VANOS Sticking? Can't figure out the problem

[sapote]

I am of the thought that the “internet advise” of using S62 diaphragm springs on the S54 VANOS hubs is actually a bad idea

So what is the reason people used the S62 spring? Part of the anti-rattle scheme or to reduce the actual position error?

[maupineda]

So what is the reason people used the S62 spring? Part of the anti-rattle scheme or to reduce the actual position error?

I don’t think there is a valid one, both diaphragm springs are in compression state, one would have more preload than the other, but since both are under preload, neother would rattle, one just makes the system overcome higher force which the system was mot designed for.

[sapote]

I don’t think there is a valid one, both diaphragm springs are in compression state, one would have more preload than the other, but since both are under preload, neother would rattle, one just makes the system overcome higher force which the system was mot designed for.

Was Beisan advocating for the S62 change? I have not seen any evident that the stock spring washer at fault.

[Shonky]

S62 springs definitely stopped the rattle on mine which is the reason given for using the. Very noticeable during the VANOS test with the hood open. What that actually means to performance I'm not so sure though.

[eacmen]

Was Beisan advocating for the S62 change? I have not seen any evident that the stock spring washer at fault.

Beisan does advocate for the S62 springs in their anti rattle:

https://www.beisansystems.com/procedures/s54_vanos_rattle_procedure.htm

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[mleveroni]

So I was just able to pressure test the vanos. I used the Lang Racing tester so the accumulator was disconnected. In the quick video I watched on someone testing it, they had it sitting around 1500psi, which makes my results confusing. I am getting 1500psi only when cranking then it quickly drops to ~500psi, then when I shut the car off it shoots back up to 1500psi quick. The pressure regulator in the solenoid is new but the pressure regulator that goes into the back of the vanos unit has never been replaced. Is that pressure valve my issue? Just confused on why it is making the correct pressure while cranking then dropping once it is running.

Edit: Just tested with the solenoid unplugged and pressure does not drop so is it possible my solenoid is bad even though it is new?

[maupineda]

You should have 100 bar or 1450 psi at any steady rpm speed, whether idle or redline.

it would slowly drop when shutting the engine down from 100bar to 40, then it would drop off quickly.

During cranking it shall have low pressure as pressure build up gradually, maybe within 20 seconds after engine start.

your values don't make sense.

[eacmen]

So I was just able to pressure test the vanos. I used the Lang Racing tester so the accumulator was disconnected. In the quick video I watched on someone testing it, they had it sitting around 1500psi, which makes my results confusing. I am getting 1500psi only when cranking then it quickly drops to ~500psi, then when I shut the car off it shoots back up to 1500psi quick. The pressure regulator in the solenoid is new but the pressure regulator that goes into the back of the vanos unit has never been replaced. Is that pressure valve my issue? Just confused on why it is making the correct pressure while cranking then dropping once it is running.

Edit: Just tested with the solenoid unplugged and pressure does not drop so is it possible my solenoid is bad even though it is new?

I don’t understand why the accumulator is disconnected for this test?


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[sapote]

I am getting 1500psi only when cranking then it quickly drops to ~500psi, then when I shut the car off it shoots back up to 1500psi quick. The pressure regulator in the solenoid is new but the pressure regulator that goes into the back of the vanos unit has never been replaced. Is that pressure valve my issue? Just confused on why it is making the correct pressure while cranking then dropping once it is running.

1. If you got to 1500 psi then the regulator AND the pump are good.
2. But then why it dropped to 500 with engine running? Leaking piston seals or solenoid valves is the root cause -- making the valves leaking when engine running with DME controlled the vanos.
3. Recover back to 1500 during engine shut off? Again, pump still turning so pressure built up to 1500 as DME turned off the solenoid valves.

[sapote]

I don’t understand why the accumulator is disconnected for this test?

He just want to measure the pressure by the pump and regulator, so I don't think the ACC is needed as the engine doesn't need to change the timing rapidly which needs the ACC for backup reservoir.

[Cubieman]

My aftermarket disc made acceptable pressure until the oil warmed up, I hope OP let it idle to the first dot on the oil temp gauge to see if pressure remained the same as when first started with cold oil.

Also, I looked at the Lang pressure tester, it looks like maybe you can test what I figured the "regular" way w/o having to remove the accumulator, right?

[maupineda]

why remove the ACC? it is pointless, bear in mind it is a closed-loop system so the pressure is the same anywhere in the system. the ACC is just a reserve of oil at pressure to maintain pressure constant. when the solenoids operate there will be pressure drops, there is when the ACC supplies oil at pressure to keep it "steady". Removing the ACC would only make those drops more notable, which you can see on the gauge when blipping the trottle.

[mleveroni]

My aftermarket disc made acceptable pressure until the oil warmed up, I hope OP let it idle to the first dot on the oil temp gauge to see if pressure remained the same as when first started with cold oil.

Also, I looked at the Lang pressure tester, it looks like maybe you can test what I figured the "regular" way w/o having to remove the accumulator, right?

The Lang Racing tester does not look like this, it simply removes the ACC line and replaces it with another line going to a gauge. This is the only reason for removing the ACC.

[mleveroni]

1. If you got to 1500 psi then the regulator AND the pump are good.
2. But then why it dropped to 500 with engine running? Leaking piston seals or solenoid valves is the root cause -- making the valves leaking when engine running with DME controlled the vanos.
3. Recover back to 1500 during engine shut off? Again, pump still turning so pressure built up to 1500 as DME turned off the solenoid valves.

I was thinking the same thing now. I am going to try a new solenoid since that is easy. However if the problem still remains it has to be leaking through one or more of the seals right? I followed the Beisan procedure for the seals exactly and everything went smoothly, but I can't think of anything else that would be the issue.

[mleveroni]

Update: No luck with a new solenoid. Just going to send the whole vanos unit to Dr. Vanos to be rebuilt and tested.