Valve Stem Carbon Build-up from Oil in DI Engines

[PimTac]

Originally Posted by jqgz
Just a thought. Instead of running seafoam down the intake tract, couldn't one just run gasoline? Much cheaper, similar solvency. I think this could definitely be a good top engibe intake-tract-fed cleaner for GDI




Give it a shot and let us know how it turned out.

 

[ka9mnx]

Originally Posted by PimTac
Originally Posted by jqgz
Just a thought. Instead of running seafoam down the intake tract, couldn't one just run gasoline? Much cheaper, similar solvency. I think this could definitely be a good top engibe intake-tract-fed cleaner for GDI




Give it a shot and let us know how it turned out.

Have the fire department on speed dial...

 

[skyactiv]

Depending on the engine, taking the intake manifold off and cleaning the intake valves.. isint that hard. I did it on a VW GTI I once owned.

 

[nicholas]

Please don't spray gasoline into the intake.

 

[nicholas]

Go buy a pro duct designed to clean intake valves through the intake.

 

[ChrisD46]

*How much of a contribution to reducing intake valve deposits is there by using a D1 / Gen 2 synthetic oil at a conservative OCI (less than 5,000 miles) in a GDI engine ?
*How much of a contribution to reducing intake valve deposits is there by using a top tier gas in a GDI engine ?

The above are fairly easy things for a GDI engine vehicle owner to do - but not sure how much they play a role in keeping GDI engine intake valve deposits at bay ?

 

[Olas]

DI or PFI is not the issue - polluting your inlet tract is the issue. Don't dirty your inlet and you won't dirty your valves. Simples.

 

[Denkun]

I've had great success with a catch can on the pcv side and a small maintenance dose of Lucas top end lube mixed with tc-w3 at every fill up. Once a year I'll add some redline si1 or some other high pea cleaner like Techron or regane. During the winter I add some Lucas ethanol shield since I don't drive as much. I use the same concoction in my snowblower and the carb, piston, spark plug are very clean. Fuel pump in my cars are noticeably quieter. One car has a slight piston slap noise reduction. I don't see how using this modern engine oil will fix that valve carbon. If anything it'll just grow more since carbon attracts more carbon. Especially on HM engines with worn out valve seals and more oil consumption. Only bandaids that have worked for me is catch cans and additives, if I had a GDI I'd start on day one.

 

[Denkun]

Originally Posted by thunderchild
I have a BMW X5 3.0 si. I have the DI engine. What is the best way to keep the carbon buildup off the top of the valves? I am looking into the Seafoam treatment. Does anyone have any ideas on how to maintain this?


Properly baffled catch cans. Remove the manifold and clean the valves beforehand. Using a quality oil and changing often to reduce consumption. If you still get deposits you can add a second catch can on the pcv to filter out what the first one misses. Fuel additives will not help you since they won't touch the valves on DI. Seafoam through an intake vacuum line could work. If you want a constant cleaning you can consider adding meth injection. Which will spray methanol —kind of like how nitrous works— into your intake. The mist provides a performance boost and will clean slightly. Using a high mileage oil like max life will help keep your valve seals in good shape

 

[pschnahc]

IVDs are just like the deposits under your valve cover- they were once volatile, nasty gaseous vapours that have condensed into a solid on something cooler like aluminum intake runners, plenums, ports and intake valves. This has been happening since engines.
Everything changed with newer plastic composite (low specific heat, low thermal conductance) intake tracts from throttle to port and the removal of valve fuel washing (GDI), crankcase vapours have little to condense onto until the intake port, and once there, the port and valve have little/nothing to wash them. And suddenly IVDs are a thing. The higher the operating temperature of the valve, the less likelihood of the vapours condensing on it to begin with where they can be spent in the combustion process. Another solution has been using two fuel delivery systems simultaneously. The reduction of volatile, ash-forming Phosphorus additives as an effort to protect catalysts has also IMO inadvertently helped the IVD problem.

Catch cans are good for mists and oil spray but have a limited capacity to precipitate dirty vapours. To filter IVD causing vapours properly, they would need to be routed across a large, cool surface area.

 

[ejes]

I know they are a dying breed, but how about just not buying a vehicle with a DI engine? There are compromises all throughout life. Deal with what you will. Personally, when I buy a new vehicle, that is a major deal breaker with what I chose to put my hard earned money towards. That's why I replaced my 15 year old Dodge pickup with a Tundra last month instead of with one of the big 3 . Old tech, but proven.

 

[john_pifer]

Originally Posted by Olas
DI or PFI is not the issue - polluting your inlet tract is the issue. Don't dirty your inlet and you won't dirty your valves. Simples.


This.

The main sources of intake tract carbon fouling are:

1. EGR. Just swipe your finger along the exhaust tip of your GDI vehicle to see how much unburned carbon is put out by the rich mixtures created by the DI system for cylinder cooling and anti-detonation. This is being sucked back through your intake and gets deposited on your valves and intake tract just as it does on the exhaust tips. In fact, it's worse, due to oil mist from the PCV system getting the valves all wet and sticky.

2. PCV. It's sending oil vapor and mist back through. And, obviously, higher-SAPS oils leave more deposits. This is why lower-SAPS oil is a good idea for these engines. And, the lowest Noack volatility rating oil, because, the more stable the oil is, the less vapor it will send back through the intake, and the fewer deposits. Also, a more stable oil will resist fuel dilution better.

The inherent fuel dilution that comes along with GDI (and especially TGDI) engines just makes things worse because when you add a solvent to the oil (gasoline), you effectively raise volatility, and lower the temperature at which the oil starts to off-gas these volatile vapors that condense in the intake tract.

Someone suggested using an MB 229.5-certified oil, which will have lower SAPS as well as Noack volatility rating of
Which...as someone else mentioned...it's weird that the VME 0W-20 (which I just bought a BUNCH of from the AZ clearance) is pretty high Noack at 12% or so.

 

[ChrisD46]

Less IVD by running a monthly "Italian Tune Up" ; not letting engine lug below 2,000 RPM's while driving to keep valves hotter ?

 

[john_pifer]

Originally Posted by ChrisD46
Less IVD by running a monthly "Italian Tune Up" ; not letting engine lug below 2,000 RPM's while driving to keep valves hotter ?


I'm sure it would help, but who's gonna drive like that all the time? You can't.