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Discussion Starter #1
Or why you don't need a catch can (or two).


During engine idle there is a huge vacuum in the intake manifold, less and less vacuum as the throttle plate opens more and more("A"), until at WOT the BOOST comes into play and the intake manifold begins going positive with respect to atmospheric pressure("B").

A.) The reverse flow prevention check valve remains open as long as the pressure on the crankcase side is higher than the intake manifold. So the airflow path is from the air hose connection just downstream of the engine air filter (filtered air), through the engine crankcase and then out the check valve and into the intake manifold, subsequently entering the combustion chamber and being burned.

B.) If/when/once the onset of boost results in the intake manifold pressure going positive with respect to the crankcase pressure the check valve closes blocking any flow into the intake manifold from the crankcase. Now, any blowby that would otherwise pressurize the crankcase simply flows out what was the inlet path/hose, through the turbo impeller, CAC, and enters the intake manifold etc, etc.

The engineering design theory being that if the crankcase gasses (etc.) are continuously evacuated in the manner there will never be enough gas/oil/water/etc. entering the combustion chamber all at one time to adversely affect the engine operation.
 

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What happens when hot air hits cold aluminum metal? Condensation? Making water add in a little oil and now you have what I see in the pictures you guys post.
 

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I wonder if the fella with 150k miles on his EB has a catch can. I doubt it.
 
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Discussion Starter #5
Damn, I must have a hole in my piston somewhere, cause my can is certainly collecting a lot of gunk.

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"lot of gunk" Yes, but over how many miles and cold engine starts??

What's it like if you empty the catch can after each engine shutdown?

If that "gunk" were properly "metered" into the intake as you drive as the Ford design engineers planned what might be the adverse results.

Plus what you're looking at in that catch can is an emulsion consisting primarily of water (60-80%), oil (10-40%), and air (60-90%, by displacement).

Ever whip egg whites to make a Tom & Jerry? Most of the resulting volume equals tiny air bubbles.

What's the raw volume of the ingredients of mayonnaise before whipping it up into emulsion form?
 

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Discussion Starter #6
What happens when hot air hits cold aluminum metal? Condensation? Making water add in a little oil and now you have what I see in the pictures you guys post.
Condensation occurs primarily post engine shutdown as the engine cools and the water molecules within atmosphere inside the crankcase condense onto the metal surfaces. Once the engine is restarted and rises to operation temperature any water molecules in the incoming airflow have a greater tendency to atomize into a mist rather condense moreso.

Any water in any form reaching the HOT combustion chamber will be INSTANTLY converted STEAM.

Enough water(***1) converted to steam and you get misfires(***2) resulting from excessive(***3) compression pressure.

***1) Pooled CAC condensate.

***2) Sparkplug/COP flashover leaving carbon tracking there increasing the misfire rate.

***3) Broken connecting rods due to hydro-locking.

NOTE: Full, SOLID, hydro-locking is not required for breaking connecting rods
 

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"lot of gunk" Yes, but over how many miles and cold engine starts??

What's it like if you empty the catch can after each engine shutdown?

If that "gunk" were properly "metered" into the intake as you drive as the Ford design engineers planned what might be the adverse results.

Plus what you're looking at in that catch can is an emulsion consisting primarily of water (60-80%), oil (10-40%), and air (60-90%, by displacement).

Ever whip egg whites to make a Tom & Jerry? Most of the resulting volume equals tiny air bubbles.

What's the raw volume of the ingredients of mayonnaise before whipping it up into emulsion form?
This is not an emulsion:



This is after 96 miles of Florida driving, with about half a dozen cold starts. I don't want that oil, water, and gasoline cocktail coating my intake, etc.
Your presumption that Ford builds engines with durability in mind is flawed. All Ford design for is manufacturing and system-design simplicity, maintenance consideration of the average user, and ability of the system to operate as intended for the duration of warranty.
I keep my vehicles longer than that and Ford won't be there to clean my intake valves 60k miles from now.

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^^ Looks like the same kind of sludge milkshake we used to dump out of the "slobber boxes" on the M113 APC's and M2 Bradley Fighting vehicles I used to wrench on. I suppose those could also be referred to as catch cans. Even though they were diesel powerplants I would imagine the basic mechanisms of condensation and crankcase pressure are similar.
 

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Discussion Starter #11
I stand corrected. That being said, I still don't want this mix coating the inside of my intake, or top of my valves. I don't understand what you're trying to accomplish with your posts?

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Then might I suggest that you also devert the EGR "gunk" as it will do just as much or more to coat the inside of the intake manifold and the backside of the intake valve. In point of fact your trapped emulsion might well have helped to "wash" the EGR deposits away otherwise.
 

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Then might I suggest that you also devert the EGR "gunk" as it will do just as much or more to coat the inside of the intake manifold and the backside of the intake valve. In point of fact your trapped emulsion might well have helped to "wash" the EGR deposits away otherwise.
Hey, you come with a reasonably priced system to do that, I'll look to install it too. For now, I'll stick to something that works for me.

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Discussion Starter #13
Hey, you come with a reasonably priced system to do that, I'll look to install it too. For now, I'll stick to something that works for me.

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Easy, just close off the EGR exhaust gas return tube.

But expect lower FE and ignore the CEL.
 

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There is no system in the world that any crankcase accumulation should ever back flow out through the fresh, or cleanside of a PCV system....this is amazing to think this is all normal.

I can't debate with another that doesn't understand the basics of proper crankcase evacuation or my head will explode. I do urge the OP to leave his as is by all means, but to try and convince those that do want the best for there investment is a disservice to all here.
 

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Easy, just close off the EGR exhaust gas return tube.

But expect lower FE and ignore the CEL.
Show me where it's at, please.
Do you even know what motor we are discussing?
 

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Discussion Starter #18 (Edited)
There is no system in the world that any crankcase accumulation should ever back flow out through the fresh, or cleanside of a PCV system....this is amazing to think this is all normal.

Then would you be ever so kind as to explain to the rest of us just why crankcase pressure resulting from blow-by during BOOSTED WOT operation would not escape the crankcase through an open path to atmospheric pressure?

I can't debate with another that doesn't understand the basics of proper crankcase evacuation or my head will explode. I do urge the OP to leave his as is by all means, but to try and convince those that do want the best for there investment is a disservice to all here.
Did I just hear someone's head explode?
 

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Engines with dual vvt do not use Egr valves usually. They use camshaft overlap for egr.
Correct. The variable cams are constantly performing functions and the technology is very impressive.

I had to chuckle on the thought that crankcase pressure build up is some how planned and a form of evacuation? LOL.
 

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Discussion Starter #20
Correct. The variable cams are constantly performing functions and the technology is very impressive.

I had to chuckle on the thought that crankcase pressure build up is some how planned and a form of evacuation? LOL.
But I don't see you answering the question...?

So, again....

What prevents the blow-by gasses from flowing OUT the INTAKE path under WOT and boost when the PCV check valve is closed ???


And do you truly believe that the Ford design engineers do not foresee the need to prevent crankcase pressure build up at those times?
 
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