Walnut Shells for Cleaning Intake Ports on DI Engines?

That's why they use walnut shells, they're not really that hard. The removed carbon chunks would be worse for the engine.

FWIW, if you do periodic cleans with sea foam or other top end cleaner through the pcv system, the walnut shells won't be required. I went through the cleanup with my wife's mini-S, the carbon build up was unbelievable. No detriment to performance that I could feel, however it eventually broke a valve and had to have a top end rebuild. I now run seafoam through it before every oil change to clean it up.

 

Interesting Pete. Have you looked at the back of the valves to see if the SF was effective? Also how are you using the SF? Are you putting it in the fuel tank as an additive or choking the car to stalling sucking it into the intake vacuum port. Letting it sit then starting the car?

 

The walnut shell blasting has been used since the mid 90's with no issues if done correctly. I used it a Ford for years. On some combustion chamber designs we were also using it in the chamber. We have even used it to clean combustion chambers in extreme cases with the intake removed.
The walnut chips will not harm the finish on the metal but does a great job on very hard carbon deposits.

Many manufacturers are now looking at going back to installing the equivalent of a cold start injector in the intake they can run periodically when the car is under WOT conditions to clean the intake and intake valves of PCV deposits. It should be interesting to see where this goes as these cars age.

 

I have not looked at them yet, but will at the next oil change with my scope (it's due soon). I put it in the PCV pipe from the valve cover that leads right to the intake with the car running and hot and pour at a rate to get the car almost to the point of stalling. I pour about half a bottle in slowly, keeping the car on the verge of stalling. In any case, it made it 120k miles before the valve issue, so the car will be over 200k miles before it's likely an issue again, and hopefully the sea foam treaments keep it from being the issue that finally kills it.

Putting it in the gas tank wouldn't do anything as being DI, the fuel never touches the intake valves which is why they gunk up in the first place. You have to pour it directly into the intake and the only real way to do it is through the pcv pipe.

 

John, I agree I don't care too much for the walnut shells. Yes its been used a lot but in the old days they used Bon Ami a lot to seat rings and people swore by that and that was dumb too.

Dry ice is a good idea if it is aggressive enough to do the job. In reality though the only cars we have had problems with so far had bad valve guides and maybe it is a better plan to just fix that problem. DI is new here so we shall see on those.

Are you in the gas turbine business? My father was to in a round about sort of way.

 

Dad designed stand by power for PT&T and AT&T. He also oversaw purchase and installation. Turbines were, during his tenure all the rage and I remember Solar being one of the companies he worked with. Most are being replaced by Diesels now.

 

+1. On my 09' S it stumbles and smokes when you pour the seafoam in but it seems to run a tad better once its done.. BMW has this silly vacuum and walnit shell tool that they use and charge like $1000 for the cleaning. I really like the dry ice idea.

 

It's funny how people make statements about the quality of the gasoline and implying it has something to do with the deposits.

 

It must be true

I saw it in a TV commercial.

 

Mercedes is testing a DI system that looks like something for surgery, their AMG's are carbon loading like no tomorrow.
Herd mention of CO2 also.

Minimally invasive surgery on engines, whats next?

 

I have done it many times on the BMWs and Audi's. It makes one hell of a mess. Clean up takes longer the doing the job.

It works very well. I had to do it on a Ferrari Cali. It needed injectors on the right bank, once I had the intake off the ports were pretty carbond up, so I blasted them. The owner couldn't believe the difference it made. Said it felt like a brand new car afterwords.

 

Turbines went micro! For primary power

What are MicroTurbines? | Brightergy

My interest as well, and there are several threads on it. For example:

http://www.ferrarichat.com/forum/florida-sponsored-ferrari-tampa-bay/341566-dry-ice-blasting.html

 

I should go dig my walnut shell/dry ice blasting thread from several tears ago.

Boy did I get blasted. Funny to see this again with some of the same players. LOL.

 

It's not DI that's causing the problem, per se. It's the pcv recirculating that oily crud.
A water or methanol injection system is supposed to reduce the buildup as well.

 

Would an oil catch can help? Or are they mostly hype?

http://oilcatchcan.com/

 

Some Mini people claim it helps.

 

Glad my new V12 is port injected.............

 

So I played with this a bit. I got a 20k mile 550M garage queen that has taken only short drives which is about the worst thing for a car. There is a bit more carbon on the intake valves that you want to see for that mileage. So I took the carbon off. It is really easy and this is my first pass cleaning the intake valves. They should be like new when finished. Some interesting facts, and a process: This is during my major. So my motor is #1 at TDC. Belts off cams out then all the valves are closed so this is an easy job. I experimented by putting just a teaspoon of carb cleaner in the bowl. I can back in an hour and it was still there. Those valves seal good! So I filled up the bowl until the valve face with carbon was submerged and let sit for an hour. Cleaning one port and it came out pretty good but still too much work. So I filled the other bowl and let stand overnight! In the morning the carb cleaner was still covering the valve. Nothing leaked into the cylinder! Now the carbon scrapes off like a sticky mess of goo that goes into solution. Then sop it up with a 2x2 gauze. Let dry then stick your shop vac in and your compressor blow gun and blow the carbon bits out while sucking them with the vac. Scrape off more carbon rinse and repeat and this is what you get. I think that walnut shell blast would be fine. The valves seal so well and you can blow out all the debris or reach it to loosen it with a tool then blow it out. So no probs getting stuff in the motor.
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Here is a link to another enthusiast site where a variation on the Sea Foam method is discussed: "Chinese Water Torture."

Chinese Water Torture (a SeaFoam recipe) - Turbobricks Forums

 

My 2010 458 with 55K miles. FNA told me they have no procedure for cleaning the valves so I'll use the BMW process myself with some modifications. Also having my injectors cleaned and flow tested while the intake is off. Should run even better than it already does! Pictures of the "after" results to follow.
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Those are some dirty valves, Mark. What brand of fuel do you use?

Looking forward to the "after" pics.