Metal VANOS Cover Failure - MUST READ!

I’m going to be installing Carbahn, but I absolutely prefer Mporium.
Different strokes for different folks, I guess

Move Over wrote

Not a bad idea. I typically grab each clip with a set of Chanel locks with a microfiber towel and snap them against the vanos gear. I usually don’t reccomend this to others as I don’t want to responsible for when someone’s slips and grinds up their gears, lol.

Grinding my gears really would grind my gears if I am being honest.

Here's a different approach to correcting this problem, although it seems the whole VANOS unit has to come out.

https://mehenker.com/pl/regeneracja-regulatorow-faz-rozrzadu/338-regeneracja-vanos-bmw-m3-40-s65-v8.html

Notice that they change the spring posts and install mushroomed ones. That way the spring won't be able to walk itself out, and you eliminate the need for the cap altogether.

DRLane wrote

So we’re now operating from “I showed pictures to random engineers and they said these look more substantial” as meaningful contributions?

Starting to feel like I should be selling parts to some of you.

i'm still pretty convinced that if people just took the time to rotate the crank and made sure everything was actually clipped on, we wouldn't have this long of a thread.

rantarM3 wrote

Here's a different approach to correcting this problem, although it seems the whole VANOS unit has to come out.

https://mehenker.com/pl/regeneracja-regulatorow-faz-rozrzadu/338-regeneracja-vanos-bmw-m3-40-s65-v8.html

Notice that they change the spring posts and install mushroomed ones. That way the spring won't be able to walk itself out, and you eliminate the need for the cap altogether.

This is in my eyes the obvious way the spring lock should have been desiged in the first place. BMW engineers are obviously clever but I simply can't understand this one.

So I had to do some service on my passenger side valve cover and had to pull it due to a faulty install of the spark tubes(another shop) and had my shop fix the issue and had him check the vanos covers and they are all clipped in. I’m assuming that the driver side is the same. They have been on the car for about 13k miles and have had 3 track days.

I do think the fear of something catastrophic happing spreads like wild fire and sometimes causes mass hysteria. I jumped on that boat when the first incident of the plastic vanos covers happened. I bought the first batch of SLON covers and installed them when I did the valve cover maintenance.

After seeing this thread I again jumped on the boat and was checking my oil fill cap at 2:30 in the morning trying to see if the clips were on.

After seeing that the vanos covers are still holding strong it somewhat puts me at ease. But I’m going to pick up a set of mporium covers incase by chance a clip does come off I’m changing those out asap. lol

I feel like after reading everything it’s just a matter of when it happens.

But here’s some pics of the covers on my passenger side

gh0stE92M3 wrote

After seeing that the vanos covers are still holding strong it somewhat puts me at ease.

From your photos it looks like a couple of the clips are coming loose, no? They're not sitting flush against the hub, it seems.

I wonder whether these clip-on style covers are unbalanced, and when rotating at high speed flex outwards where there is more mass, causing the clips to work themselves lose on that side.

My SLON covers are going to sit on my shelf even longer now.

rantarM3 wrote

From your photos it looks like a couple of the clips are coming loose, no? They're not sitting flush against the hub, it seems.

I wonder whether these clip-on style covers are unbalanced, and when rotating at high speed flex outwards where there is more mass, causing the clips to work themselves lose on that side.

My SLON covers are going to sit on my shelf even longer now.

Been reflecting om this but simply by feel and bending on the covers I found it very hard to believe those few grams on the clip end could start sway away. Also quite narrow diameter and "only" 4k speed I assume.
Gyess fairly straight forward to make a rough calculation assuming we knew the tip weight/mass.

Helmsman wrote

Been reflecting om this but simply by feel and bending on the covers I found it very hard to believe those few grams on the clip end could start sway away. Also quite narrow diameter and "only" 4k speed I assume.
Gyess fairly straight forward to make a rough calculation assuming we knew the tip weight/mass.

yeah depends very much on the actual weight, but it can be surprisingly material. 2 grams at an 8cm radius (made that up, don't know what it actually is) and 8400 rpm is 25lbs of force.

https://www.omnicalculator.com/physics/centripetal-force

kolosy wrote

yeah depends very much on the actual weight, but it can be surprisingly material. 2 grams at an 8cm radius (made that up, don't know what it actually is) and 8400 rpm is 25lbs of force.

https://www.omnicalculator.com/physics/centripetal-force

I have wondered about centrifugation affects myself. Even when using this conservative calculation 2g tip weight assumption from kolosy and Helmsman's ponderings - then if it takes less than 25lbs of force (from the calculation above) to mount the clip tips into position, then centrifugation 'might' be causing the clip tips to relax radially. It's speculation combined with some engineering math, but this 'might' explain why different metals should do better than others.

For example: steel and aluminum have different thermal expansion rates, different spring rates, different fatigue lifes and have different mass i.e. steel is heavier than aluminum. Moreover, not all covers use the same finger and tip design or thicknesses. Thicker tips are heavier, but also stronger to resist centrifugation depending upon the metal being used. The OEM, MPorium and Carbahn 'cup' designs mitigate centrifugal forces by using a solid piece and circumferential cup rim.

does anyone have a slon cover sitting near by? can one of you measure the width, length and thickness of one of the locking clips?

and ideally the diameter of the whole thing...

kolosy wrote

yeah depends very much on the actual weight, but it can be surprisingly material. 2 grams at an 8cm radius (made that up, don't know what it actually is) and 8400 rpm is 25lbs of force.

https://www.omnicalculator.com/physics/centripetal-force

Don’t forget that cams spin half as fast as the crankshaft, so more like 4200 rpm.

Got tired doing the rod bearings last night…write up for the timing is coming! Promise.

Weight and balance was a big factor for me installing the Mporium on mine. It felt better when you compared it to Carbahn’s simple washer design.

Centrifugal force and heat are the two factors that influenced me to sell my SLON covers. The aluminum would significantly conduct more heat than the OEM plastic.

Thermal expansion has to be bad for things “clamped” onto something spinning all the time.

Do you use the same bolts when you add the washers or do you get extended bolts? The threads not going in as far as before doesn’t affect it backing out or the torque procedure?

kolosy wrote

does anyone have a slon cover sitting near by? can one of you measure the width, length and thickness of one of the locking clips?

and ideally the diameter of the whole thing...

I have my set in a closet. If you post a marked up photo of what you’d like measured, I’ll give it a try.

I have a set of Mitutoyo metric dial calipers that I would use.

e92dud wrote

Do you use the same bolts when you add the washers or do you get extended bolts? The threads not going in as far as before doesn’t affect it backing out or the torque procedure?

Same bolts. The depth is pretty much the same because the washers are not used. The Cup/Plate acts as a washer.

Two day shipping from the UK. If anyone is interested here are the measurements.

Nice. Is that a thickness of 2.13? If so, that’s a rough volume of 300 mm^3 which for aluminum should translate to about a gram for the clip. At 4200 rpm, and a radius of 4.5cm that’s a centripetal force of about 2 lbs. doesn’t sound like enough to move it on its own, though maybe in conjunction with vibration and heat disparities?

After reading the first post I had to check through the oil cap. Looks OK. The next time I have to pull my blower off I will check the driver side. I went with SLON covers.

If these vanos covers are subject to such high stress that the clips could fall off, I am sure the plastic one would have exploded and caused many engine failures already.

I for one think it's an installation error or faulty batch. I doubt the vanos covers are subjected to such high levels of strength that the clips would de-latch themselves.

Or the vanos covers were not machined properly from the jump and the dimensions are off with Slon and the replicas that were failing.

kolosy wrote

Nice. Is that a thickness of 2.13? If so, that’s a rough volume of 300 mm^3 which for aluminum should translate to about a gram for the clip. At 4200 rpm, and a radius of 4.5cm that’s a centripetal force of about 2 lbs. doesn’t sound like enough to move it on its own, though maybe in conjunction with vibration and heat disparities?

The width of each clip is aprox 22.35mm and the depth of each clip is only 1.15mm if I measured correctly which seems very small to me.

I've been following this all week and finally had some time this weekend to dig up some memories. Full disclosure, when this problem was widely discovered back in 2021 I gave in to the hysteria and parked my car for the better part of the a month in fear my 13 year old covers would suddenly crumble away now that I was aware of it. I bought used VANOS units to harvest the OEM covers and learned a couple things when playing around with the spare adjustment gears.

The OEM covers were extremely frail however were very tight on the unit regardless. Removing them is a tedious process of disengaging the clip with a pick and gently walking the cover around the unit with a flat head. The reason these failed was due to material failures - the plastic would warp in heat and clips would disengage, or plastic covers would warp enough to hit other moving parts and break off. It's a combination of these two elements that provided failure and terror to owners (my summary of what i saw in various posts and searches). Keep in mind that these clips are literally no bigger than a grain of rice

I went with the Slonik route because it was more economical, and because i was anticipating problems trying to re-time my 150k S65 engine. Felt like i would at least give the covers a try. When i test fit the covers on a spare unit, i was very impressed with how tight these engaged the unit with only 3 clips fully installed. In the end Slonik covers fit like a glove and i have no worries about them staying on. I agree with GORDON.M3 gh0stE92M3 and feel most of these failures are actually install and knock off failures.

I am curious about the material degradation suggested in this thread. I'm no engineer, but i would imagine Slonik and others DO have engineers on their teams and would anticipate thermal properties of the materials used in the final design. Almost all metals expand in some way, thought this is standard knowledge in any fabrication industry and compensated for appropriately. Either way, I'm sure we'll all find out sooner or later.