Metal VANOS Cover Failure - MUST READ!

Hey everyone,

Since my covers were mentioned in this thread — and since Chrisyphus shared his experience and insights earlier — I wanted to contribute some of the engineering background behind why I moved away from aluminum and switched to stainless. And thank you to Chris for the knowledge and transparency he always brings to this community.

When I first released aluminum S65 VANOS covers, they performed well for many users, and many are still running today. But over time, I began seeing scattered cases of tabs loosening or coming off — first on replica covers, then even a few from reputable brands. A customer of mine who purchased Aluminum covers from me eventually sent me photos of his own tab failure. Installation errors are always a possibility with snap-on covers, but I didn’t want to assume that was the only reason.

I pulled the aluminum covers off my website completely, even though I had a large amount of inventory left, and just took the loss. I’d rather bite the bullet and get real answers than keep selling something I wasn’t fully confident in.

I hired multiple 3rd-party engineering companies, including Performance Driven Design, and spent countless hours (and honestly, a lot of money) having them study the issue properly. After all that work, they all came back with the same general conclusion:

The S65 VANOS ring is a hardened steel component. Aluminum is much softer on the hardness scale, and when you have a hard steel locking surface repeatedly working against a softer aluminum tab over thousands of vibration cycles, the softer material can slowly start to wear away. It’s not dramatic and it doesn’t happen instantly, but that gradual micro-wear can eventually reduce the tension that keeps a snap-on cover locked in place. That’s the mechanism the engineering teams identified as the long-term vulnerability with aluminum in this specific location.

This doesn’t mean every aluminum cover will fail. But when a hardened steel locking surface works against a softer aluminum tab over many cycles, micro-wear can accumulate and reduce retention force.

Stainless steel, however, matches the durability and hardness of the VANOS ring, which removes that wear path entirely. That’s why every engineering recommendation pointed toward stainless steel as a more appropriate long-term material choice for this specific location.

When redesigning the stainless covers, two things were improved based on the findings:
• They are internally balanced, which helps minimize vibration transfer at higher RPM.
• The alignment/indexing features are much clearer, which helps prevent improper seating during installation.

At one firm’s recommendation, each production batch is also verified at a metrology lab with 40+ dimensional checks to ensure accuracy and consistency. It’s overkill, but it eliminates variation.

These stainless covers have been tested extensively in real-world conditions — both street and track — through heat cycling, vibration, and high-RPM load. Based on all testing so far, it is very clear that once these stainless covers are on, they do NOT come off.

For anyone running my earlier aluminum V1 covers: those can continue being used with periodic inspection as long as they are fully seated and show no movement. The stainless version isn’t a replacement for a defective part; it’s simply the final, more robust solution now that we have deeper engineering data. Anyone who wants to upgrade can do so, and I'll offer them the SS covers at cost.

To wrap this up: I’m not interested in going back and forth endlessly on this topic. I’m glad I was the first to offer an aluminum option stateside and help lower the price when the only alternative, which were the SLON covers, were around $900 a set. And I’m also glad to be the first to introduce a stainless steel design here. I genuinely hope other companies move to stainless as well, because based on everything we now understand, it is the right material for this application.


BTS with the SS Vanos Covers:
Metrology Lab Testing for Each Vanos Cover:

Thank you for finally saying all that Abdul. In future I hope you can keep an open mind when users provide feedback of your products. Not every bad feedback is a personal attack on your brand or product.

Thanks for sharing that, and I genuinely appreciate it. Just to clarify, I’ve never had an issue with people giving feedback. Anyone who has worked with me over the years knows I never take it personally. I actually take it seriously, because a lot of what I’ve built came from community input.

At the same time, I think it’s also fair to say that feedback goes both ways. People giving feedback should also know how to give it respectfully, constructively, and without turning it into personal attacks. I’ve seen that happen too often over the years, and it doesn’t help anyone. And just because someone has feedback doesn’t automatically make it correct. I’m always open to listening, but whatever direction we take has to be supported by actual science and engineering, not assumptions.

When we first made the aluminum VANOS covers, that was the industry standard. Every company making them was using aluminum, and based on the information we all had at the time, it made sense to follow that direction. I didn’t have the engineering resources or the technical expertise that I have access to today, so I didn’t have a way to independently test and verify things the way I do now.

That’s exactly why this situation unfolded the way it did. Once I started seeing issues and uncertainties, I didn’t want to rely on assumptions or forum theories. Instead of debating it or guessing, I pulled the product and brought in independent engineering firms to analyze it properly.

Now that I’ve taken the time to really plug into the engineering ecosystem around me here in the Motor City, my entire approach has changed. I’ve always lived here, but I wasn’t aware in the beginning of how many world-class engineering firms and testing facilities were right in my backyard. Today, I rely on them completely. I commission independent engineering companies for every critical decision, and I let their data guide the direction.

At the end of the day, I’m here to build the best possible parts for this platform. I’ll always listen to feedback, and I’ll always improve when something doesn’t sit right. Feedback is what starts the process. The engineering is what finishes it.

BenFenner So I ended up ordering the Ventrax covers, and learned after speaking with their designer, that they're actually made of 6082-T6 aluminum. Each weighs 34g on my Amazon Basics kitchen scale.

They're made overseas, which I asked about after placing the order, but it's a partner they've worked with for 10 years so make of that what you will. Just holding em in my hand they seem quality. I'll post this in your other thread as well. May see if they want to join the forum and this discussion, as they seemed happy to answer any questions.

Still have my Mporium cups, so not sure what I'm gonna go with when I eventually get around to doing valve covers.

Abdul wrote

Hey everyone,

Since my covers were mentioned in this thread — and since Chrisyphus shared his experience and insights earlier — I wanted to contribute some of the engineering background behind why I moved away from aluminum and switched to stainless. And thank you to Chris for the knowledge and transparency he always brings to this community.

When I first released aluminum S65 VANOS covers, they performed well for many users, and many are still running today. But over time, I began seeing scattered cases of tabs loosening or coming off — first on replica covers, then even a few from reputable brands. A customer of mine who purchased Aluminum covers from me eventually sent me photos of his own tab failure. Installation errors are always a possibility with snap-on covers, but I didn’t want to assume that was the only reason.

I pulled the aluminum covers off my website completely, even though I had a large amount of inventory left, and just took the loss. I’d rather bite the bullet and get real answers than keep selling something I wasn’t fully confident in.

I hired multiple 3rd-party engineering companies, including Performance Driven Design, and spent countless hours (and honestly, a lot of money) having them study the issue properly. After all that work, they all came back with the same general conclusion:

The S65 VANOS ring is a hardened steel component. Aluminum is much softer on the hardness scale, and when you have a hard steel locking surface repeatedly working against a softer aluminum tab over thousands of vibration cycles, the softer material can slowly start to wear away. It’s not dramatic and it doesn’t happen instantly, but that gradual micro-wear can eventually reduce the tension that keeps a snap-on cover locked in place. That’s the mechanism the engineering teams identified as the long-term vulnerability with aluminum in this specific location.

This doesn’t mean every aluminum cover will fail. But when a hardened steel locking surface works against a softer aluminum tab over many cycles, micro-wear can accumulate and reduce retention force.

Stainless steel, however, matches the durability and hardness of the VANOS ring, which removes that wear path entirely. That’s why every engineering recommendation pointed toward stainless steel as a more appropriate long-term material choice for this specific location.

When redesigning the stainless covers, two things were improved based on the findings:
• They are internally balanced, which helps minimize vibration transfer at higher RPM.
• The alignment/indexing features are much clearer, which helps prevent improper seating during installation.

At one firm’s recommendation, each production batch is also verified at a metrology lab with 40+ dimensional checks to ensure accuracy and consistency. It’s overkill, but it eliminates variation.

These stainless covers have been tested extensively in real-world conditions — both street and track — through heat cycling, vibration, and high-RPM load. Based on all testing so far, it is very clear that once these stainless covers are on, they do NOT come off.

For anyone running my earlier aluminum V1 covers: those can continue being used with periodic inspection as long as they are fully seated and show no movement. The stainless version isn’t a replacement for a defective part; it’s simply the final, more robust solution now that we have deeper engineering data. Anyone who wants to upgrade can do so, and I'll offer them the SS covers at cost.

To wrap this up: I’m not interested in going back and forth endlessly on this topic. I’m glad I was the first to offer an aluminum option stateside and help lower the price when the only alternative, which were the SLON covers, were around $900 a set. And I’m also glad to be the first to introduce a stainless steel design here. I genuinely hope other companies move to stainless as well, because based on everything we now understand, it is the right material for this application.


BTS with the SS Vanos Covers:

Metrology Lab Testing for Each Vanos Cover:

Interesting stuff
I wonder, how much do your SS covers weigh vs your old ally ones?

Per Abdul his SS units weigh ~308 grams for all four combined. Not sure about his previous offering but I would assume it is very close to Slon in this regard which are 95 grams for all four.
Additonal masses for other units found here: https://www.m3post.com/forums/showthread.php?t=2217377

a5m wrote

BenFenner So I ended up ordering the Ventrax covers, and learned after speaking with their designer, that they're actually made of 6082-T6 aluminum. Each weighs 34g on my Amazon Basics kitchen scale.

They're made overseas, which I asked about after placing the order, but it's a partner they've worked with for 10 years so make of that what you will. Just holding em in my hand they seem quality. I'll post this in your other thread as well. May see if they want to join the forum and this discussion, as they seemed happy to answer any questions.

Still have my Mporium cups, so not sure what I'm gonna go with when I eventually get around to doing valve covers.

Is it really important how much they weight? Is there any requirement?

Herofmine wrote

Is it really important how much they weight? Is there any requirement?

I only mentioned it for the data point. If you go back a few posts there was a discussion regarding added weight and its effects on the camshaft assembly. Essentially the additional weight is neglible.

a5m wrote

I only mentioned it for the data point. If you go back a few posts there was a discussion regarding added weight and its effects on the camshaft assembly. Essentially the additional weight is neglible.

It’s interesting… if that’s the case, it would be better to replace it with OEM plastic ones… if it’s calculated from an engineering perspective to be in a certain weight balance threshold.

I ordered from Abdul, once I get them will report on weight.

Herofmine wrote

It’s interesting… if that’s the case, it would be better to replace it with OEM plastic ones… if it’s calculated from an engineering perspective to be in a certain weight balance threshold.

I ordered from Abdul, once I get them will report on weight.

If they were available separately from BMW, then yes, but here we are.

His current versions are steel, so would be considerably heavier I'd assume. Sounds good, BenFenner can add it to his table.

I already added it, but confirmation would be great.

BenFenner wrote

I already added it, but confirmation would be great.

I got my Vanos covers from Europower

Weight - 79 g or 2.78 oz (I can tell the weight on heavier side)

Abdul wrote

Thanks for sharing that, and I genuinely appreciate it. Just to clarify, I’ve never had an issue with people giving feedback. Anyone who has worked with me over the years knows I never take it personally. I actually take it seriously, because a lot of what I’ve built came from community input.

At the same time, I think it’s also fair to say that feedback goes both ways. People giving feedback should also know how to give it respectfully, constructively, and without turning it into personal attacks. I’ve seen that happen too often over the years, and it doesn’t help anyone. And just because someone has feedback doesn’t automatically make it correct. I’m always open to listening, but whatever direction we take has to be supported by actual science and engineering, not assumptions.

When we first made the aluminum VANOS covers, that was the industry standard. Every company making them was using aluminum, and based on the information we all had at the time, it made sense to follow that direction. I didn’t have the engineering resources or the technical expertise that I have access to today, so I didn’t have a way to independently test and verify things the way I do now.

That’s exactly why this situation unfolded the way it did. Once I started seeing issues and uncertainties, I didn’t want to rely on assumptions or forum theories. Instead of debating it or guessing, I pulled the product and brought in independent engineering firms to analyze it properly.

Now that I’ve taken the time to really plug into the engineering ecosystem around me here in the Motor City, my entire approach has changed. I’ve always lived here, but I wasn’t aware in the beginning of how many world-class engineering firms and testing facilities were right in my backyard. Today, I rely on them completely. I commission independent engineering companies for every critical decision, and I let their data guide the direction.

At the end of the day, I’m here to build the best possible parts for this platform. I’ll always listen to feedback, and I’ll always improve when something doesn’t sit right. Feedback is what starts the process. The engineering is what finishes it.

Hi Abdul, I'm new to the community as I'm researching E90s with the goal of buying one in the Spring. I appreciate your candor and transparency. It sounds like you have a shop in Detroit, but I can't find the name of it. I'm sure it's listed somewhere obvious, but can you share the name of your shop so I can have a place lined up to purchase parts for when I buy my E90?

Thanks,
Mike

Herofmine wrote

I got my Vanos covers from Europower

Weight - 78 g or 2.78 oz

Thank you!

Your pic shows 79 grams, but your text says 78 grams. Can you clarify?

Or better yet, can you weigh all 4 of them at once and give that number in grams? I'm assuming these kitchen scales are going to be more accurate in this heavier range...

Either way, thank you for the info!

Seems I missed reading the previous page for some reason, interesting stuff!

Chrisyphus
A simple question, what does Tg mean?
Btw, I can attest to swarf burns, even though I haven't done any machining since college days (I'm 56 now), I still remember how hot that shit can be!
Random question for fun, very roughly, how much do you think (guess) a VANOS cover made out of titanium would cost?! lol (clip or bolt on).

More recently I wondered if the OEM covers have some sort of self lubricating, I know Nylon does, interesting to know the OEM covers PA66 does too, that does explain a lot. And thanks for your detailed explanations:), that must've taken ages to write!

***************

One thing I don't think I've seen anyone mention here (IIRC!), regarding (mainly) the weight of the bolt on covers, is the extra strain on the timing chains as the revs go up & down. Could that be a problem for the chains and guides in the long run??
(Whilst I questioned whether it could cause the bolts to come loose, which deansbimmer pointed out they're a LH thread, so can't, good point! I didn't think about the increase in rotational inertia at the time).

Btw, does anyone have some bolt on covers to hand to weigh?

Assimilator1 wrote

Seems I missed reading the previous page for some reason, interesting stuff!

Chrisyphus
A simple question, what does Tg mean?
Btw, I can attest to swarf burns, even though I haven't done any machining since college days (I'm 56 now), I still remember how hot that shit can be!
Random question for fun, very roughly, how much do you think (guess) a VANOS cover made out of titanium would cost?! lol (clip or bolt on).

More recently I wondered if the OEM covers have some sort of self lubricating, I know Nylon does, interesting to know the OEM covers PA66 does too, that does explain a lot. And thanks for your detailed explanations:), that must've taken ages to write!

***************

One thing I don't think I've seen anyone mention here (IIRC!), regarding (mainly) the weight of the bolt on covers, is the extra strain on the timing chains as the revs go up & down. Could that be a problem for the chains and guides in the long run??
(Whilst I questioned whether it could cause the bolts to come loose, which deansbimmer pointed out they're a LH thread, so can't, good point! I didn't think about the increase in rotational inertia at the time).

Btw, does anyone have some bolt on covers to hand to weigh?

Tg is the abbreviation that denotes the temperature at which a polymer will start to transition from a "glassy" (hard and solid) state to a soft, rubbery, and eventually liquid state.

The price of a Ti vanos cover would vary drastically, depending on the complexity of the cover- a clip-on, like most of these, would be.... obscene. I looked up billet prices.. I didn't call for any quotes, which would likely be 20%ish lower than online retail prices, but the material alone that we would need to make a set was $3300.


PA 66 is a Nylon. Nylon is just a specific flavor of PolyAmide, and the reason we all call it Nylon is the same reason we call cotton swabs Q-tips. It's Dupont's commercial name for this group of PolyAmides.

Always happy to share information when I have something valuable to add. Thankfully, it doesn't usually take too long, since I have all this bouncing around my head most of the time lol. Writing it all out on occasion is a good thought exercise that helps me contextualize and organize a bunch of information around a topic I have learned into a coherent, communicable manner, so it serves multiple purposes.

As long as the cover isn't significantly out of balance- multiple grams, like... egregiously off balance, it will have virtually zero effect.

Unless you're adding multiple kilos to the vanos covers, the added strain of accelerating them will absolutely pale in comparison to the load generated by turning the camshafts. Like... at least two, possibly more, orders of magnitude in difference of loads.

We've got some NRW covers in the Assembly room. I'll try to weigh them before I split for the weekend.


Great questions, and thanks for the appreciation. It means a lot to me that all of this writing is helpful to the community.

BenFenner wrote

Thank you!

Your pic shows 79 grams, but your text says 78 grams. Can you clarify?

Or better yet, can you weigh all 4 of them at once and give that number in grams? I'm assuming these kitchen scales are going to be more accurate in this heavier range...

Either way, thank you for the info!

Apologies for the typo earlier.

Each 79 grams, totaling 316 grams.

So, all my parts have arrived and I’ll be able to do the job tomorrow.

Valve covers, vanos covers, NRW gasket kit, and the throttle actuators.

Now, regarding the vanos covers, after reading all your comments and threads, I’m stuck in a dilemma. Should I keep the OEM ones in place, or replace them?

Herofmine wrote

Now, regarding the vanos covers, after reading all your comments and threads, I’m stuck in a dilemma. Should I keep the OEM ones in place, or replace them?

I would attempt to pry on one of them carefully, and if it flexes and can not be unclipped easily (it is still quite pliable), I would leave them in place.

This is exactly what I encountered, and wished I'd just left them alone for another ~45k miles. As it turns out, I cracked one of them upon removal, otherwise I'd be thinking about putting them back on...

If it shatters or cracks as you gently try to pry the first one off, then you have your answer. That's what I would do, and wish I'd been a little more careful and exploratory with mine when I was addressing them over a month ago . I just assumed at ~175k miles that they would be toast.

BenFenner wrote

I would attempt to remove them carefully, and if they flex and can not be removed easily (are still quite pliable), I would leave them in place.

This is exactly what I encountered, and wished I'd just left them alone for another ~60k miles.

If they shatter or crack as you gently try to pry the first one off, then you have your answer. That's what I would do, and wish I'd done over a month ago when I was addressing mine.

That’s what I was planning to do as well, my car at exactly 60k mileage and friends car at 50k as of now, I’ll be working on both cars this weekened let’s see I’ll update!

End up picking up valve covers from aliexpress, and compared quality of NRW (they are exactly same quality … local sore has nrw and billet versions for sale)

Chrisyphus wrote

Tg is the abbreviation that denotes the temperature at which a polymer will start to transition from a "glassy" (hard and solid) state to a soft, rubbery, and eventually liquid state.

The price of a Ti vanos cover would vary drastically, depending on the complexity of the cover- a clip-on, like most of these, would be.... obscene. I looked up billet prices.. I didn't call for any quotes, which would likely be 20%ish lower than online retail prices, but the material alone that we would need to make a set was $3300.


PA 66 is a Nylon. Nylon is just a specific flavor of PolyAmide, and the reason we all call it Nylon is the same reason we call cotton swabs Q-tips. It's Dupont's commercial name for this group of PolyAmides.

Always happy to share information when I have something valuable to add. Thankfully, it doesn't usually take too long, since I have all this bouncing around my head most of the time lol. Writing it all out on occasion is a good thought exercise that helps me contextualize and organize a bunch of information around a topic I have learned into a coherent, communicable manner, so it serves multiple purposes.

As long as the cover isn't significantly out of balance- multiple grams, like... egregiously off balance, it will have virtually zero effect.

Unless you're adding multiple kilos to the vanos covers, the added strain of accelerating them will absolutely pale in comparison to the load generated by turning the camshafts. Like... at least two, possibly more, orders of magnitude in difference of loads.

We've got some NRW covers in the Assembly room. I'll try to weigh them before I split for the weekend.

Great questions, and thanks for the appreciation. It means a lot to me that all of this writing is helpful to the community.

Ah, interesting to know that PA66 is a form of Nylon! Btw, I've never head of Q tips, must be a US thing .
I'll put aside £6000 for some Ti VANOS covers then!

I didn't mention anything about balance re VANOS covers , just wondered about the inertial load, more so the solid bolt on covers rather than the various clip on ones. But yea good point about the force required to turn the cams, occasionally doing engine work myself I know there's practically no chance of fully turning a cam by hand! (valves and springs installed).

Are the NRW VANOS covers the bolt on type?

Herofmine
If you plan to test the covers like BenFenner mentioned, then make sure you won't need to drive the car if you need to get new covers. If they were as fragile as mine, even being really gentle they cracked anyway! They were extremely fragile and brittle!
Personally if I were you and undecided as to what covers to go for currently (my choice now would be the SS covers), I would remove the valve covers and visually inspect them only, don't touch them! If they look ok, chuck it back together and replace them as and when you've decided what covers to go for. If they're cracked, then you'll have to bench it.

Btw visually checking the valve covers isn't going to tell you the quality of the materials. Who made the aliexpress ones?

Assimilator1 wrote

Ah, interesting to know that PA66 is a form of Nylon! Btw, I've never head of Q tips, must be a US thing .
I'll put aside £6000 for some Ti VANOS covers then!

I didn't mention anything about balance re VANOS covers , just wondered about the inertial load, more so the solid bolt on covers rather than the various clip on ones. But yea good point about the force required to turn the cams, occasionally doing engine work myself I know there's practically no chance of fully turning a cam by hand! (valves and springs installed).

Are the NRW VANOS covers the bolt on type?

Herofmine
If you plan to test the covers like BenFenner mentioned, then make sure you won't need to drive the car if you need to get new covers. If they were as fragile as mine, even being really gentle they cracked anyway! They were extremely fragile and brittle!
Personally if I were you and undecided as to what covers to go for currently (my choice now would be the SS covers), I would remove the valve covers and visually inspect them only, don't touch them! If they look ok, chuck it back together and replace them as and when you've decided what covers to go for. If they're cracked, then you'll have to bench it.

Btw visually checking the valve covers isn't going to tell you the quality of the materials. Who made the aliexpress ones?

Aliexpress ones are valve covers

Vanos covers as above posts I purchased from Euro Power, it’s made of stainless steel very sturdy, I have no trust to aluminum ones that offered by various vendors

Herofmine wrote

Aliexpress ones are valve covers

Vanos covers as above posts I purchased from Euro Power, it’s made of stainless steel very sturdy, I have no trust to aluminum ones that offered by various vendors

You got my questions back to front , I was asking who made the valve covers....