Technical BL Coil Investigation and Solution

[V8bait]

I don't care who does the printing or what material they use. 3D printing in this type of application to me is not suitable. Just more problems to look forward to in the future, even if it's better than current ones.

Defective on arrival vs failed after a year are both failures. These should be injection molded, or depinned, or cut/crimp/soldered. These are conversions, not temp fixes, treat them as such.

 

[fmorelli]

It will be interesting to see the new connector, which was made to solve the durability problem with the existing one.

Filippo

 

[The Convert]

I don't care who does the printing or what material they use. 3D printing in this type of application to me is not suitable. Just more problems to look forward to in the future, even if it's better than current ones.

Defective on arrival vs failed after a year are both failures. These should be injection molded, or depinned, or cut/crimp/soldered. These are conversions, not temp fixes, treat them as such.

3d printed parts can be just as good as injection molded parts, and more cost effective in low quantities. Injection molding on its own doesn't mean anything about the quality and capability of the part. Material properties are everything in an application like this, and you can get good properties in materials for both manufacturing methods. SLA, DMLM, DMLS, and other 3d printing technologies are capable of printing materials that would be plenty sufficient for coil connectors.

 

[V8bait]

3d printed parts can be just as good as injection molded parts, and more cost effective in low quantities. Injection molding on its own doesn't mean anything about the quality and capability of the part. Material properties are everything in an application like this, and you can get good properties in materials for both manufacturing methods. SLA, DMLM, DMLS, and other 3d printing technologies are capable of printing materials that would be plenty sufficient for coil connectors.

I disagree very much so. While not all 3D printing is equal, unless you totally mess up injection molding by choosing some useless plastic type, material for material it's always better. 3D printing is useful for testing, proof of concept, and temporary fixes. It's not good for parts exposed to constant things like high current, high temp, oil, stress and vibrations, etc.

 

[dyezak]

3d printed parts can be just as good as injection molded parts, and more cost effective in low quantities. Injection molding on its own doesn't mean anything about the quality and capability of the part. Material properties are everything in an application like this, and you can get good properties in materials for both manufacturing methods. SLA, DMLM, DMLS, and other 3d printing technologies are capable of printing materials that would be plenty sufficient for coil connectors.

This is as far from the truth as you can get.

 

[parksjm7]

Filippo and others who aided in this write up - thank you for the contribution.

Preface: I have a 2007 335i built September 2006. I'm using the Delphi version of the R8 coil, GN10446

Is it possible that there are different versions of the valve cover with different depths for the coil pack or my version of the coil pack contacts the spark plug at a lower depth compared to I applied the modifications on this thread I'm finding that in my case, the coils when engaged to the spark plugs were sitting higher on the valve cover than was shown here.

I did not take measurements, but I marked my stock coil pack with electrical tape when sitting at full depth and compared it to the R8 coil pack when sitting at full depth.



I'm thinking that it's the earlier version of the valve cover because the raised piece of plastic at the back behind cylinder 6 on my VC is quite a bit higher than what is shown here:
https://www.fcpeuro.com/products/bm...mT_g99ulfF1lTJYCe2KayC1g2Eu3YrI8aAkufEALw_wcB
And it prevents the Cyl 6 connector from sitting flush, although based on what I measured, the coil should still be in contact with the spark plug.

so TL;DR = is it possible that there are different versions of valve covers and R8 coils that don't require such extensive modifications?

 

[The Convert]

I disagree very much so. While not all 3D printing is equal, unless you totally mess up injection molding by choosing some useless plastic type, material for material it's always better. 3D printing is useful for testing, proof of concept, and temporary fixes. It's not good for parts exposed to constant things like high current, high temp, oil, stress and vibrations, etc.

This is as far from the truth as you can get.

Have either of you worked professionally with 3d printing equipment?

 

[dyezak]

There are limitations with 3d printing that are inherent and unavoidable no matter what. Even if you are jumping to the $100k+ poly laser machines. And for this particular application, the 3d printing limitations line up directly with the end product requirements.

The problem is on electrical connectors you have a very detailed print...that in itself isn't a problem as there are some really great machines that can get the appropriate detail. The compounding issue is that connectors like this have positive retention latches designed in. Latches that rely on plastic flexibility. Flexing a layered plastic in a thin area is going to be inherently more risky than a solid piece.

Add on to that the heat limitation. You have more options with GFR based plastics with injection molding that aren't compatible with any 3d printer. Think about a top mount turbo sitting next to an 3d printed plug.

If you are investing your money, and more importantly your reputation, on a product like this you look at the risks and it's fairly easy to conclude that for the small added monetary overhead and time commitment the elimination of risk and preservation of your reputation is worth it.

 

[The Convert]

There are limitations with 3d printing that are inherent and unavoidable no matter what. Even if you are jumping to the $100k+ poly laser machines. And for this particular application, the 3d printing limitations line up directly with the end product requirements.

The problem is on electrical connectors you have a very detailed print...that in itself isn't a problem as there are some really great machines that can get the appropriate detail. The compounding issue is that connectors like this have positive retention latches designed in. Latches that rely on plastic flexibility. Flexing a layered plastic in a thin area is going to be inherently more risky than a solid piece.

Add on to that the heat limitation. You have more options with GFR based plastics with injection molding that aren't compatible with any 3d printer. Think about a top mount turbo sitting next to an 3d printed plug.

If you are investing your money, and more importantly your reputation, on a product like this you look at the risks and it's fairly easy to conclude that for the small added monetary overhead and time commitment the elimination of risk and preservation of your reputation is worth it.

There's a simple solution to that problem and it doesn't require injection molding. One part is to print in a flexible material (formlabs has at least one that will work for instance), and another part is to use a thermal management product like a plug wire sleeve to isolate the connector, and a blanket on the turbo.

Good to see you have some background at least.

 

[dyezak]

There's a simple solution to that problem and it doesn't require injection molding. One part is to print in a flexible material (formlabs has at least one that will work for instance), and another part is to use a thermal management product like a plug wire sleeve to isolate the connector, and a blanket on the turbo.

Good to see you have some background at least.

But at that point you are trying to modify human behavior (you must use a turbo blanket, etc) and dictate variable outside your control.

Just injection mold it and you don't have to fight the PR battle.

 

[fmorelli]

Just injection mold it and you don't have to fight the PR battle.

Nice double entendre. And you might not have even noticed!

Filippo

 

[dyezak]

Hahah, I didn’t!!

 

[V8bait]

Have either of you worked professionally with 3d printing equipment?

Yes, I worked in a research lab for nearly 4 years doing tissue engineering and other various things and we used 3d printing extensively for many of our projects, all had to stand up to the autoclave heat but I still wouldn't trust anything that came off that printer for this application long term. I've never used an industrial printer but the one we had at MD Anderson was at least $100k and could be incredibly accurate.

 

[The Convert]

But at that point you are trying to modify human behavior (you must use a turbo blanket, etc) and dictate variable outside your control.

Just injection mold it and you don't have to fight the PR battle.

What percentage of people running a top mount aren't running a turbo blanket do you think? Supply the coil plug blankets in the kit. The behavior to want to thermally protect things is already there. That's why dei already sells plug wire blankets/sleeves.

 

[The Convert]

Yes, I worked in a research lab for nearly 4 years doing tissue engineering and other various things and we used 3d printing extensively for many of our projects, all had to stand up to the autoclave heat but I still wouldn't trust anything that came off that printer for this application long term. I've never used an industrial printer but the one we had at MD Anderson was at least $100k and could be incredibly accurate.

That sounds pretty cool. Industrial printers come in a lot of different flavors, as do the materials. 3d printing gets a bad rep because of all the cheap at home printers people are so familiar with, but what's available in industry is in a totally different league.

 

[doublespaces]

While this is a round shape unlike the connectors for the BL harness, 3d printed materials can be very strong. I decided to drive several times over a part I made the other day with my Chevy Volt. It is the inside portion of a Destiny Ghost I was printing but printed too small:

I'm confident I could drive over this with pretty much any vehicle, it would sustain multiple blows with a medium sledge before completely breaking, its 100% infill.

The problem with the BL connectors, has little to do with the 3d printing process, but instead the printing job was simply done incorrectly. There is a lack of bonding, the structure is fundamentally flawed. The settings are wrong, the nozzle may be partially clogged, print speed too high, the bed temperature may be wrong, filament quality may be poor, there are many different settings that can cause this to happen. Poor prints are very common, and the BL connectors are a good example of that happening.

 

[doublespaces]

For anyone curious this is my printer, its a Makerbot Replicator 2x clone with dual extruders

 

[langsbr]

What material were the BL plugs printed from? PLA? I wouldn't expect PLA to last in an engine bay at all, but ABS should be heat resistant enough I would think. Or maybe use some of that carbon fiber filament...awww yeah...

 

[fmorelli]

... or kevlar ...

Filippo

 

[Cheezy]

there are pry points on the connectors, when utilized they come apart fine. Small flat screwdriver and being careful, ive had mine in and out about 5 times without breaking them. First i depress/ pry the tab in the yellow circle, then i move on to separate the two connectors by prying in the gap in blue. After separating a little bit you can pull them apart. I think even the oem coil design had a depress/ pry mechanism, so we can't really expect these to not have a catch point. Of course if you dont depress it and pull hard enough it does break apart, probably shit printing process or adhesive, but problem is avoidable