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2G Dual oil catch can setup for maximum effect but.... Advice needed

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EC17PSE

Freelancer
5,867
3,448
Nov 1, 2008
London, UK, Europe
So for a while now I have had issues since swapping to the FF VC and not sure if its because of the lack of baffles inside or the cover on the cap is not great or if its another reason completely so im trying to narrow it down and make it work better for me. While i know collecting it is good its too much too soon so.. here it goes,

I seem to draw alot of oil out the engine (head/VC) in such a short amount of time. And now the cars down for work im wanting to try resolve it as best as I can.

I know the stock system allows air in and from what i read lets air vent from the crank upto the VC but now i have a different cover i dont know if im not letting this air out easy and its pushing or allowing oil to be sucked out of the VC. It could be oils not being allowed to drain back down the block ok.

So i had an idea to make a secondary baffled catch can to run inline with my VS3 unit. But with an added twist and an idea on my can which i dont know if its good or even correct to do.

So from this picture pic at bottom of page (sorry for the jot and lack of precision) i have 2 lines from the VC like normal to the VS3 then im going to add an 8AN on the side in the baffled section to pull from the block (balance shaft inspection hole) this i was hoping would releif the crank pressure and perhaps oil can drain down more freely in the head/block meaning i might not have excess pressure in the head forcing its way out the VC, this is 1 theory i have.

The secondary can would be fed by 1 from the VS3 as it only has 1 exit port and my one can use 1 or 2 ports depending on my findings later on. Now here is what i dont know what to do. I was thinking of adding a pcv valve on the last can right by the intake port back into the intake manifold (actually as i write this im seeing this as a bad idea) as the whole point would be to pump fresh air into the VC and this wont be.
I been reading and looking at this guide for ages trying to figure something out https://www.dsmtuners.com/threads/the-4g63t-pcv-system.366890/

I have never popped a dipstick from excess pressure in the crankcase so i ruled that as a possable but its still in my mind about the piathways and what the stock pcv system does.

I had thought for a while about msking an air / oil seperator and either it being inline with the catch can or it draining back into the pan but since i have no real way of pumping coolant in through it to stop moisture build up i gave up on that idea currently (i might be able to make something work if i had to but not easily)

So has anyone who is more in this sector got some ideas or am i in the right direction to help it overall vs how i was which was VC > VS3 > Intake pipe.

Thanks for reading and hope i can get some ideas from you i can ponder over as i have just about maximised my ideas and i might be missing something or not found it here yet amonst the many many threads i have looked at for guidance or ideas.

Thanks all

Bobby

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I know my engine is old and it might be part of an issue. Unsure though if my logic is right on that or not.

I keep wondering how its being pulled out so much and acting like a hoover and i cant believe 1x10AN can make alot of pressure and pull that much oil from 2 lines off the VC. Thats what makes me wonder if the issue is below the belt and part of the crank case causing oil not not drain good enough and its in the head area and being pulled out.
 
Hey Bobby, my gut is telling me on this one that somethings going else is going on, other than poor ventilation.

Before going down the fabrication rabbit hole, is there a way you can test the PCV system?
 
spare boost gauge you can plumb into one of the existing lines between can and vc? doesnt even have to be that good (napa, whatever)

even a spare map sensor and an analog voltmeter would do the trick.. digital rms may not update fast enough and youre just looking for rough values
 
Hey Bobby, my gut is telling me on this one that somethings going else is going on, other than poor ventilation.

Before going down the fabrication rabbit hole, is there a way you can test the PCV system?
Negative since i have a different valve cover i ditched pcv years ago. I never used to collect as much oil on the old turbo and pcv setup so going to another route has made it happen, if its an underlaying issue then this might have opened it up but i dont know.
 
spare boost gauge you can plumb into one of the existing lines between can and vc? doesnt even have to be that good (napa, whatever)

even a spare map sensor and an analog voltmeter would do the trick.. digital rms may not update fast enough and youre just looking for rough values
I can try this but when the engine is working as its currently in the middle of parts swapping
 
That set up seems unnecessarily complicated in my opinion. You should not be have any issues just running 2 lines from the valve cover the the VS3 and then one back to the intake. There is another issue at hand here.

I do not have baffles in my valve cover currently. I removed them when I added the AN fittings. I did however weld 2 small plates on the underside of the valve cover to act as splash guards / baffles so that oil wasn't able to be completely sucked out / splashed out of the lines. I don't seem to have any issues with my catch can filling too fast and I get a decent amount of blow by now a days because I think my motor is starting to get a tad tired. The first 30k miles of 30psi on and HX40 I never even ran a catch can and had no issues. 35psi and 10k miles later it would blow blue smoke under vacuum after boost. But I have mine set up as I stated above just with no lines from the block. I have however heard of guys complaining about their cans filling up with no baffling or plates welded in at all. Which is why Greengoblin was making the laser cut baffle you could weld back in. I would loved to have gotten one of those but there were no group buys at the time and hasn't been in a while. Even when these were a thing they ran a baffle and splash shield under them https://www.dsmtuners.com/threads/billet-7075-vented-oil-caps.443803/

I'm not sure if your current set up utilizes the inspection port for the balance shaft for ventilation or not, but you may be having issues there if there are not running any type of baffle. I have heard of people using the STM fitting and having issues with catch cans filling up due to the lack of baffling. I am not sure if its due to oil return to the pan, sloshing from the crank, or what. But it has caused issues from my understanding. I have also heard of people welding a small plate on the inside of the block as I did with my valve cover to combat that issue with good results. You may even be able to run some sort of an external "baffle box" by welding a fitting on to a baffled box design that will thread into the BS inspection port and then weld an AN line to the top of the box that will go to the catch can.

The better option there is to drill and tap into the factory ventilation passageway from the block to the head as you would then be drawing pressure from both simultaneously as seen in this thread: https://www.dsmtuners.com/threads/4g63-block-vent.472409/. Its higher up and wont have the issues that the BS port potentially has.

I would definitely weld some small baffles to the underside of your valve cover and get rid of the BS inspection port line if you are currently running it currently.

Now, as far as draining the oil back into the pan. Also not a good idea in my opinion. More so because of the fact that the oil that is coming into the can is contaminated with gasoline / E85 / alcohol which has no place in your oil. Its especially harmful if you are running E85 to have that oil back in your system because of the alcohol. Some oils claim to be better to use with alcohol fuels than others but it should still never be returned to the oil system once its removed. Another reason why you should change your oil more often when running E85. All oil contains gasoline from normal use, but the oil coming from the crank case pressure to the can is going to be more contaminated if that makes sense. Buschur actually made a dip stick for Evos that would allow the catch can to drain back into the pan and came with a check valve, but I always thought it was a bad design and I am not even sure if they still make it.

Sorry if I am preaching things that you already know, but I just figured I would throw it all out there. If all else fails then start looking into doing compression / leakdown tests to check the condition of the motor if you haven't already.

TLDR: Put small baffles in the valve cover under the fittings, Disconnect that BS inspection line if it exists, recheck results. Do not drain catch can oils back to the pan.
 
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I am using stock valve cover with home made baffles, 2 -10an fittings to sealed baffled can pulled in vacuum from 1 -10an to intake. My motor is built lose and sees 30psi+ and over 60lb/min logged. I drain it rarely and is normally just some condensation/ oily mix in there from running e85. I think you have other issues causes it to push that much oil to the can. You could also put a gauge on the lines to catch can and see how much pressure there is aswell. I did this with mine after finishing the breather set up and under boost my crankcase is actually under vacuum or around 0 at all times.I also ditched my pcv as it would push oil into intake manifold on deceleration and cause car to smoke badly.
 
That set up seems unnecessarily complicated in my opinion. You should not be have any issues just running 2 lines from the valve cover the the VS3 and then one back to the intake. There is another issue at hand here.

I do not have baffles in my valve cover currently. I removed them when I added the AN fittings. I did however weld 2 small plates on the underside of the valve cover to act as splash guards / baffles so that oil wasn't able to be completely sucked out / splashed out of the lines. I don't seem to have any issues with my catch can filling too fast and I get a decent amount of blow by now a days because I think my motor is starting to get a tad tired. The first 30k miles of 30psi on and HX40 I never even ran a catch can and had no issues. 35psi and 10k miles later it would blow blue smoke under vacuum after boost. But I have mine set up as I stated above just with no lines from the block. I have however heard of guys complaining about their cans filling up with no baffling or plates welded in at all. Which is why Greengoblin was making the laser cut baffle you could weld back in. I would loved to have gotten one of those but there were no group buys at the time and hasn't been in a while. Even when these were a thing they ran a baffle and splash shield under them https://www.dsmtuners.com/threads/billet-7075-vented-oil-caps.443803/

I'm not sure if your current set up utilizes the inspection port for the balance shaft for ventilation or not, but you may be having issues there if there are not running any type of baffle. I have heard of people using the STM fitting and having issues with catch cans filling up due to the lack of baffling. I am not sure if its due to oil return to the pan, sloshing from the crank, or what. But it has caused issues from my understanding. I have also heard of people welding a small plate on the inside of the block as I did with my valve cover to combat that issue with good results. You may even be able to run some sort of an external "baffle box" by welding a fitting on to a baffled box design that will thread into the BS inspection port and then weld an AN line to the top of the box that will go to the catch can.

The better option there is to drill and tap into the factory ventilation passageway from the block to the head as you would then be drawing pressure from both simultaneously as seen in this thread: https://www.dsmtuners.com/threads/4g63-block-vent.472409/. Its higher up and wont have the issues that the BS port potentially has.

I would definitely weld some small baffles to the underside of your valve cover and get rid of the BS inspection port line if you are currently running it currently.

Now, as far as draining the oil back into the pan. Also not a good idea in my opinion. More so because of the fact that the oil that is coming into the can is contaminated with gasoline / E85 / alcohol which has no place in your oil. Its especially harmful if you are running E85 to have that oil back in your system because of the alcohol. Some oils claim to be better to use with alcohol fuels than others but it should still never be returned to the oil system once its removed. Another reason why you should change your oil more often when running E85. All oil contains gasoline from normal use, but the oil coming from the crank case pressure to the can is going to be more contaminated if that makes sense. Buschur actually made a dip stick for Evos that would allow the catch can to drain back into the pan and came with a check valve, but I always thought it was a bad design and I am not even sure if they still make it.

Sorry if I am preaching things that you already know, but I just figured I would throw it all out there. If all else fails then start looking into doing compression / leakdown tests to check the condition of the motor if you haven't already.

TLDR: Put small baffles in the valve cover under the fittings, Disconnect that BS inspection line if it exists, recheck results. Do not drain catch can oils back to the pan.
I did reply yesterday but lost it all when the site went funny so i got to try remember what i said now.

The drain back to the pan was only if i could get water / heat into the air / oil seperator as thats hoe they have to be run, these units sre cimpletely different setup then a catch can and after this it would then be taken to the catch can fornthe excess fumes snd deposits left over as only the oil will drain back once collected. It takes some designing to make s good design for this chamber.

It is abit more involved then i wanted but if it has to be then it has to be. Welding is a no go because its an anodized cover and the frontline unit has small covers over the last cam cap but it might not be doing great but i dont know if its that or because it sees this exit as the less restrictive so gets forced through or sucked up through this as no other air source is present coming into the cover.

The inspection port is my only option currently as no welding or drilling in the block will be done since its a working block and in the car. This type of work wikl be done later on when i do a rebuild and figure this all out, by then i might even end up using a vac pump to pull the air out but for now im going to try the block location and see if its going to help.

I have tried to figure out what could of made it do this before swapping to a catch can but i cant think of anything but the fact the VC is not baffled and no air (clean) can enter in.

Yesterday i did re examine the vs3 can and figured i might have noticed something thats not helping on the inside. When yiu remove the exit port and filter you see the 2 inlets are straight into a small mesh area to collect oil and thats plated and surrounded but next to it is 2 large holes so in my thinking the oil is getting into that media and then being pulled sideways through the hole rather then dropping and air forced around the tank. So in doing this its excess is dripping off but the bulk is being pulled through before its dropped. I think the bottom needed more holes and the side needed no holes to force the oil down and then cannot jump side ways. No i did not close up these holes as i cant get a tig torch in there but its something im going to look into and make it go the long way around.

I think thats about what i wrote, i cannot remember
 
I am using stock valve cover with home made baffles, 2 -10an fittings to sealed baffled can pulled in vacuum from 1 -10an to intake. My motor is built lose and sees 30psi+ and over 60lb/min logged. I drain it rarely and is normally just some condensation/ oily mix in there from running e85. I think you have other issues causes it to push that much oil to the can. You could also put a gauge on the lines to catch can and see how much pressure there is aswell. I did this with mine after finishing the breather set up and under boost my crankcase is actually under vacuum or around 0 at all times.I also ditched my pcv as it would push oil into intake manifold on deceleration and cause car to smoke badly.
What i might have to do is run an adaptor on the block and head and video the pressure when driving and see what its doing. The engine is old and tired sure so blow by is expected but i never had major issues that i found (or i just missed it).
 
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