n54 Intake valve cleaning

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Nick9one1

Member
 Newark, Nottinghamshire
Has anyone else on here had the intakes cleaned/walnut blasted? Seems like a pretty common thing for the N54.

I did mine today... no walnuts, but with carb cleaner, small brushes, rags etc.

Before
IMG_20181104_142901.jpg

After
IMG_20181104_172002.jpg

Not quite as clean as when walnut blasted but far better than they were :D
 
Wow, that's worked really well! Has it made any difference to the way the engine runs?

I think I'll do something similar next year as its inevitable with direct injection.
 
I was surprised how well they came up.

It definitely idles silky smooth now, it was ever so slightly lumpy prior to cleaning.
Not noticed a massive difference when driving but I've only taken it round the block.

I'll probably reset the adaptions in ista and see if that makes a difference too.

I've got an oil catch can to fit at some point - Hopefully it will reduce the buildup.
 
Nice pics. I’ve never clearly understood where all the carbon crap comes from on the inlet valves. Surely it’s just clean filtered air going in there, or is it becuase of the exhaust gas recirc / ccv garbage?
 
Thanks!

I think it's because of the ccv/egr (although the n54 doest strictly have egr).

To meet emissions standards manufacturers re-burn some gasses created by the engine. Traditional engines have the injectors before the valves, so the fuel 'washes' the ports keeping them clean. As the n54 is direct injection, any oil/carbon that is sent back into the intake from ccv/egr tends to stick.
 
Yeh, I understand why it's not an issue with port injection. If the source of the problem really is 100% down to crankcase ventilation systems then, you do wonder how hard it would be to disable / block the CCV operation to keep the whole intake side an awful lot cleaner.
 
Is EGR Delete a thing on these engines? I know it's common on MX5s and often done on diesels...
 
I had it done at the dealer for £250 while it was in for other warranty work. It's probably due another clean soon, might see if I can get a boroscope in without having to pull the entire inlet off.

I think a lot of the buildup comes from valve overlap during cruise conditions. With tuned cars it will be less of a problem as the overlap is removed as part of the VANOS table changes.
 
I will be doing this soon, just bought the car with 95K miles and previous owner never had it done and didn't know if it was done before his time. I have noticed at idle it 'skips' a bit from time to time, and I'm pretty sure this carbon build up is the cause of that. Otherwise the engine pulls like a bullet train.
 
Cees Klumper said:
I will be doing this soon, just bought the car with 95K miles and previous owner never had it done and didn't know if it was done before his time. I have noticed at idle it 'skips' a bit from time to time, and I'm pretty sure this carbon build up is the cause of that. Otherwise the engine pulls like a bullet train.
Click to expand...

I had the same, mine 'skipped' occasionally when at idle. The intake clean is worth doing, but I wouldn't expect it to cure this (it didn't for me).

If you've never had new injectors, I'd say they are the most likely cause. Especially when cold.

Next would be properly gapped plugs.
 
Nick9one1 said:
Cees Klumper said:
I will be doing this soon, just bought the car with 95K miles and previous owner never had it done and didn't know if it was done before his time. I have noticed at idle it 'skips' a bit from time to time, and I'm pretty sure this carbon build up is the cause of that. Otherwise the engine pulls like a bullet train.
Click to expand...

I had the same, mine 'skipped' occasionally when at idle. The intake clean is worth doing, but I wouldn't expect it to cure this (it didn't for me).

If you've never had new injectors, I'd say they are the most likely cause. Especially when cold.

Next would be properly gapped plugs.
Click to expand...

You say this didn't cure yours but yet when you first did it you said it was now running silky smooth ?? so did it cure it for a while then start idling lumpy again?
 
Yep it was the first time. I think the milage was about 90k when they were cleaned.

I plan to take the inlet off to see what they look like now at 100k.

I also added an oil catch can in the hope it would slow the build up.
 
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