ard

FYI-

The document I linked is a kind of training manual/theory of operation/overview... the TIS is much more detailed.

But if the inspector is honest, he should feel very uncomfortable with his findings after getting a sense of the VANOS. If you want the TIS you can log onto the BMW website and access the TIS or a fee- perhaps print pages from that...

GL

A

100%Cocoa

Subscribing - I currently have a VANOS issue so I'm keen to hear the outcome......

Apeman

First, let me start by pointing out that I don’t really know anything about engines. My understanding of the VANOS unit is based purely on reading documentation available through various online forums such as this one.

Still, I would like to comment on some of the statements made in the previous posts. By and large, I agree with what has been said; I’m just trying to clarify some points where my understanding is lacking or slightly different. Let's call it a learning exercise on my behalf

I'm currently experiencing some VANOS related issues with my own car, so this is all very interesting to me. Please feel free to correct any misunderstandings or false assumptions

And now for the comments:

Quote:

Originally Posted by Inspectors_report (2) We have been advised that the Vanos system has to be set to a default position before fitment to the engine. This procedure involves applying compressed air to an oil hole in the Vanos unit and that this should position both the camshaft position actuators in their default position. The Vanos unit is then inserted into the camshafts and secured. If the Vanos system is functioning normally the engine will run as designed. Assuming that the the Vanos unit is in the default position, if for any reason the camshaft sensor or Vanos control valves malfunction, then the worst case scenario would be that the engine would run rough. (ie. its operating parameters have not been breached.)

Quote:

Originally Posted by ard As stated above, and as referenced in the BMW tech procedure attached, the camshaft timing is set based on the mechanical relationships between crankshaft and camshafts using special BMW locking pins and tools. This is done PRIOR to installing the VANOS.

Agree. To clarify, reading the TIS it appears the timing should also be verified (not set, unless there are issues) after installing the VANOS.

Quote:

Originally Posted by ard The procedure for setting the ‘uninstalled’ VANOS to the default position is found in BTW TIS (Technical Information System) documents. It does not involve using air.

Agree. However, a “special tool” is needed to electrically adjust the solenoid valves prior to manually pushing the VANOS actuators/splined shafts to their default position. Maybe this has caused some confusion?

Quote:

Originally Posted by ard In summary, the VANOS is set at a default position by hand. Not by using compressed air. (Note that the VANOS is actuated by ~100bar oil. Compressed air will have no effect.

I agree that the VANOS actuators are set by hand prior to installation. However, compressed air (2-8 bar) is used when checking the valve timing after installation of the VANOS. This seems to somehow control the VANOS actuators while rotating the camshafts by hand; I can’t really say I understand this procedure well enough. Again, this could have caused some confusion as air is indeed used but not for the purpose described in the Inspector’s report.

On a related note, the 100 bar oil pressure is used to quickly and precisely adjust the cam positions under normal operation. Less is probably needed if there are no specific requirements regarding speed and precision?

Quote:

Originally Posted by Inspectors_report (3) In the case with your vehicle, we believe that the Vanos exhaust camshaft position actuator was not in the default position and was in effect stuck in an advanced position. This would have allowed the engine to be started and the engine would have been running well whilst the exhaust camshaft position actuator was stuck in the advanced position. However, if the exhaust camshaft position actuator suddenly managed to free itself due to the action of oil pressure, heat (as the engine warmed up) and some normal engine harmonics together with the control components directing the camshaft actuator to move to the retarded position (as would be the case above idle speed), then this retardation could result in a greater exhaust valve overlap and corresponding higher exhaust valve lift than normal near Top Dead Centre. This greater than normal exhaust valve lift near Top Dead Centre in turn would be in conflict with the engine cylinder's pistons and they could touch resulting in bent valves.

Quote:

Originally Posted by ard The owner asserts that the damage to the engine was, in fact, caused by the CAMSHAFT being installed incorrectly. The owner believes that this was due to Motorline failing to properly check the CAMSHAFT position as REQUIRED in the BMWTIS procedure: In the BMWTIS the technician should check the camshaft position without any hydraulic connections- the potion is check mechanically, not pneumatically. This check is performed before the VANOS control was attached.

Just to be clear (again), the camshaft timing is manually set prior to installation of the VANOS. Camshaft timing is then verified after installation of the VANOS, using a combination of pneumatics and manual adjustments

I kind of see how the damage could theoretically have occurred as described in the report. While everyone agrees that a correctly installed VANOS unit cannot cause bent valves even if it fails completely, having a VANOS actuator stuck in the wrong position when attaching the VANOS unit could theoretically lead to exceeding the safe physical boundaries if the actuator decides to suddenly start working during engine operation.

I've tried to understand the installation of the VANOS as well as possible based on the TIS documentation and it seems to me that even if the damage happened as the report assumes, which I'm not even 100% sure is possible, the fault is with Motorline for failing to ensure correct VANOS installation.

Here's what I'm thinking; it would be nice if someone with first-hand experience of VANOS installation could chime in:

If only the exhaust side actuator was stuck, there should have been a visible and tangible difference between the actuators after having tried to push them in to the correct position prior to installation. One actuator not moving, the other moves nicely; the difference should be clear enough. Also, one will be protruding more than the other. While this could be slightly difficult to judge visually it shouldn’t be impossible.

If both actuators were stuck in the same position, giving a false impression of having reached the stop, an experienced mechanic should have noticed that as well and aborted mission. Using the “special tool” to control the solenoid valves, one should be able to pull the actuators out as well as to push them in. Also, rotation should be free at all points. If they’re stuck, they’re stuck; if they move I have a hard time seeing how they would move only a part of the way unless the solenoid valves suddenly failed or a major piece of metal filing got caught during this very procedure. I don't think there is any excuse for not being sufficiently thorough in this part of the installation.

Quote:

Originally Posted by Inspectors_report (4) We have been advised by the repairer that there are no checks that can be made on the Vanos unit itself to ascertain the position of the exhaust camshaft position actuator. It would also be timely to mention the oil and metallic swarf as other contributing factors to the Vanos malfunction. The Vanos unit is normally replaced as a complete assembly.

Quote:

Originally Posted by ard It is disturbing that the Inspector is again relying on ‘advise’ from the company who made this error in order to find fact in this matter. In the BMW TIS, there are, indeed, procedures to check for the proper position of the VANOS actuator. This is done mechanically by simple free rotation of the splined VANOS actuators.

It seems to me that the TIS says to push the actuators in rather than to rotate them, or am I missing something? The actuators will need to rotate freely in all positions anyway, right? While there may be no bulletproof way to check for the correct stop position of the actuator (the TIS doesn't really mention any visual alignment marks or similar, only says to press the actuators in to the stop), I think it should be fairly straightforward to exclude issues in the installation phase by being sufficiently thorough.

Again, regardless of whether Motorline failed to set the cam timing correctly or failed to notice issues in the VANOS installation phase, I feel the fault is clearly with Motorline. The TIS advises caution to ensure the correct position of the actuators prior to installing the VANOS, and if there was even the slightest doubt as to whether the stop position was correctly reached, the mechanics should not have installed the VANOS unit.

MYM05, if Motorline would have advised against installing your VANOS unit and you would have insisted, then they might have had a case. As it stands, it was ignorance on their behalf (in one form or another) that led to the valve issues and they should bear the full consequences.

ard

Thanks for taking the time to comment- and help a fellow M5er.

I had written my diatribe prior to reviewong the TISs on timing, vanos, timing chain replacement and head removal and reinstall. Once I read them it seems clearer that they cannot have a 'stuck vanos' if they followed the procedures involved.

As I read it, to remove and intstall the vanos your completely open the splined gears so there is no way that it was 'stuck'. If they failed to follow the procedure, and took a shortcut- then that is their problem.

My tactic would be to use BMWs published procedures to show that the only way the problem occurred must have been failing to follow that procedure. Once you get into 'discretionary' pricedures and 'what one mechanic says', it will be hard to win.

For example:

"we did the timing chain procedure, but didn't do the complete cylinder head procedure since it wasn't necessary"

"If you had done the full cyl head procedure, as BMW requires, whould you have fully tested the vanos and ensured that it was not jammed?"

"Well, we didn't think it was necessary since it was only the timing chain"

"apparent it was and BMW designed the procedure exactly for that reason"

Also, I assume he was charged based on BMW 'book time' that is based on following BMWs specific procedures...

Good luck Nelson

A

Apeman

MYM05, for what it's worth, I had a chat with the main M-mechanic at my local BMW dealership (those guys are really nice by the way). This was mainly to interpret the results of my VANOS tests (tested three times now) and to discuss further actions. While doing that, I also took the opportunity to ask him about the VANOS installation and the possibilities of screwing up the timing during that procedure. I didn't really have time to thoroughly explain the details of your case, but got some general insight into what could happen.

Some observations from this conversation:

1) Not all authorized mechanics let alone dealerships have ever changed an S62 VANOS unit. In addition to the fact that actual VANOS main unit failure is fairly rare, the cost of replacing it seems to make a lot of the owners
a) Try to find a less expensive indy
b) Just decide against fixing the VANOS and instead unload their cars as quickly as possible
c) Drive around with a malfunctioning VANOS unit, as long as it doesn't get excessively bad.

2) This may have been a misunderstanding on my behalf, but it seems that when changing the VANOS unit, the actuators/splined shafts are not always even changed but left in the engine while the VANOS housing is pulled out. If indeed this is possible, I imagine it could save a lot of time in installation since the timing wouldn't need to be reset? On the other hand it would mean there's even less experience in changing the VANOS units the "proper" way.

3) Not all mechanics thoroughly understand all the details of the S62 engine. This is completely my assumption, and I don't blame them. It takes a lot of hard work to gain more than an approximate understanding by reading manuals, and few people have first-hand experience of all aspects involved. When you encounter new challenges, you try to read up and follow documented procedures. This is probably true for most professions; I certainly cannot say I'm a subject matter expert in all the areas my customers may expect me to be.

4) The unfortunate truth is that mistakes do happen, especially with complicated procedures. There are many opportunities to screw up the timing during a VANOS installation, but none of them can really be blamed on anything but an oversight/error on behalf of the mechanic.

I probably made my position fairly clear with my previous post but here's an executive summary:

Don't put all your eggs in the cam timing error basket, the problem may have occured just as stated in the report. However, even in that case the blame would still be with Motorline since there are clear procedures for ensuring proper installation and an issue like the one they are suggesting is only possible due to negligence on their behalf.

phillym5

When you change just the vanos... you don't take the splines out. They disconnect via a 7mill and 10 mill wrench where the splines meet the vanos unit.

Apeman

You don't take the splines out of the vanos unit you mean? Or don't take the splines out of the camshafts and spline hubs? What I meant was that you would disconnect the splines from the vanos unit before completely pulling them out of the camshafts and spline hubs together with the vanos unit. Then reattach the splines by doing the same thing in reverse. Maybe that's not even possible, as I mentioned I might have misunderstood the mechanic but that's what it sounded like.

phillym5

Your right... I just checked. When you change the Vanos... the splines DO come out of the camshafts. Then you DO have to time that side of the car. So the valve cover has to come off.

Apeman

Yes, that's the official procedure according to the TIS, and the impression I (perhaps mistakenly) got from the mechanic was that this procedure is not necessarily always followed. From what he was saying, it sounded like the splines might be left inside the camshaft instead of removing the whole Vanos housing+spline "unit". That comment may not have been referring specifically to the S62 though, and was perhaps misinterpreted anyway.

My other point was that if the official procedure is not always followed, this would mean there are even fewer mechanics who have first-hand experience of the whole proper Vanos+valve timing procedure. Again, this is just speculation on my behalf.

Sorry to repeat myself, its just that I wasn't sure whether we were talking about the same thing or different things and my last comment was perhaps not that clearWas your original comment referring to that the splines wouldn't come out of the camshafts when changing the Vanos unit? That would support what I thought the mechanic was saying.

ard

I agree with this.... in regards to the OPs issue, it doesn't matter 'how many shops do it' or what the prevailing wisdom is... only what BMW recommends in the there workshop instructions.