of one of this forum's most trusted technicians.

Because Russia. The land of willful suffering and masochism. And apparently where its preferred to tempt the German S65 lottery gods.

*this was written with humor in mind, don't come at me*