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Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: SubieRubyRoo] #4999209 02/02/19 08:35 AM
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Originally Posted by SubieRubyRoo
So the only way to prevent PCV vapors from contacting the backside of the intake valve is to either eliminate PCV; move to a system like a valve cover evacuator like race cars use that suck it directly into the exhaust; or to suck it out of the crankcase and compress the snot out of it, and then direct-inject it directly into one of the cylinders. That would prevent all fuel and oil from entering the intact tract...


My 3.5 five cylinder Colorado does not have a PCV. Not sure how it operates without it.


19' Hyundai Santa Fe 2.4 GDI - Valv Syn 5w30 / Napa Proselect filter / 6oz Liqui-Moly
20' Kia Soul X-Line 2.0 Multi-port / Factory-fill oil / filter
04' Colorado 3.5 / Castrol Edge 0W40 / K&N filter
Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: EngineeringGeek] #4999325 02/02/19 10:23 AM
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StevieC Offline
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It will have a breathing system instead. It has to have one or the other or the engine would explode from pressure.

Last edited by StevieC; 02/02/19 10:23 AM.

'18 Caravan - 45k KM - AMSOIL SS 0w20, Fram Ultra, TC-W3 500:1
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There is no such thing as "lifetime" fluids! mad
Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: Mainia] #4999437 02/02/19 11:55 AM
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Originally Posted by Mainia
Originally Posted by EngineeringGeek
Originally Posted by MolaKule
Engine oils and fuels are hydrocarbons.

A particular oil or fuel may reduce carbon deposits, but my bet is on the physcis that says anytime a hydrocarbon is burnt or subjected to high temperatures, there is no way it can eliminate or prevent carbon deposits.

The fuel never touches the backsides of the valves so that makes no difference in a D.I. engine although that's another common myth as it does have an impact with conventional port injection. But the oil vapors/mist/blowby/etc. from the crankcase DO contact the backs of the intake valves and that's the root of the problem. How much of that mix, and resulting deposits, are attributable to the oil is the key question. There does seem to be some consensus conventional oils leave more desposits than fully synthetic. But, as others have pointed out, what makes for a better synthetic is less clear even if Valvoline claims a 30% reduction with their Modern Engine formulation.


I respectively disagree with you, fuel will touch the backside of the valves in the valve overlap cycle. This could be why some cars carbon up more then others, Other variables are, engine bore size/cylinder head C chamber shape/cam timing & profile/port design/ignition mapping.


I was going to say the same thing. It is design issue.... some engineers have successfully designed fuel wash while the intake valve is open. Some have obviously failed and it also explains why a software update was part of the solution for engines that had a propensity for carbon formation on intake valves.

I'd still feel better with port injection but let's not pretend that all DI engines are going to have this problem. There are engineering solutions that have nothing to do with oil. They have to do with where/when the fuel is injected and design of the combustion process. A catch can and high NOACK oil are not the issues.

Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: StevieC] #4999512 02/02/19 01:19 PM
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Originally Posted by StevieC
It will have a breathing system instead. It has to have one or the other or the engine would explode from pressure.


I'll wear my Iron Man outfit, driving that non-PCV Colorado to 5:00 PM Mass. Then I'll light a candle and sprinkle that 4X4 with holy water.
That should keep myself safe thru the weekend, while running chores in that Colorado.


19' Hyundai Santa Fe 2.4 GDI - Valv Syn 5w30 / Napa Proselect filter / 6oz Liqui-Moly
20' Kia Soul X-Line 2.0 Multi-port / Factory-fill oil / filter
04' Colorado 3.5 / Castrol Edge 0W40 / K&N filter
Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: EngineeringGeek] #4999516 02/02/19 01:25 PM
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One way to clean the backside of the intake valves is to use carb and intake cleaner and spray it down into the intake while someone holds the throttle at 4k RPM, and spray the entire can. Then change the engine oil. That will also clean the intake manifold. I also clean the MAF sensor every oil change with MAF sensor cleaner

Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: Bullwinkle007] #4999856 02/02/19 08:35 PM
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Originally Posted by Bullwinkle007
One way to clean the backside of the intake valves is to use carb and intake cleaner and spray it down into the intake while someone holds the throttle at 4k RPM, and spray the entire can. Then change the engine oil. That will also clean the intake manifold. I also clean the MAF sensor every oil change with MAF sensor cleaner

I've seen zero independent proof any spray works. If you've ever seen and felt carbon build up on a D.I. intake valve it might as well be black concrete. So, no surprise, sprays, Seafoam, etc. don't seem to do much to magically soften and dissolve rock hard baked on carbon build up. There's a reason manufactures usually only recommend mechanical cleaning methods such as walnut shell blasting. Sprays don't work and there are plenty of independent tests that show they don't work.

@KevinP there is no "fuel wash" of the back side of the intake valves in a D.I. engine from all the research I've done. When the intake valve is open you have nothing but air and PVC vapors flowing IN to the cylinder and ideally nothing flowing the other way. The last thing you want for fuel efficiency is having raw direct injected fuel going back into the intake manifold where it would be wasted and that would also require some sort of reverse flow which would be hard to induce. Everything about efficient combustion for maximum fuel economy, lowest emissions, and greatest power, opposes dumping raw fuel mixture back into the intake manifold. i think it's a myth. If someone has factual evidence to the contrary I'd love to see it?

Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: EngineeringGeek] #4999942 02/02/19 11:35 PM
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I don't have pictures but I have seen the difference in the Veloster I'm maintaining with it.


'18 Caravan - 45k KM - AMSOIL SS 0w20, Fram Ultra, TC-W3 500:1
'06 Santa Fe - 535k KM (Retired)

There is no such thing as "lifetime" fluids! mad
Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: EngineeringGeek] #5005855 02/09/19 02:10 PM
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Quote

@KevinP there is no "fuel wash" of the back side of the intake valves in a D.I. engine from all the research I've done. When the intake valve is open you have nothing but air and PVC vapors flowing IN to the cylinder and ideally nothing flowing the other way. The last thing you want for fuel efficiency is having raw direct injected fuel going back into the intake manifold where it would be wasted and that would also require some sort of reverse flow which would be hard to induce. Everything about efficient combustion for maximum fuel economy, lowest emissions, and greatest power, opposes dumping raw fuel mixture back into the intake manifold. i think it's a myth. If someone has factual evidence to the contrary I'd love to see it?


That is not completely true. The best example would be in an Atkinson cycle engine where combustion contents are partially forced back up the intake and these lead to BETTER fuel efficiency, not worse. What is washed up into the intake is not lost, it is used the next time you open the intake valve.

https://www.caranddriver.com/news/a...bustion-cycle-and-what-are-its-benefits/

https://www.youtube.com/watch?v=WKKILW3Zj_Y

https://www.youtube.com/watch?v=z45fM2N-4C4

And note.... Toyota engine management allows a vehicle to use both Otto & Atkinson operation in a non-hybrid. That would mean they would get fuel/air mixture on the back of the intake valve at least part of the time, presumably allowing for more intake valve cleaning.

Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: KevinP] #5005929 02/09/19 03:41 PM
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Additionally Toyota uses DS4 injection in multiple Engines. This means there is both port and direct injection. Based upon power demand. Most of the normal driving time the port injection is supplying a little squirt the traditional way, while direct injection operates at a lower rate. Under heavier load demands it switched entirely to direct injection.
Meanwhile The intake valve opening overlap with the piston compression cycle is a cool way to reduce the volume of the compression stroke under low load driving(rather than Atkinson I consider it temporary displacement reduction).
Regardless, intake valve deposits are not a concern at all in these. Direct injection performance on demand but admittedly you really have to put your foot into it to et it’s rated power.most of the throttle space is mapped for efficiency.
Originally Posted by KevinP

Quote

@KevinP there is no "fuel wash" of the back side of the intake valves in a D.I. engine from all the research I've done. When the intake valve is open you have nothing but air and PVC vapors flowing IN to the cylinder and ideally nothing flowing the other way. The last thing you want for fuel efficiency is having raw direct injected fuel going back into the intake manifold where it would be wasted and that would also require some sort of reverse flow which would be hard to induce. Everything about efficient combustion for maximum fuel economy, lowest emissions, and greatest power, opposes dumping raw fuel mixture back into the intake manifold. i think it's a myth. If someone has factual evidence to the contrary I'd love to see it?


That is not completely true. The best example would be in an Atkinson cycle engine where combustion contents are partially forced back up the intake and these lead to BETTER fuel efficiency, not worse. What is washed up into the intake is not lost, it is used the next time you open the intake valve.

https://www.caranddriver.com/news/a...bustion-cycle-and-what-are-its-benefits/

https://www.youtube.com/watch?v=WKKILW3Zj_Y

https://www.youtube.com/watch?v=z45fM2N-4C4

And note.... Toyota engine management allows a vehicle to use both Otto & Atkinson operation in a non-hybrid. That would mean they would get fuel/air mixture on the back of the intake valve at least part of the time, presumably allowing for more intake valve cleaning.


Last edited by Bryanccfshr; 02/09/19 03:43 PM.

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Re: Valvoline Modern Engine Preventing D.I. Carbon? [Re: Bullwinkle007] #5006205 02/09/19 08:19 PM
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Originally Posted by Bullwinkle007
One way to clean the backside of the intake valves is to use carb and intake cleaner and spray it down into the intake while someone holds the throttle at 4k RPM, and spray the entire can. Then change the engine oil. That will also clean the intake manifold. I also clean the MAF sensor every oil change with MAF sensor cleaner


Water injection cleans intake valves and pistons/combustion chambers pretty well.

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