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SIDI Intake Valve Cleaning?

gonebytim

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Hi,

I’ve done a lot of reading (a lot of it from threads on here) about the issue of Carbon build up in the intake valves of the direct injection V6.

I understand exactly why it happens and I’ve installed a Catch Can and even cleaned out the PCV valve at the rear of my LLT engine.

Thing is - I purchased the car with 240,000km on it and judging by the carbon build up people were claiming to see at 30,000km or less (plus YouTube videos I’ve watched of direct injection engines getting major carbon build up at low km) - I believe that my engine would have to be stuffed full of carbon build up.

some videos I’ve watched showed people getting back 20% of their horsepower after cleaning the carbon deposits (demonstrated before and after on the dyno).

the one thing I haven’t figured out - is the best way to get the valves cleaned?

there are other videos of people using all the “top of the line” intake valve cleaning chemicals to try and clean the carbon - and demonstrating that these chemicals do nothing to remove the hardened carbon deposits.

then I saw videos about how BMW uses a method called “walnut blasting” to clean the intake valves, and that they have special equipment that fits into the valves of the BMW and blasts out the carbon getting the valves back to brand new looking and that BMW Service Centers all have this equipment and even built it into the cars service schedule.

because it seems like this is a coming issue for the LLT and LFx Sidi engines - I called Holden to see what they offer as a service and they told me that they do some sort of chemical flush of the intake valves for $160.

considering that all of the Internet believes that walnut blasting - or alternatively- pulling the top of engine off and spending 10 hours hard par our scraping the crap out of the valves - to be the only solutions that work.....

....a $160 flush at the Holden Dealer seems a bit “too good to be true” if it works and gets the car back to running like new again (it’s currently a bit sluggish compared to my other car which is the exact same model but has half the km on it).

so I’m wondering if anyone here has had any experience with getting their SIDI engine valves cleaned out properly or if anyone has even payed Holden for the valve clean?

Or if anyone here is a mechanic who offers the service - id love some information.

cheers
 

syked

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Yes I believe walnut blasting will be the the best solution but is quite labour intensive. There's a mechanic in Drummoyne (Sydney) that offers this service and does it regularly for all types of direct injection. The mechanic workshop is called "313 Automotive"

I've also personally had good results with seafoam. You can spray it in via a vacuum hose but I took off the inlet manifold and sprayed it directly at the valves. Might be worthwhile changing spark plugs and oil soon after this though.

There's also a company that does a carbon clean using water (yes I know it sounds weird) but the science makes sense. Check out http://www.enginecarbonclean.com/how-it-works/
 

mechanic

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There are two different problems that you've eluded to in your post. It's important to separate them.

1. Exhaust soot coating the intake tract - this is seen in diesel engines due to their high-use of EGR to cool down the combustion temperature to stop oxides of nitrogen forming. This symptom is minimised by adding an oil vapour separator. Petrol engines do not generate anywhere near as much soot as a diesel, so generally don't suffer from this symptom (nor do they require a vapour separator - it will catch oil, but this oil will otherwise do no harm to your engine).

2. Carbon buildup on the back of the intake valve - some manufacturers and direct petrol injection engine designs suffer badly from this, some don't. GM SIDI engines are lucky in this respect and generally aren't affected (and if they are, it's localised to one cylinder due to a localised fault). An oil vapour separator does nothing to slow/stop this if your engine is prone to buildup.

Subaru are one manufacturer that knows they have an issue with this. They schedule an intake cleaning foam at every service interval. This is made by 3M and is available at Repco etc. Though, if you haven't used this regularly it won't work after one application - that goes for all engines.
 

rambunctious

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What about water injection using the water/oiler injection kits.
Simple kit involving a water bottle in a bracket with adjustable drip tap and hose.
Hardest part would be working out the best vacuum connection to connect to.
 

BowTie

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Subaru have an aerosol foaming upper engine cleaner that I have used for years.

Penrite do one now too but haven't tried it.

Without egr they work great.

On intakes with egr, not so great for build up but good for keeping it clean once it is.

Penrite do a complete fuel system cleaner that claims to clean the inlet valves a bit. Have tried that but can't tell if it has done anything.
 

Fu Manchu

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Subaru are one manufacturer that knows they have an issue with this. They schedule an intake cleaning foam at every service interval. This is made by 3M and is available at Repco etc. Though, if you haven't used this regularly it won't work after one application - that goes for all engines.

I have long used this stuff on all my cars since owning Subaru's. Always bought it from Subaru as Subaru top end cleaner. From this, I'd assume the 3M product is sold as a different name at Repco?

I know many in the automotive industry swear by it. (Subaru Top End Cleaner)
 

mechanic

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I'd assume the 3M product is sold as a different name at Repco?
I've had a brain-fart.

I've just looked and it's made by Threebond. (I knew it was three-something).

Threebond engine conditioner
 

syked

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Penrite do a complete fuel system cleaner that claims to clean the inlet valves a bit. Have tried that but can't tell if it has done anything.

Not sure how this helps a direct injection engine? The fuel injectors are lower than the valves (i.e petrol sprayed directly in the combustion chamber on the piston) so this stuff won't even go anywhere near the valves meaning it's pointless for cleaning carbon build up on valves on a direct injection engine.
 

VS_Pete

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I got this mob to do mine they were doing a car at work.
The only way I can describe it car was going 90% performance.
I can only think PCV had carbon.
After treatment all good.
https://enginecarbonremoval.com.au/

I did do a oil change about a month after but it was needed anyway.
I do 7500K oil changes and the oil wasn`t bad about the same.
 
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Fu Manchu

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I have been stuffing around with misting water slowly through the top end every now and then.
Certainly no harm so far.
 
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