Doing an Intake Valve Clean - any tips?

[enzed4]

As the title says, I will be attempting to clean the intake valves this weekend prior to fitting a new fmic and charge pipe, and remapping.
There are plenty of youtube vids online, I've found what looks like a good one for a 335i that shows all of the steps, but was wondering if anyone here has done it and can offer any tips that might help save me any pain/frustration?
I will be using the CRC intake cleaner - have one can, hopefully this will be enough.
What method do you use to move the valves into the closed position? The video looked a bit sketchy using a wire across the starter motor but if this is the normal method I guess it will do. Also, it seems like a good idea to remove the spark plugs as well, to blow out any residue after cleaning (and removing as much as possible) rather than letting it fall into the cylinders, but the video only mentioned this after he found wet plugs post clean.
I tried to get this done professionally but wasn't happy with what was on offer (I think it was that hydrogen clean which reviews seem to show doesn't do a thorough job). No one does walnut blasting that I could find.
Thanks.

[R.E92]

Wire across the starter is the normal method for DIY. If you take the plugs out before blasting you're more likely to end up with crap in the cylinder, probably best to leave them in place.

I had mine done about 40k miles ago, the dealer did it for £200 while it was in for an MOT so i didn't bother going through the hassle of a DIY. I'll inspect it again soon and see how bad they are after 40k miles, I'm hoping that because of the reduced valve overlap in my tune that it won't be as bad.

[Chippie]

I did mine a few months ago, take spark plugs out as this will also allow the engine to turn over easier, just make sure you cover it he holes with plenty of rags, I used the wire on the starter motor,
I also used a cheep sand blasting kit with the walnut shells as well as the cleaner and some oven cleaner to soften the deposits, you may find one can won’t be enough, I also used a small syringe with a short piece of rubber pipe to suck the crap out before using compressed air to get them clean

[scootr]

How many miles on your car? Last intake valve cleaning?
Another reason to love the N52

[enuff_zed]

How essential is this?
Does it apply to all models?
Is this due to direct injection and therefore not getting petrol hitting the back of the valves?

[scootr]

How essential is this?
Does it apply to all models?
Is this due to direct injection and therefore not getting petrol hitting the back of the valves?

Apparently yes. Direct injection does not wash fuel over the backside of the intake valve allowing for buildup of carbon deposits on the seat surface etc. The NA engines can use a fuel additive like Liqui Moly to combat the problem. Which can be much cheaper and easier to use.

[enuff_zed]

How essential is this?
Does it apply to all models?
Is this due to direct injection and therefore not getting petrol hitting the back of the valves?

Apparently yes. Direct injection does not wash fuel over the backside of the intake valve allowing for buildup of carbon deposits on the seat surface etc. The NA engines can use a fuel additive like Liqui Moly to combat the problem. Which can be much cheaper and easier to use.

Thanks. Something to bear in mind for the future then.

[scootr]

How essential is this?
Does it apply to all models?
Is this due to direct injection and therefore not getting petrol hitting the back of the valves?

Apparently yes. Direct injection does not wash fuel over the backside of the intake valve allowing for buildup of carbon deposits on the seat surface etc. The NA engines can use a fuel additive like Liqui Moly to combat the problem. Which can be much cheaper and easier to use.

Thanks. Something to bear in mind for the future then.

I read every 40-45k miles. 72k km

[Pbondar]

How essential is this?
Does it apply to all models?
Is this due to direct injection and therefore not getting petrol hitting the back of the valves?

When I had my mega service by B for BMW in January I asked for them to do the walnut blast..they said, on the N20 engines with less oil blow by that in their opinion it was a waste of time before 75k miles...I practically begged but they said it was a waste of my money..

Obviously depends on many factors..type of driving, fuel used, duration of trip etc etc..

[enuff_zed]

How essential is this?
Does it apply to all models?
Is this due to direct injection and therefore not getting petrol hitting the back of the valves?

When I had my mega service by B for BMW in January I asked for them to do the walnut blast..they said, on the N20 engines with less oil blow by that in their opinion it was a waste of time before 75k miles...I practically begged but they said it was a waste of my money..

Obviously depends on many factors..type of driving, fuel used, duration of trip etc etc..

And as one of the N20-owning elite ( ), I shall follow your advice. Thanks

[enzed4]

How many miles on your car? Last intake valve cleaning?
Another reason to love the N52

50,000mi / 80,000km. No history of intake valve cleaning (not part of BMW scheduled service AFAIK).

How essential is this?
Does it apply to all models?
Is this due to direct injection and therefore not getting petrol hitting the back of the valves?

Reading many threads and looking at videos online it seems to be a very common issue with the N54 engines. As mentioned by Scootr, the DI engines don't get fuel washing over the back of the intake valves and get a carbon build up, usually manifesting as a rough idle and lack of power. Once clean many owners fit a catch can to reduce the build up in future. I probably should, but don't actually see keeping the car long enough to justify it. (famous last words). I'm not really keen on DIY'ing it, but I might as well learn something and see how bad it is (or isn't) for myself.
I will probably take some before/after pics and post when done.

[enzed4]

I did mine a few months ago, take spark plugs out as this will also allow the engine to turn over easier, just make sure you cover it he holes with plenty of rags, I used the wire on the starter motor,
I also used a cheep sand blasting kit with the walnut shells as well as the cleaner and some oven cleaner to soften the deposits, you may find one can won’t be enough, I also used a small syringe with a short piece of rubber pipe to suck the crap out before using compressed air to get them clean

Thanks for the tip re the syringe and rubber pipe .
I now have one vote for remove spark plugs, and one for don't remove them. Doesn't make my life any easier

[Chippie]

Here’s a couple of photos of before and after I did mine at 60000 miles

4749E4CB-390C-4FE8-8367-1406F29CE104.png (834.94 KiB) Viewed 1193 times

D2EDA403-7640-4751-8ABC-4FFA5F7C6D25.png (1.08 MiB) Viewed 1191 times

[scootr]

I'd bet you might be able to turn her over by hand without the plugs? Worth a try, just grab the fan and turn once the plugs are out... you are replacing plugs now too? I was going to suggest you take pics of everything you are going to remove - for yourself. Having watched the manifold removal on line I see a bunch of stuff needs disconnecting. That can get confusing for not much DIYer guy upon reassembly

[Yal]

My favorite BMW tech here in town has done a number of these. He offered to walk me through it, so will probably do that sometime this year... I don't mind doing my own wrenching as long as I have a good source of info. Beer, pizza and engine work, should be a fun day. Will be putting in a catch can as well.