Went for a drive, lost power and now car exhaust sounds like it has cams

[DJAM3]

I would think it depends if the solenoid valves close. If so, the oil can't drain back and the timing is locked right?

[sapote]

I would think it depends if the solenoid valves close. If so, the oil can't drain back and the timing is locked right?

Yes if the solenoids are all closed. But the DME doesn't know the vanos oil pressure is gone, and during driving DME actively controlling the cams and so some or all solenoids must had been opened then the oil escaped and pistons moved to retarded positions.

[karter16]

Yes if the solenoids are all closed. But the DME doesn't know the vanos oil pressure is gone, and during driving DME actively controlling the cams and so some or all solenoids must had been opened then the oil escaped and pistons moved to retarded positions.

I'm not so sure that the solenoids opening/closing would have any effect though? In normal operation the retarding side of the control pistons are always exposed to 100bar of oil pressure (as I've indicated in red)





As per BMW the advancing side of the control piston is a greater surface area, so that when it also is exposed to 100bar (via actuation of a solenoid) it advances the control piston (the pressure is the same on both sides of the control piston during advance).


When the solenoid for retarding (11 & 14) actuates it allows the oil on the advancing side of the piston to flow back through the filter to the low pressure oil system, thus reducing the pressure on the advancing side, meaning that the pressure on the retarding side now pushes the piston the other way to retard the camshaft.

If the camshaft is in an advanced position at the time of total oil pressure failure then there is no way the pressure on the retarding side of the control piston can be higher than on the advancing side as the retarding side of the control piston is always exposed to the supply pressure.

Therefore I don't believe it would matter what the solenoids are doing after pressure loss, there's no pressure force acting on the retarding side of the piston that is greater than the pressure force on the advancing side. The only options are:

1: Any combination of solenoids are open and therefore pressure on both sides of the piston is ~0.
2: All solenoids are closed and therefore pressure on advancing side is greater than pressure on retarding side.


Edit: Important point I missed noting in my post - the only difference between the S54 vanos and the S50 vanos hydraulic system (shown in above diagram) is that the S54 does not have #10 non-return valve. This is an important difference in the context of this discussion.

[jpy1980]

From the sounds of it, they might need to take off the oil pan and clean out any parts that fell out of the other VANOS. That means front subframe out and oil pan off, which typically takes about a day. Add another day for new VANOS install. They most likely have other work as well and could also be waiting on misc. parts.

Once again, our friend Slideways is correct! This is the message I got from the shop. Looks like the oil pan is coming out today and the car may be ready tomorrow. Sheeesh. :

Hu Julian,

Vanos is installed. What happened was the needle bearings and the cage all exploded and all the needle bearings are in the oil pan. I had my tech stick a magnet down and that’s what he was able to pull up. I had them pull the screen on the oil pan to see if any were accessible that way and all of them look like they are in the front sump which wouldn’t be accessible without dropping the pan to get all them out.

The picture on red cart is what it is supposed to look like to get an idea of all the needle bearings and the cage material in the pan. The picture on the blue blanket is your vanos. I don’t know how that would of happened but the bearing race came out which is weird because the snap ring is still in place. I would recommend we drop the oil pan and get everything out just to avoid future issues. There is a screen on the oil pump pickup that would prevent anything from being sucked up but recommend removing to prevent any future issues. Let me know your thoughts.

[eacmen]

Once again, our friend Slideways is correct! This is the message I got from the shop. Looks like the oil pan is coming out today and the car may be ready tomorrow. Sheeesh. :

Hu Julian,

Vanos is installed. What happened was the needle bearings and the cage all exploded and all the needle bearings are in the oil pan. I had my tech stick a magnet down and that's what he was able to pull up. I had them pull the screen on the oil pan to see if any were accessible that way and all of them look like they are in the front sump which wouldn't be accessible without dropping the pan to get all them out.

The picture on red cart is what it is supposed to look like to get an idea of all the needle bearings and the cage material in the pan. The picture on the blue blanket is your vanos. I don't know how that would of happened but the bearing race came out which is weird because the snap ring is still in place. I would recommend we drop the oil pan and get everything out just to avoid future issues. There is a screen on the oil pump pickup that would prevent anything from being sucked up but recommend removing to prevent any future issues. Let me know your thoughts.

I would advise that you make them check VANOS oil pressure after the work is done.

[bigjae46]

Geez...that shopped butchered the original job which is why the needle bearing failed. There is no way for the inner bearing race to come out like that with the clip and belleville spring installed.

The shop should also check the timing chain, oil pump chain and all of the plastic chain guides. There is one guide that is metal but has a plastic wear surface that gets old and brittle and could crack. That will cause all sorts of issues. There is absolutely a possibility that a small piece of a bearing or bearing cage can get through the witches hat in the oil pan or into the front pickup if the mesh is torn.

[inlinesix123]

HA! i am not the only one, the shop that installed my brand new full beisan unit messed up, they assembled it incorrectly which caused me 100+ hours of research and tinkering on my car only to find out that apparently Curious George himself worked on my car, that's the only explanation. Such a pain in the butt to diagnose as well, have to take everything apart.

This picture is an accurate representation, since my car is Phoenix Yellow as well.

[jpy1980]

HA! i am not the only one, the shop that installed my brand new full beisan unit messed up, they assembled it incorrectly which caused me 100+ hours of research and tinkering on my car only to find out that apparently Curious George himself worked on my car, that's the only explanation. Such a pain in the butt to diagnose as well, have to take everything apart.

This picture is an accurate representation, since my car is Phoenix Yellow as well.

Did you get it all sorted out?

[jpy1980]

Damn when I get the car back, I should take it to another shop to get it properly diagnosed. Not sure if I trust this shop anymore.

[sapote]

Therefore I don't believe it would matter what the solenoids are doing after pressure loss, there's no pressure force acting on the retarding side of the piston that is greater than the pressure force on the advancing side. The only options are:

1: Any combination of solenoids are open and therefore pressure on both sides of the piston is ~0.
2: All solenoids are closed and therefore pressure on advancing side is greater than pressure on retarding side.

Keep in mind that what I'm saying here is only applied for this case -- no vanos oil pressure.
OK, assuming the pistons were in mid point during OP drive before event happened. So both side of the piston had oil in the equilibrium state. Then vanos pump lost oil pressure, but in the dynamic of driving, DME still controlling the solenoids as it didn't know anything about the oil pressure loss, and so whenever the intake or exhaust solenoid valves were opened, the remaining oil pressure leaked out into the pan and no more oil pressure applied on the piston, and so eventually the only force applied on the piston is from the helical shaft, and with the cams rotating CW this caused the helical to push the pistons forward, retard direction.

[sapote]

The picture on red cart is what it is supposed to look like to get an idea of all the needle bearings and the cage material in the pan. The picture on the blue blanket is your vanos. I don’t know how that would of happened but the bearing race came out which is weird because the snap ring is still in place. I would recommend we drop the oil pan and get everything out just to avoid future issues. There is a screen on the oil pump pickup that would prevent anything from being sucked up but recommend removing to prevent any future issues. Let me know your thoughts.[/COLOR][/FONT]

I don't see your damaged vanos in the picture -- it's just a piece of the bearing. Where is the pic of the vanos with the snap ring and missing bearing race?
And what is the condition of the pump disk and 4 small pistons?

How do we know that the snap ring was still on the vanos with the bearing and races missing, or the snap ring was accidentally left out, and after some hundreds miles the bearing races finally walked out and BAM!
Let's assume the snap ring was left out, why the damage didn't happen in the next few driving trips? The bearing inner race has a deep groove for the 4 pumping pistons to ride on, and so the pistons are the ones that keep the bearing in place, until at some higher rpm then the race would walk out, by Murphy law.

[inlinesix123]

Did you get it all sorted out?

Yes!It's all good now, hang in there, light at the end of the tunnel!

[karter16]

Keep in mind that what I'm saying here is only applied for this case -- no vanos oil pressure.
OK, assuming the pistons were in mid point during OP drive before event happened. So both side of the piston had oil in the equilibrium state. Then vanos pump lost oil pressure, but in the dynamic of driving, DME still controlling the solenoids as it didn't know anything about the oil pressure loss, and so whenever the intake or exhaust solenoid valves were opened, the remaining oil pressure leaked out into the pan and no more oil pressure applied on the piston, and so eventually the only force applied on the piston is from the helical shaft, and with the cams rotating CW this caused the helical to push the pistons forward, retard direction.

Ahhhh I get it now! Thanks very much for taking the time to explain :-)

[bigjae46]

I saw it somewhere but where do we get a replacement needle bearing from?

[eacmen]

I saw it somewhere but where do we get a replacement needle bearing from?

Only source i'm aware of is Dr Vanos. Pricey though.