Epoxying injector bungs into a plastic manifold

[z1 zonly]

Hi all. I'm interested in drilling and epoxying/plastic welding/otherwise bonding injector bungs into a Porsche Cayenne manifold, which is made of plastic. I've Googled around and see that there's precedent for epoxying bungs into aluminum manifolds, but it's difficult to find for plastic. Is this a reasonable and safe exercise? Can i use any old aluminum injector bung, or should I make sure it's of a similar material?

 

Here's a pic of the manifold in question:

 

[LLave]

You may want to look into direct port nozzles, you can add fuel and nitrous to an existing injector bung. This would probable be more reliable than epoxy on relatively thin plastic.

 

http://www.hotrod.com/how-to/engine/direct-port-nitrous-efi/

 

http://nitrousdirect.com/wetnitrouskits.html

 

Good luck with your project. 

[NewZed]

It's probably made of nylon or polypropylene, with glass fiber reinforcement.  Difficult materials to adhere to.  A mechanical fastening method might be better.  You'll dull some tools on the glass, drilling holes.

[z1 zonly]

You may want to look into direct port nozzles, you can add fuel and nitrous to an existing injector bung.

 

The difficult thing is that there are no injector bungs.  These models had their injectors way down in the head and no bungs on the manifold.  I need to add some for my project.

 

 

It's probably made of nylon or polypropylene, with glass fiber reinforcement.  Difficult materials to adhere to.  A mechanical fastening method might be better.  You'll dull some tools on the glass, drilling holes.

 

Not sure I can get away with mechanical fastening, because I just don't know how much material there is to deal with, particularly at an angle to get injector spray parallel to the intake charge.  It's a $300 gamble to get a manifold and find out.

 

Argh...

[NewZed]

Actually, it looks like Loctite might have some good adhesives.  Not epoxy, but cyano-acrylates, aka "super-glues".  401 looks like it might work.

 

http://microfluidics.cnsi.ucsb.edu/processing/237471_LT2197_Plastic_Guide_v6_LR7911911.pdf

 

http://www.na.henkel-adhesives.com/us/content_data/382071_LT3355_ASB_v19_2015.pdf

 

Buy a cheaper manifold from a wrecking yard to practice on.  Might not be exactly the same material but should have similar machining properties.  Many later model cars have composite manifolds.

[LLave]

The difficult thing is that there are no injector bungs.  These models had their injectors way down in the head and no bungs on the manifold.  I need to add some for my project.

 

 

 

Not sure I can get away with mechanical fastening, because I just don't know how much material there is to deal with, particularly at an angle to get injector spray parallel to the intake charge.  It's a $300 gamble to get a manifold and find out.

 

Argh...

 

Perhaps  you can epoxy resin a bit of a build-up in the location you want a nozzle, sand it flat, then use one of the threaded fogger nozzle mounts:

http://www.amazon.com/NOS-17283NOS-Brass-Nozzle-Mounting/dp/B000COXFVU

[z1 zonly]

Seems like about the same end result as bonding in a bung, no? And it'll be difficult to get a nut on the back side at a ~30-45deg angle to the runner.

[Tony D]

You need to determine the plastic used. It will be on a symbol on the manifold per CE recycling requirements.

The issue is some plastics will 'weep' and any glue used on them will eventually lift. Like PE. 

In this case, you 'plastic weld' bungs of sufficient thickness and then drill/tap the manifold to accept what you want.

 

Once you know what the manifold is made from, you can determine bonding and joining techniques.