First off I have to thank Texasmontego and gawannamini for their outstanding writeup's on intake cleaning. If your considering doing this make sure to read them. Just mainly wanted to share my results and a few pointers or ideas I picked up along the way.

So here's Tigger pre-op


You can do a lot of tool fabrication and trial and error or just buy the tools BMW makes for the job. Picked these up from our friends at ECS Tuning.



You'll also need a portable spot blaster or media blaster of some kind. Here's a $40 e-bay special that I used.



Now the only problem is adapting the BMW nozzle to our portable unit. Luckily this model also came with a steel nozzle. If you have something similar you can take it to a machine shop and adapt it. The threads on the BMW part are M14 1.5 as I recall and the nozzle had to be turned down to .5178 before threading the outside and chamfering the inside. This is what it looks like after machining.



This is the final product once it's assembled.



Then the fun part. Taking the intake off. As noted before in the other writeups the biggest PIA is getting the #*^$ing boost line off of the intake. After being installed for 49K miles it pretty much said bite me when I tried to remove it. If you run into similar just separate the boost tube at the slip joint, remove the upper half and just leave the lower half attached to the intake. It will come out fine with it still on. One other point to make here. Once everything is disconnected you can rotate the intake back but there is one final bolt at the bottom holding the intake on. It is the 10mm bolt that they hung in the air and built the car around. Working on aircraft I'm used to working blind but its still a pain with just a jack and jack stands.



It's all downhill and easy after this. Especially if you have two other tools on hand. A 1" hole saw and a video boroscope or similar remote viewing device. You'll want to cut a hole in the felt fender lining on the passengers side inline with the bolt holding the harmonic balancer on. This will help you rotate the engine by hand with a socket and ratchet later to close the valves prior to blasting. Getting walnut shells inside the combustion chamber falls under the heading of "Thing's not to do today".



Since I had access to one I used a 4mm articulating boroscope to see in the intake as I rotated the engine. Homedespot and Lowers both sell inexpensive ones that do the job just as well.



The other piece of advice I have is to cover the ports your not actively cleaning. The walnut media is a fine grit and after blasting and vacuuming the intake ports some media will still be left and require blowing out. Covering the ports keeps it out of any ports where the valves may be open. See note above about things not to do.



So what does it look like when your done? Below are before and after pictures of the individual ports and valves.

















And since I was in there I figured why not take a peek at the plugs and in the cylinders to see what kinda shape their in. Little bit of buildup after 49K but not too bad. Plugs are going pretty soon anyways before I install the JB+.





Was it worth the knuckle bustin and occasional foul word or twelve.... Definitely! The idle is now silky smooth and the throttle is much crisper and responsive. Hope this helps anyone else interested in doing this. Happy Motoring.

 

Sweet write-up, thanks.

Question though, I hear meth injection helps with carbon build-up. Do you think it'd help enough to never need this?

 

Good question. I don't run meth myself and I imagine it would slow but not stop the buildup. Perhaps one of our meth lovin brothers can give us a better answer.

 

Sincere thanks for a truly great write-up. The pictures are priceless.

 

Methanol will prevent build up, not clear it up. In other words if you have carbon build up, clean it then install a methanol kit and you'll be good.

 

Wow thanks for the education. Quite the eye opener. How much time did you spend cleaning?

 

Second. I notice you had a pretty common amount of build up, with one looking to be quite bad compared to the others, wondering how long to get everything cleaned to nearly new as you did.

 

It wasn't bad at all. Start to finish about 3.5 hours including initial setup and clean up afterwards. Probably could do it in about 2 hours now but I prefer to take my time when performing a task for the first time.

 

Sounds like I may need to look into one of these. It would also compliment the JB+ pretty well. What I'd really like to do next is pull the valve cover off and trace the passages for the internal PCV path. Looks like they dump into the beginning of the intake port.

Perhaps its possible to alter the valve cover gas path to close those ports and direct it through the external PCV hose. This would finally make catch cans of value on the N18.

 

Glad to see its not bad at 49K.

 

Thanks for the pictures! I'm at 70K and considering doing this soon. I'll probably be b/w 120-150K by the time I make it back to WMW and I'm not sure it's a good idea to wait... I drive about 35K/yr, so that's 1.5-2 yrs from now...

Does anybody else live in the south? It's SO freaking humid here that I'm wondering if my valves are as dirty as y'all driving in dry climates. If water/meth helps, then surely high humidity doesn't hurt? Thoughts? I suppose I need to just take the intake off and physically inspect the valves.

 

Nice job , first I have seen on the N18 engine write up.

 

Thanks for this!

 

Judging by the pics, the valves looked to be in "good" condition. There was not the very heavy buildup that is typical on the backside of the valve and stem, like you would see on a N14. Good to see..btw thank u for taking the time on the write up

 

Interesting. I reached kind of the opposite conclusion: that this shows that carbon build-up IS still an issue for the N18, despite what some might say (I'm guessing that's partly because not that many are high mileage yet, but who knows). Did he mention the mileage? I didn't see it. Since it's a 2011, I'm guessing it might not be up to the 60k or so when you see the really bad valves on the N14.

Regardless, it's a great post. I think it just convinced me to give this a shot myself.

 

49k miles according to the borescope pics

 

Yes it's at 49k and change. I'd say carbon buildup is better on the N18 but not gone based on buildup I've seen on N14's.

I'm a bit of a perfectionist (probable explains why I work in quality control) and anything that impairs efficiency and performance puts a bug in my bonnet. That's why when my warranty runs out at 55K the valve cover is coming off. Then I can evaluate the internal PCV system to see if it can be improved.

Glad to see this post has encouraged others to give it a shot. It's not difficult and for what the dealer charges its a no brainer.

BTW there was only a slight oil film in the rest of the inlet and next to none accumulated in the old FMIC before the Forge unit was installed. But then again most of our cars aren't under boost that often which is when the secondary PCV system is active.