Oil's Effects on Direct Inj Intake Valve Deposits?

[Danh]

I
Originally Posted By: badtlc
Originally Posted By: Joe90_guy
To me it sort of explains why oil like this can create deposits on inlet valves. The distilled, light front-end of the base oil has been separated from most of the additives in the DI pack because these tend to be heavier molecules. Specifically the base oil hitting the back of the inlet valves will be essentially free of antioxidant. As a result it will be very oxidatively reactive in an environment which is both very hot and rich in oxygen. Do I have absolute conclusive proof of this? No. Does the theory sound plausible? I'd say definitely yes.


The problem is there is no evidence showing that what is in the catch can is what is forming deposits. Like I have said previously in this thread, people with catch cans still get intake valve deposits. So whatever is forming the deposits isn't getting caught in the catch cans. I don't think you can take anything from the catch can analysis.


You are probably right. But if whatever is in catch cans isn't the problem, why do manufacturers bother with oil/vapor separators in PCV systems? They're there for a reason; if not to prevent intake valve deposits...

 

[afree]

How can you prove the valves still collect deposits after a catch can is installed? Only way to prove this is to replace or clean the valves when adding a catch can in order to see the whats deposited on rhe valves.

 

[wemay]

Originally Posted By: afree
How can you prove the valves still collect deposits after a catch can is installed? Only way to prove this is to replace or clean the valves when adding a catch can in order to see the whats deposited on rhe valves.


Many Catch Cans have been installed on new vehicles with very very low miles and still fell victim to IVD.

 

[afree]

Originally Posted By: wemay
Originally Posted By: afree
How can you prove the valves still collect deposits after a catch can is installed? Only way to prove this is to replace or clean the valves when adding a catch can in order to see the whats deposited on rhe valves.


Many Catch Cans have been installed on new vehicles with very very low miles and still fell victim to IVD.

What sort of catch can design? This plays a huge roll in what gets captured by the can. Not all catch cans are created equal.

 

[Joe90_guy]

I would also say location of the catch can, and the location's influence on the catch can's operating temperature is important. A catch can can only catch what it can condense and will be more effective the colder it gets.

I suspect if engine designers made even some cursory effect to cool what went through their PCV systems, they would stop a lot of oil from creating downstream problems.

 

[KrisZ]

Originally Posted By: Danh
You are probably right. But if whatever is in catch cans isn't the problem, why do manufacturers bother with oil/vapor separators in PCV systems? They're there for a reason; if not to prevent intake valve deposits...


Intake valve deposits were not a problem before wide implementation of DI and vehicles still had PCV systems and oil separators. I think the main reason for them is to minimize the oil loss as well as limit the amount of combustion by-product (it's not all oil) vapors going through the cylinders to prevent altering the A/F ratios, predetonation, spark plug fouling and possible negative effects on catalytic converters.

 

[Joe90_guy]

If you go back to the late '80s, Inlet Valve Deposits were fast becoming a problem on ordinary engines. We saw this particularly in Europe as oil refineries installed masses of cracking capacity in response to the second oil crisis.

This prompted the oil companies to start adding detergents to gasoline and this largely cured the problem. It's probably truer to say that IVD issues only returned when GDI engines were introduced. The reason being that detergent chemicals were no longer hitting the back of the inlet valves, so were utterly ineffective.

Three things have happened since the '80s...
First gasoline quality has generally got much better. Much of the real [censored] that used to be dumped in gasoline has now gone, sulphur levels have decreased and a lot of gas is now loaded up to the gunnels with antioxidant.
The second thing is that as we have moved to thinner, fuel economy driven engine oils, oils have become more volatile. This is very apparent if you look at current US Group II 5W30s (Dino oil).
The third thing is obviously the emergence of GDI engines. IVDs are more of an oil related issue on GDI but I suspect, because some (not all) of these engines are prone to fuel dilution, that it's evaporating fuel that is 'powering' the transfer of the most volatile part of the oil to the engine intake.

 

[badtlc]

Originally Posted By: afree
How can you prove the valves still collect deposits after a catch can is installed? Only way to prove this is to replace or clean the valves when adding a catch can in order to see the whats deposited on rhe valves.


There were a few mini/bmw owners that did just that. They had problems, cleaned the valves, installed catch cans and documented the reforming of deposits again. They were using high end catch cans, not home brew solutions.

 

[badtlc]

Originally Posted By: Danh

You are probably right. But if whatever is in catch cans isn't the problem, why do manufacturers bother with oil/vapor separators in PCV systems? They're there for a reason; if not to prevent intake valve deposits...


all sorts of reasons. the PCV system is actively controlled and the contaminants from the oil weren't supposed to be combusted in the first place. PCV vapors can reduce octane rating of the A:F and cause dirty intakes/throttle bodies.

 

[circuitsmith]

Originally Posted By: Joe90_guy
I suspect if engine designers made even some cursory effect to cool what went through their PCV systems, they would stop a lot of oil from creating downstream problems.


Then it would collect and clog in the PCV plumbing.
PCV hoses often have a layer of insulation to prevent condensation.

 

[Jetronic]

pcv systems now come with heaters to prevent clogging when freezing

 

[afree]

Originally Posted By: badtlc
Originally Posted By: afree
How can you prove the valves still collect deposits after a catch can is installed? Only way to prove this is to replace or clean the valves when adding a catch can in order to see the whats deposited on rhe valves.


There were a few mini/bmw owners that did just that. They had problems, cleaned the valves, installed catch cans and documented the reforming of deposits again. They were using high end catch cans, not home brew solutions.


Do you have a link to this?

 

[Uber_Archetype]

Originally Posted By: badtlc
The problem is there is no evidence showing that what is in the catch can is what is forming deposits. Like I have said previously in this thread, people with catch cans still get intake valve deposits. So whatever is forming the deposits isn't getting caught in the catch cans. I don't think you can take anything from the catch can analysis.

What I take from my catch can analysis is pretty obvious: There is a significant amount of condensed crankcase blowby no longer entering the intake tract. This is at the very least, slowing the formation of intake deposits. Catch cans are certainly not all created equal. Different engines produce different amount and type of of intake-recycled discharge. EGR is also a contributor.

Smart shade-tree mechanics take all this into account and create systems to minimize and remove intake buildup. Well-executed catch cans are just one tool in the toolbox.

 

[Garak]

Originally Posted By: Joe90_guy
First gasoline quality has generally got much better. Much of the real [censored] that used to be dumped in gasoline has now gone, sulphur levels have decreased and a lot of gas is now loaded up to the gunnels with antioxidant.

You know you can't say that. It's sacrilege in North America to say anything except that gasoline technology peaked sometime before 1970.

 

[Shannow]

Originally Posted By: Danh
You are probably right. But if whatever is in catch cans isn't the problem, why do manufacturers bother with oil/vapor separators in PCV systems? They're there for a reason; if not to prevent intake valve deposits...


http://mewagner.com/?page_id=1221

Is a good read.

A poor baffle design, replaced with a sound baffle design reduced oil consumption through the PCV by 98%

 

[SteveSRT8]

Everyone focuses on the small percentage of vehicles experiencing problems while millions motor along just fine in complete ignorant bliss.

The millions upon millions of cars WITHOUT catch cans are the most revealing statistic of all. Virtually any engine with oil in it generates vapors in the crankcase. Most have some sort of PCV.

Yet they run fine for hundreds of thousands of miles. Even with (gasp) oil in the intake. It's fine to put a can on, I run one on a supercharged application, but imagining that it will cure this deposit issue is laughable when there are quite a few DI vehicles with ZERO issues...

 

[wemay]

Originally Posted By: SteveSRT8
Everyone focuses on the small percentage of vehicles experiencing problems while millions motor along just fine in complete ignorant bliss.

The millions upon millions of cars WITHOUT catch cans are the most revealing statistic of all. Virtually any engine with oil in it generates vapors in the crankcase. Most have some sort of PCV.

Yet they run fine for hundreds of thousands of miles. Even with (gasp) oil in the intake. It's fine to put a can on, I run one on a supercharged application, but imagining that it will cure this deposit issue is laughable when there are quite a few DI vehicles with ZERO issues...


Absolutely 100% agree! How many parents sit in their GDi SUV's idling in front of their child's school, waiting to pick them up, after which making a quick run to the grocery store, are contemplating this "issue" in their extremely busy day?

 

[Uber_Archetype]

Originally Posted By: SteveSRT8
The millions upon millions of cars WITHOUT catch cans are the most revealing statistic of all.

The only thing that statement reveals is a generalization fallacy basically saying all cars are the same in terms of intake deposits.

Oh, and also the fact that this so-called "statistic" you refer to was pulled from your nether-region - unless you'd care to throw out a cite.

 

[artificialist]

Originally Posted By: lubricatosaurus
Originally Posted By: ccap41
You are correct. Which is why I was hesitant to use anything in the first place. But, the CRC specifically says it is safe for turbo engines. I know that doesn't magiaclly make it okay but it made me feel better and, let's be honest, if the turbo went out from that it would have gone out in the next few thousand miles, right? It would have still been covered under warranty and I have no clue how it could have been proved that I used something like this anway.


Maybe a good solution: Dampen 3/4 of your paper-element air filter in CRC or Gumout MultiSystem or B-12 Chemtool or Gumout All-In-One (most of those have PEA in it or wicked solvents at least). Then drive normally, letting air flow gradually vaporize the chemicals to mix with air and wash over the intake valves as you drive.

I wouldn't do that.

Those chemicals are not approved for cleaning mass air sensors, and the mass air sensor is always immediately downstream of the engine air filter.

There may be a GDI engine that uses speed density, but I have never seen one. If there exists a speed density GDI engine, your method might be safe to use.

 

[wemay]

Originally Posted By: Uber_Archetype
Originally Posted By: SteveSRT8
The millions upon millions of cars WITHOUT catch cans are the most revealing statistic of all.

The only thing that statement reveals is a generalization fallacy basically saying all cars are the same in terms of intake deposits.

Oh, and also the fact that this so-called "statistic" you refer to was pulled from your nether-region - unless you'd care to throw out a cite.


http://www.autoguide.com/auto-news/2015/...n-engines-.html


Michael Karesh, the developer of TrueDelta.com said carbon buildup is “not an issue for all direct-injected engines” based on the data he collects. His website surveys the owners of around 33,000 different vehicles to acquire relevant and timely data about vehicle reliability and fuel economy among other things.

But of course there are some instances of deposit-related issues that have popped up. Karesh said, “The only engines it’s reported quite a bit is [with] the VW/Audi 2.0T and then the Audi V6s.” He also said, “I know there are some BMWs that end up with carbon buildup as well.”


...For the time being Karesh said that according to his data, “Clearly it’s a VW/Audi problem and not much else.” Elaborating he also said, “We’ve got other direct-injected engines and it’s not showing up for those.”

Since carbon-related issues with direct injection seem to be sporadic at best Karesh said this is good news for drivers. “It means you don’t have to plan on decarboninzing your engine every two years for $800 a pop.”