DIY Upper Intake Cleaning - DI Engines

[ChrisD46]

Originally Posted By: OneEyeJack
This DI architecture needs more work to get these problems solved. Addition upstream injectors are being added to some engines and this can't be anything other that a direct response to these problems. The push toward this DI stuff is probably a response to smog legislation no matter what the marketing department proposes. It's expensive. If you drive one of the vehicles you probably need to get after the problem from the day you drive off the lot, maybe even confirm the problem with a UOA or two. It appears that you need to get into the intake track upstream from the combustion chamber and include the valves. Chemicals must be used right away to keep up with the problem instead of trying to fix it later. I went through the walnut blast with an Audi even before DI. I don't think I'll be one of those people with a DI engine anytime soon. I can find other ways to help save the earth.
+1

 

[SHOZ]

Most of the buildup that is problematic is on the backs of the valves correct? The sludge that pools in the intake form the PCV can be mitigated with a good catch can setup.

Some time the FIs to spray a minute amount when the valves are open and you get regression or air pulled back in over the valves.

Otherwise the traditional Seafoam treatment is what most amount to.

 

[circuitsmith]

I wonder if a catch can on the PCV line would help.
It would have to be periodically emptied.

 

[SHOZ]

It works on my 2L Turbo. Keeps the intake manifold very clean. It is what I call a condensation can and located outside the engine compartment in ambient temp air. I have a drain hose on it and easily drain it at oil change time. get maybe 100ml at a time over 5k miles. Really depends on the climate as humid conditions will cause a lot more to be collected.

 

[Quattro Pete]

Maybe this is specific engine dependent, but some new hypothesis suggests that catch cans don't really help much, because there are other reasons why these deposits form...

Quote:
A major breakthrough has occurred recently on the build-up issue and the exact cause has been isolated. The port injection design is actually not the cause but merely the reason why the issue cannot be controlled and managed through normal fuel derived cleaning processes.

It is now understood why even the most advanced post combustion cleaning fuel additives or solvent based cleaning through the fuel /air intake tract have little effect. Furthermore, it is also understood why rerouting crankcase breather by-product into segregated catch cans or using water/methanol injection are limited in their ability to reduce carbonaceous build-up in the inlet port and inlet valve surfaces.

[...]

So if the small amount of oil bypassing the valve stem seals is normal, and indeed required, then why the excessive build-up on the valves? One hypothesis is that;

The oil is being broken down by the catalytic (reacting) action of the materials used to manufacture or coat the valve stems. In particular, nickel and chrome alloys. This pyrolytic decomposition is widely recognised in the industrial power generation sector where hydrocarbons are in contact with superalloys used in the construction of combustors, nozzle guide vanes and exhaust components.

In layman’s terms the materials used to manufacture and harden the valves is reacting with the lubricating oil creating an aggressive bond between the lube and the valves!


http://www.oilem.com/turbo-fuel-stratifi...ild-up-problem/

 

[SHOZ]

My last car was a Ford Taurus SHO V8 32 valve motor. 8 of the 16 intake valves were "dry" meaning they did not have any direct fuel spray. The dry ones would coke up badly on the back of the valve head and the stems. The wet valves had hardly any build up. It was pretty obvious the fuel spray kept them clean.

When a good working catch can stopped the PCV sludge from forming, this dry valve also stayed relatively clean. Though not as clean as the wet valve.

In this pic the dry valve intake port is on the right.

Here is the manifold above that valve. The throttle plate is above the dry valve.

 

[ChrisD46]

It appears there is no easy solution for keeping DI engine intake valves clean when no fuel spray can reach the back of the valves where the carbon collects and causes deposits .

 

[SHOZ]

I disagree. Use a catch can located in a cool area which should be viewed as a condensation collector, and make sure it is big enough.

You have to ask where is the hydrocarbon coming from? Most is the PVC sludge, some is reversion of gasses inside the cylinder. The condensation collector will stop most of the sludge from getting into the intake and then onto the valves.

This sludge is lighter hydrocarbons and water. The water evaporates when inside the motor and the hydrocarbons deposit on the valves and get baked off when the engine is shut off turning into carbon.

 

[badtlc]

Keep the valves hot once in a while isn't hard.

 

[ChrisD46]

So your saying the 'ol Italian tune up will take care of DI intake deposits ? ... Something like 20 minutes over 3K RPM ?

 

[Quattro Pete]

Originally Posted By: Quattro Pete
Maybe this is specific engine dependent, but some new hypothesis suggests that catch cans don't really help much, because there are other reasons why these deposits form...

I messed up with this statement. Isolating the oil so that it does not come near the valves certainly helps.

The hypothesis was to explain WHY these stubborn deposits form when the oil does come in contact with the valves.

 

[SteveSRT8]

Originally Posted By: Quattro Pete
Originally Posted By: Quattro Pete
Maybe this is specific engine dependent, but some new hypothesis suggests that catch cans don't really help much, because there are other reasons why these deposits form...

I messed up with this statement. Isolating the oil so that it does not come near the valves certainly helps.

The hypothesis was to explain WHY these stubborn deposits form when the oil does come in contact with the valves.


Indeed. Isolating them from the oil vapors should help, and does. But catch cans, their associated plumbing, and their placement/installation is super dependent on someone knowing what they are and how they work.

You're going to need a very 'cooled' location in order to catch the most crud, most of which should be water...

 

[SHOZ]

Originally Posted By: SteveSRT8
Originally Posted By: Quattro Pete
Originally Posted By: Quattro Pete
Maybe this is specific engine dependent, but some new hypothesis suggests that catch cans don't really help much, because there are other reasons why these deposits form...

I messed up with this statement. Isolating the oil so that it does not come near the valves certainly helps.

The hypothesis was to explain WHY these stubborn deposits form when the oil does come in contact with the valves.


Indeed. Isolating them from the oil vapors should help, and does. But catch cans, their associated plumbing, and their placement/installation is super dependent on someone knowing what they are and how they work.

You're going to need a very 'cooled' location in order to catch the most crud, most of which should be water...



Exactly and why they don't come from the manufacturer's as OEM. I have mine at the frame rail right beside the radiator. A place where plenty of ambient air is flowing.

Before the EcoBoost V6 came out Ford knew of the deposit problem from the V8 Taurus SHO motor. They knew of my success with the 'condensation can'.

The EcoBoost motors have kind of one but it is more a fancy oil separator. It's a chamber located between the heads in the valley that has a stainless steel mesh and a drain that goes into the oil pan. Takes the place of the normal PCV oil separator. Doubt if it works very well because of the heat.

 

[SteveSRT8]

That's always an issue under any hood these days: Heat.

If the can is in too hot of a location its effectiveness is greatly reduced.

Chrysler has a semi-elaborate oil separator in the new hemi's valve cover, but I feel the same way you do... to hot.

The PCV systems used in modern cars are testimony that the OEM's simply do not see this as a problem...

 

[SHOZ]

On my '97 V8 Taurus SHO I had it in the fender well and it was an piece of 3" aluminum pipe. It had a spring loaded check valve that would be closed under vacuum but open when at WOT or when the engine was off. Basically drained itself. Worked great but the EPA would not like it.

The reason OEMs don't use them is what would the consumer do with the sludge and also in the winter it will freeze so if it is not maintained it will cause oil seal problems due to pressure in the crankcase.

i have considered a pin hole in the plug on my turbo side catch can. This way it would drain when under boost.

 

[badtlc]

Originally Posted By: ChrisD46
So your saying the 'ol Italian tune up will take care of DI intake deposits ? ... Something like 20 minutes over 3K RPM ?


I do 20+min at 4,500 RPMs at 80 MPH.

 

[antiqueshell]

The fact is that a working solution already exists and is proven, the extra injector that squirts some fuel on the valves
occasionally to wash them clean.

It does cost extra money, but then just delete some stupid
worthless tech gadgets that don't get used after the first day a customer owns the vehicle.

 

[SteveSRT8]

The extra injector(s) are not there to clean anything.

They are for part throttle use, as many DI engines have cylinder filling issues at certain throttle positions.

Essentially a band aid...

 

[TiredTrucker]

Well, catch cans don't come from the cheap auto and pickup OEM's, but pop the hood on a semi truck and take a look at, say, a Cummins ISX engine. The new emission compliant heavy diesel engines have had CCV since 2007, and they all include a filter on the upper left front side of the engine that basically is a catch can to keep the oil carried along from getting into the intake. In their case, the oil removed goes back to the crankcase. The filter has to be changed regularly though. They had to do this right out of the gate due to the sootier nature of EGR on these engines. Oil and soot is a bad mix in an intake and on valves of those DI diesels. The gasser folks are just now learning of all of this. Well, welcome to the party.

 

[Turk]

Man..... Glad I don't own any DI engines.

No thanks!