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Inlet valve cleaning

6K views 18 replies 10 participants last post by  puroalfista 
#1 ·
Direct injection engines typically need inlet valve cleaning performed regularly in order to preserve the performance of these engines. I would like to know:

How do you know when you car may be due for this kind of maintenance?
Any mileage recommendations?
If your car is running software, would you need to optimise it again after the clean?

In Cape Town this service is offered by C-Teq amongst others, who charge R2500 for a V6 and R1800 for a 4 cylinder. Is the expense worthwhile?

They use the walnut shell method and need to remove the intake manifold. Do they ensure that your valves are closed when blasting? How?

Diesel engines have been DI for decades. Would it be of benefit to have this done to a diesel as well? In my experience, DI diesels typically suffer from a loss of performance at between 80000km and 120000km. Could this be due to the same issue?

Thanks in advance.

PS: Would fitting a NOS wet kit clean your valves sufficiently? :cheese: It would cost a lot more but it would be loads more fun :devious:
 
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#4 ·
Isn't this what they used to call a 'strip and de-coke' in the old days?
I'm a bit sceptical, seems similar to the 'putting 2 stroke oil in your diesel' or the 'should I use Verimark Prolong' arguments.

I always judge these type of things by: If it's such a problem why aren't the OEM's recommending that we do it?

I'm not knocking the process as I've not really read up on the topic or seen it done for myself but personally I wouldn't want someone blasting any kind of abrasive substance into my engine...even if they assure me the valves are closed.
 
#5 ·
No it's not a strip and decoke. they used to have to pull the head for a proper decoke.

And 2 stroke oil in your diesel or petrol was for sticking rings and it still works today. It does noting for valves because diesel is also direct injection. In fact, quite recently I was chatting to someone about their 166 that lost compression in 1 cylinder and he completely cured it with 2 stroke oil.

And yes the OEM does this. They call Mario from C-Teq to come and do it in their workshops. That's how they make their money according to the email response I received from them.
Here is my previous email to them, and the response from C-Teq:

Sir/Madam,

I have an Alfa Romeo 159 V6 with a direct injected engine. It currently has 78000km and even though there is no discernible loss of performance, I would like to know what it would cost to have the intake valves cleaned? These engines are notorious for their carbon build-up.

What process do you use to clean the intake valves?

How long does this take?

Do you need to disassemble any of the engine? My car is still under warranty until 105000km and I would not like to lose the warranty because of unauthorised engine work.

Any additional information would be appreciated

Regards


Hi Ian,

Thank you for the inquiry.

Cost involved is R2500 for your vehicle. We only remove the intake manifold. The agents wont be able to pick up that the intake was removed. We have done many vehicles under motorplan with no issues at the agents. This is the core of our business.

We use a crushed walnut shell blasting method. This is the only 100% proven and safe method of performing the clean.

if you have any more questions, please contact me. oh sevin too sevin for sicks sevin for wun faaiv

Mario


The reason why I am interested is because we will easily spend tens of thousands taking a head off and polishing and porting but then allowing crud to build up. So what is the point of all the porting and stuff?
 
#6 ·
What I meant was it features among the many automotive placebos (Prolong, Turbo Flo etc etc) I wasn't comparing adding S2O as a direct alternative to walnut shell valve cleaning. When I referred to OEM I meant the parent company rather than a local dealer. I've yet to see an official manufacturer endorsing this solution. The same as them endorsing adding 2SO, or oil additives from Verimark or magnets that clip on your fuel line etc etc.

As far as adding two stroke oil is concerned the Car Magazine did a scientific study and found that mostly all 2S0 did was foul the injectors and choke catalytic converters.

Two-stroke oil - CARmag.co.za

Two-stroke oil - CARmag.co.za

So my point was...without scientific evidence to back it up one is really just shooting in the dark as far as what really works and what is a hoax. Just a thought wouldn't S2O cause more carbon fouling.
 
#7 · (Edited)
Oh sorry the 2 stroke oil treatment that I was referring to is where you add the oil directly to the cylinder through the plug hole and let it soak overnight to free sticking rings, not add it to oil.

Alfa Romeo was an OEM that actually performed intake valve cleaning on the 156's with JTS engines because they suffered from this issue terribly, due to being the first direct injection petrol engines. You can read about it here: Alfa Romeo forum: JTS low power problem resolved All OEM's are aware of this issue and the reason why the dealerships perform this is because of their head office circulars requesting them to do that. In order to get a payment for a motorplan repair, the dealership must receive authorization from the head office. So if they are cleaning intake valves on motorplan cars then they are being paid by the head office through their claim process.

OEM's will not endorse something if they are actively doing it because it then isn't an additional treatment but a required one. Like changing your oil. No oem will give you an endorsement stating that you need to change your oil. Because it is a requirement.

It is good practice to add an engine oil flushing fluid when draining old engine oil because it dissolves sludge and helps it leave the engine. However, this is also not endorsed by manufacturers.

The 1st pic below illustrates what the valves look like with carbon build-up. The second pic is of a modified inlet valve compared to a stock valve. With such minimal change an engine experience a good boost in performance. So how can all that carbon not affect performance?
 

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#11 ·
Hi Ian - I have had this done twice by a Carbon Doctor franchise in Gauteng after doing some research on this known phenomenon with direct injection turbo cars (with mileage above the 80,000 Km's) and the treatment (walnut shell blasting). I do not own a direct injection Alfa though so my research focused on the VAG and BMW cars - for a 2009 S3 and an 2008 E92 135i in our 'family' of cars. There were noticeable carbon deposits on both cars valves at 85000km's and 94000 Km's respectively (and both are out of motor plan). Saw the before and after pics of the valves and the clean was definitely effective and observable. Both car engine were smoother revving than prior (like they had a good old ol' days 'chune up'. S3 is now on 100000km's and still going like a sewing machine. The E82 (N54 engine twin turbo) continues to be the monster it's always been - at 118,000km. The latter runs JB tuning better dump valves and air cleaners and on the Std Map was recently dynoed at 265wkw and 540 NM. The carbon clean does involve manifold removal and the careful use of blasting and vacuum equipment - so it's all down to your level of comfort with the service provider and their care and attention to detail (like with most things). Carbon clean should not be compared with products that amount to little more than vacuous promises of 'Just pour in Cure/Power in a Can' - just like in the old days this is (mostly) rubbish. You can also have them check your valves first before blasting them but this does involve the expense of dismantling and some new gaskets if you consider you do not need it (yet). One things for sure, if you own a direct injection turbo car for long enough valve cleaning is on the menu somewhere down the line and proprietary carbon clean is the modern version of the old decoke and way less invasive.
 
#12 ·
There's also the Seafoam route. Very messy and probably illegal in some places. Isn't quite the same in terms of cleaning power but it may be a cheap alternative. Standard disclaimers apply ?.

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#13 ·
I cleaned my inlet on GQV...worked a charm. WMI also cleans inlet

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#15 ·
Anything injected before the valves will clean the valves, hence my comment on nos.

And this is not just occurring on turbo DI cars, but on all DI cars. Good to hear it actually makes a difference.

Anyone know if this is also beneficial for turbodiesels? Since they are DI as well.
 
#16 ·
I should imagine that even non-DI diesels could be prone to the issue, as they don't inject onto the back of a closed valve but rather into a precombustion chamber.

Non-DI petrols don't suffer this issue as the fuel flowing down the valve stem cleans/prevents deposits.


As a side note, I've used 2 stroke oil in the fuel to manage degraded valve stem seals. Mixed at 400:1, it totally prevented oil consumption vs circa 600ml per 1000km without premix.
 
#17 · (Edited)
My GQV has been running rough cold and noticeably hesitant at lower engine speeds. Consumption is also gone up close to 1.5L/100km since I bought it. Car has just touched on 100k km

I took it into C-teq yesterday for carbon clean. They do walnut shell clean method. Expected to get car back same day but got message in afternoon that the build up on two ports is so bad that they would like to soak overnight to get it softened up. I asked for before and after pictures. Keen to see but sounds like build up was really bad.
 
#19 ·
Didn't get me pictures in the end. The difference is very noticeable. I have no hesitation at all anymore. Rough cold starts are gone. The car pulls strong even sitting in 6th at just over 1000rpm. I had to gear down previously. Will have to see how consumption is but all shows seem to be to significant saving. Haven't had chance to open up yet but at slow engine speeds the difference is very noticeable and a lot more responsive.
 
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