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Discussion Starter · #1 ·
Anyone know where I would “cut in” an oil catch can? On the Focus it looks buried under everything. Will it be hard on this car? Because this is direct injection as well as turbocharged I am sure the intake valves are going to have major issues as we start to put miles on these cars.
 

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Discussion Starter · #3 · (Edited)
I am a bit confused, what is hose #2? Its clear that #1 is going from PCV to the intake manifold. From the picture it looks like its going from the air intake to the block (or head)? Please school me.
IF we are just talking about just cutting into line # 1 for the catch can this looks like it would be very easy (as long as there is a place to hang the can). We have it a lot easier than the Focus ST guys. Am i seeing this right?
 

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When the PCV valve is open ( vacuum in the intake manifold, no turbo boost), crankcase gases are draw into the intake manifold and burnt during combustion. This causes a vacuum in the crankcase because it is a closed loop system. You don't want negative pressure in the crankcase so a second hose is used, hose two. Fresh filtered air is drawn into the valve cover through hose two so there is no negative pressure in the crankcase.
Now when the PCV valve closes due to positive manifold pressure (turbo boost), the flow reverses. Crankcase gases flow out through hose two into the inlet pipe,through the turbo and intercooler and into the intake manifold to be burnt during combustion. So in theory you could use two catch cans, one in hose one and the other in hose two.
The majority of oil mist is drawn into the inlet manifold from the PCV valve. If you use your car at a track day where you spend a lot more time on boost then more oil mist will be going through hose two.
 

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Not sure this engine uses a PCV valve per se rather like many of the last US motors ( I have owned and worked/tinkered with either engine swaps or adding oil catch cans and all have been V8's so i may be off here)
Those motors have used a Orfice in the PCV system rather than a valve and looking at the valve cover from the manual (I have not taken mine apart to look) It would seem to suggest a Orfice of some sort

Not the best pictures and drawing but i hope it helps
Valve Cover top.jpg
Valve Cover bottom.JPG



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It definitely uses a one way PCV valve and a PCV valve is not just a check valve but a flow control as well.( orifice ). Remember its turbocharged . Now picture pumping 21psi into the crankcase.
 

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So that would be like a reed valve on two stroke engines (like a one way flapper type) All new to me so i am just tryin to learn :)
Sorry, I might have come across as a bit arrogant . Usually its like a disc in a circular housing, the disc moves backward and forward depending on intake manifold pressure and only allow flow in one direction. When its open it controls the amount of flow, you don't need all that manifold vacuum to draw in the crankcase fumes.

A common PCV valve in the open position and closed position
 

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Discussion Starter · #12 ·
How about a "how to" for those not that technically inclined. Also is the check valve needed? Another poster seems to think the system needs to flow in the other direction as well.
 

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Hi Vixenlotus

I used a check valve because the Separator used is not designed to be pressurised. Without the check valve installed the separator would be subject to full boost pressure. IMHO, I would isolate the catch can/separator from boost in any case. Looking at the images you can see that it is connected in series between the intake manifold and the PCV valve outlet on engine valve cover. What exactly do you need to know?.
As far as installing a catch can in hose two, you could do it. The problem or more to the point, one problem is the fact that the flow changes direction as pressure in the intake manifold changes from vacuum to boost. Catch cans/separators are usually designed to work in one direction. Any oil trapped in the can may get sucked back out as the flow direction in hose two changes.( In theory )
There is also a baffle inside the valve cover where hose two is connected and it seems to be doing a reasonable job of keeping oil out of the intake tube. See Image

Turbo Inlet, oil free.
 

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I should add, this is not the type of job to do unless your confident and willing to take the risks involved when modifying a vehicle from the way a manufacture designed it.
I am not a Engineer, I have clamped rubber hoses onto plastic fittings that are NOT designed to be clamped in this way. Because of this I have added support "P' type clamps to make sure any engine movement does not pull the hoses off or break the plastic fittings. Worst case, oil spaying over a hot turbo-fire-no insurance.
I would recommend that people wait until a supplier designs a catch can system for the Fiesta ST and releases it to the market.
Catch can are not "set and forget", they need to drained at regular intervals, inspected for leaks and hose clamps checked for tension.
 

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Hi,

See the image below. The catch can needs to be installed between the PCV valve and the inlet to the intake manifold.
reviving thread from the dead lol
anyways, i was thinking, doesn't hose 2 when you are accelerating, sucks air/oil to the inlet turbo compressor? please school me thanks
 

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reviving thread from the dead lol
anyways, i was thinking, doesn't hose 2 when you are accelerating, sucks air/oil to the inlet turbo compressor? please school me thanks
He explained the PCV system very well in post 5. As to the question at hand yes, under boost the PCV valve is closed so crank case blow by will vent through hose 2 and vacuum will suck it into the turbo inlet.
 

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When the PCV valve is open ( vacuum in the intake manifold, no turbo boost), crankcase gases are draw into the intake manifold and burnt during combustion. This causes a vacuum in the crankcase because it is a closed loop system. You don't want negative pressure in the crankcase so a second hose is used, hose two. Fresh filtered air is drawn into the valve cover through hose two so there is no negative pressure in the crankcase.
Now when the PCV valve closes due to positive manifold pressure (turbo boost), the flow reverses. Crankcase gases flow out through hose two into the inlet pipe,through the turbo and intercooler and into the intake manifold to be burnt during combustion. So in theory you could use two catch cans, one in hose one and the other in hose two.
The majority of oil mist is drawn into the inlet manifold from the PCV valve. If you use your car at a track day where you spend a lot more time on boost then more oil mist will be going through hose two.

He explained the PCV system very well in post 5. As to the question at hand yes, under boost the PCV valve is closed so crank case blow by will vent through hose 2 and vacuum will suck it into the turbo inlet.
would it be wise or not wise to put a check valve on hose 2 so no air goes to the intake but air can go to the engine?
 

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No check valve on hose 2. There won't be boost pressure on that can. Make sure you use a baffle/screen in the can or it'll be a waste of time. Curious to see how much you catch if you try this.
 

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No check valve on hose 2. There won't be boost pressure on that can. Make sure you use a baffle/screen in the can or it'll be a waste of time. Curious to see how much you catch if you try this.
i dont think you will catch anything, i have taken the hose of a couple of times and is bone dry
 

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Interesting. Good to know. Yeah if the hose is dry then it's probably not an issue. How many miles have you done?
My can on hose 1 has caught a fair bit so I'm leaving mine on there. For that can you want a boost proof can or check valve.
 
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