Traits of a rebuilt double VANOS?

[Inur]

I have recently acquired a replacement 2nd hand double VANOS unit. Today we got down to swapping it on my car with the intention of rebuilding the old unit while running a replacement unit which we know will perform better in the mean time.

We removed one of the solenoid covers to find that the solenoids were embedded in a reddish polymer like substance. I'll get some pictures tomorrow, for now this badly modified image in Paint will have to do.

http://i.imgur.com/PR8XPbY.jpg

The only thing that springs to mind is that this unit has been tampered with and possibly rebuilt. Could this be a trait of a past rebuild?

[hakhawk]

sounds like the orings have failed and someones diy'd a fix by filling it with silicon

[Inur]

sounds like the orings have failed and someones diy'd a fix by filling it with silicon

That was my initial assumption. This is actually silicone so it's soft, doesn't have much sealing properties because it's cracked around the solenoids.
We have since dismantled my Vanos only to find the exact same compound/sealant under the solenoid cover. Both cars come from completely different countries.

I'm assuming based on what you've written that this is not a factory sealant and it shouldn't be there. I find it very odd that we now have two Vanos units with exactly the same fix.

[chriscotech]

What happened to the colour on that picture? It looks like Photoshop. It's hard to see how the silicone has been applied but it would be very hard to stop a leak on a 100 Bar hydraulic system like that. Was there any oil around? Maybe the previous owner was trying to dampen the sound of a noisy VANOS by stopping the case from resonating?

[M3kiwi]

This is the second time I've seen this,
A fellow bimmersports nz member found the same thing earlier this year.
When doing his rebuild

[Lysis]

That's definitely not how they come from the factory. My theory is that the silicone was put in there to keep the solenoids from moving around at all in an attempt to relieve any stress which the solders on the wires might be subjected to.

[Kornknarr]

This is very interesting. I have a MZ3 with the S50B32. When I bought it the dealer said that the vanos was repaired. To cut costs they had ordered a renovated unit. They sais it came from DrVanos. The repair was done by a BMW workshop. They state on the receipt that tha customer supplied the replacement.

Now I was not satisfied with how the engine was running and there was also a small oil leakege from the exhaust solenoid chamber. I ordered new o-rings and opened up the chamber and found exactly what you found. The whole chamber was filled with red silicone. It was the same in the intake chamber. I had no way to get the seller to take any responsibility and I had gotten the car cheap because of advanced subframe problems and had my hands full with that.

In September I bought the Beisan systems seal renovating kit and renovated the whole thing my self. The transformation in the cars behaviour was fantastic.

So there seems to be someone out there who enjoys filling vanos units with red plastics and fooling people and mistreat wonderful engines.

I have no receipt to prove that the replacement unit really was bought from DrVanos so they can be innocent here.

I can strongly recommend the Beisan kit!

Per, Sweden

[Kornknarr]

Btw this was how mine looked. Per

[chriscotech]

Maybe it is Dr Vanos that uses the red silicone. Can anyone confirm that?

I also rebuilt my S50 B32 vanos myself with the Beisan seal and anti rattle kits, as well as using the thicker S62 diaphragm springs on the cam sprockets. I'm very happy with the result too.

[kovrol]

my friend did the same 2month ago, everything was fine, I have to do it soon too.

[Inur]

Btw this was how mine looked. Per

Yes that's very similar to my units except the silicone wasn't so badly cracked. I have since shipped both units to VANO-Tech in Germany. I will drop them an email about this silicone, it's quite interesting that many cars seem to have this.


Edit:
Apparently the red silicone is a factory BMW fix which was applied to brand new units in the early years of S50B32 production.

[kevinwilly]

^Yeah, a LOT of them will have that red RTV silicone in there. And it's a total pain in the behind to clean out.

The newer S62-style solenoid orings have a flat on them and will pretty much fix the problem that the red silicone was meant to address. It wasn't there to really seal up oil leaks as it was to keep the solenoids from popping out of the holes. Every once in a while when the o rings get compressed, the solenoid will just shoot out of the hole they go into. This results in a MASSIVE oil leak and obviously a decrease in performance.

With the newer S62 o-rings, there's a lot more friction and this problem pretty much goes away.

[Kornknarr]

Interesting, but strange. Why would BMW's engineers propose such a method? If they wanted to keep the solenoid in place the silicone ought to have been applied on top of the solenoid and/or on the cover of the solenoid chamber. That would be in the direction of the force. And why would they advice a method that makes it a total PITA to service the unit? Is that a reliable source for that information? I'm not saying that it is not true, I just find it hard to believe, and would like some confirmation. That sounds like mechanics panicking.

[kevinwilly]

Whether it was done by BMW or not I have no idea. But it's definitely to keep the solenoids from popping out and leaking.

[Inur]

I would say the source is reliable, after all this comes from a business which specializes in Vanos rebuilds :) I have since received the unit and will post an update once tested. The car must have been down at least 100bhp considering it would not outperform a lightweight 328 in a straight line so the difference should be dramatic.